Hi all!
Just been snooping around for information/yet more clues to this enigmatic car and came across a topic "3.2 JTS -best exhaust, etc, etc.", the last post to which was some 120 days ago. It was suggested I start a new thread. Not sure it warrants a thread, but here are my two pennies worth anyway!
Although I felt I was done with the work on my engine, it seems I just cannot get enough of information which is relevant to the issues that have surrounded it/dogged it, from new.
Then I stumble over this site which raises some of the issues I have faced.
The Manifold cat on the 3.2 JTS are a real problem insofar as they retain so much heat, the consequences for the engine long term are dire. So, I removed them and fitted Autodelta headers. Removing the manifold cats from an Italian 147 GTA resulted in a substantial drop in engine oil temperature which simply confirmed my belief. And sure enough, mine too dropped, substantially.
I have had several conversations with Autodelta and the estimate I was given for reduced power losses due to improved flow was circa 8 bhp. research and talking to some authorities about this indicates this is a reasonable assumption.
However, the headers were always going to be done in conjunction with replacement camshafts. Again research into valve timing and having fitted after - market camshafts to four of my previous Alfa's, it became clear the JTS static timing creates NVO - Negative Valve Overlap. Exhaust valves close at 9.0 deg. Atdc, Inlet Valves open 11.5 deg. Atdc. Hardly the kind of timing one associates with performance engines. So they were also replaced.
Listening to various YouTube posts of 3.2 JTS exhaust systems, one can hear popping and farting of the exhaust after the driver has lifted, a function of NVO in my opinion and the waste of "scavenging depression" in the manifold due to exhaust valve being closed before the inlet opens.
My engine had a characteristic drone at 2500 rpm and I believed when I replaced the manifolds and the camshafts, it would be resolved. Not so! It just made matters worse. So more research was required, this time into resonators, Helmholtz' cat - backs, rear boxes and Catalytic converters.
Research indicated with "Vee" configurations, to maximise scavenging, the two halves of the exhaust system should be cross coupled. but Alfa chose to couple them after the twin cats, which are restrictive and at a point where the diameter of the exhaust increases dramatically, thus diminishing any negative pressure even further.
I really did not want to spend a shed load of money on a new cat just to prove I was right or wrong - my understanding was still primitive. So the cheapest option, given I thought the Alfa cat was also exacerbating drone in the central section of the exhaust - namely the Alfa resonator/first muffler - was to replace it.
A long search later and I found a Supersprint Central Section - no resonator - at a fair price. The supplier was very helpful with advice and it was soon fitted to my Q4.
2500 rpm drone now gone! True, wide-band exhaust noise is greater, in a pleasant way, but a total absence of "Resonance". Not only that, with the masking effect of the Alfa resonator, having been eliminated, the power in the exhaust gases is now such that the Alfa rear Boxes are overwhelmed and break up with a crackle/rasp/rattle.
However, with less restriction, it became obvious the popping and farting I attribute to NVO was absent. This would correlate with the valve timing going from negative 2.5 deg. to PVO: Positive Valve Overlap, of 23.5 deg. So the rear boxes were rattling apart "On - The - Throttle" and not "On - The - Overrun"!
Cue New Rear Boxes!
They have now arrived and will be fitted on Thursday. But, this simply dragged me back to the Alfa Twin Cat. The restriction they create, and the output of it dissipating any potential for scavenging; because of the post cat - coupling, meant I was faced with a massive modification exercise on the Alfa Cat, the front flexis from the headers and butchering the central Supersprint section to make the Alfa Cat work. Plus labour costs which don't come cheap.
Choice! Autodeltas or Supersprints Sports Cat! I chose Supersprints and as it has to be made to order, I still have five weeks to go before delivery.
It has been a massive undertaking on my part, not to mention expense. All this work was undertaken after the rebuild of my spare engine, in-itself as huge expense.
However, looking back, camshafts, headers and exhaust are inextricably linked and no amount of tinkering with one will resolve the limits of the others. Camshafts cannot function properly with POV, unless manifold restrictions are reduced. Manifold swaps cannot compensate for Alfa's appalling choice of valve timing. And without a genuine free flow exhaust system, including a properly designed cat, which combines the two banks at its input, so much of the benefit of new cams and headers is wasted.
I suppose the question is, was it all worth it. I think it is a great car which could have been up with the best of them. I just saw it as an opportunity to explore a spare Brera engine which suffered a bent crankshaft and wrecked bearings at only 40 - ish thousand miles. When my 159 engine failed at ~ 112,000 miles, it became essential to rebuild the Brera, or scap the 159. Then I would be faced with making another purchase.
The work I have done is still - just - below what I would have had to spend on another car. So at least I have got what a I wanted - a pretty powerful Q4.
Good story!
Vids please!
Google "Holden High Features Engine".
Not sure I agree 100% the 3.2JTS is enigmatic.
Alfa did a pretty reasonable job of coaxing an additional 22kW out of the JTS compared to a "similar" GM/Holden 3.2.
Likely much of this came about via adopting direct injection and upping the compression ratio considerably. Both of these measures will increase torque, however Alfa managed to get their 3.2 to produce more torque at higher revs - more power!
Unfortunately the higher combustion pressure and temperature hurts emissions / NOX etc. Its no wonder the manifold cats get so hot. The relatively small combustion chamber surface (including piston crown) of the JTS will conduct less heat away compared to say the big bore 12 valve 3.0 Busso.
Alfa (and their lawyers!) would be happy to have these manifold cats get stinking hot soon after starting. This feature allows the cats to do their job and clean up the emissions when the rest of the engine is relatively cold. An issue VW had a problem with?
Seem to recall reading somewhere Alfa did some clever stuff with regard to cam phasing at low load / low rpm in order to introduce a bit of EGR and drop combustion temps a bit to manage NOX. Also recall mention of the 3.2JTS able to run very lean at low rpm / low throttle openings. All to do with meeting emissions.
With regard to scavenging, its possibly less important with direct injection as the fuel mixture needs to arrive in the combustion chamber at precisely the correct moment. Easy to do with electronics and a bit of code. Controlling scavenging in a very precise way could be difficult, hence the popularity of turbo charging?
Colin.
Actually, I think it was Holden/GM/Chrysler that did the good job. Personally, Alfa made a bit of a dogs breakfast out of it.
The Brera engine I bought was wrecked at 40,000 - ish miles and as I was retired by then, thought it would be a nice exercise in getting to know what made the JTS 3.2 tick. My 159 at the time was getting on for 110,000, and the chances were I would need to do something about the engine if I was going to keep her long term.
I knew the Brera had a bent crankshaft so it was a definite strip down job. Little information was available to me; the Alfa Dealers largely unhelpful and spares incredibly hard to come by and expensive when I did.
First - off was to have the crank inspected - informed it was too far gone to be pulled back. New crank thousands from Alfa. So I bought a new one from Aus + shells. A$ 900. In the mean time, I found a company which devoted all its time to engine overhauls - and they pulled the crank back. Queue regrind to first over-size , plus balancing. A couple of new con rods and a chain and tension-er kit from Mace, plus an oil pump.
However, horror stories about timing chain stretch and oil pressure led me to investigate these aspects of the engine. Also the perpetual rear bank exhaust position sensor failure codes. Actually, it just spilled over into a two year + project, whereby I designed a Closed Loop Lubrication System: CLLS, which gets oil directly from the Oil Cooler/Filter Unit to the block plug adjacent to the rear bank primary timing chain tension-er. I included a horseshoe loop from the same unit into the main front bank cylinder head Oil Gallery. And shifted the oil pressure switch to the horseshoe, the horseshoe being 12 mm. stainless and the rear line to the timing chain tension-er, 10 mm. No worries about oil pressure or tension now!
Next, came the VVT system whereby I modified the VVT solenoids to close the bridge across the ports to ensure the cam positions were held properly when the ECU set the angle of the cams. At the same time, I modified the rear bank exhaust camshaft position sensor so that the rotor plate of the cam sprocket would cut the field of the Hall effect sensor at exactly right angles. Bosch State the output signal timing is greatly affected if there is any error. To me It looked as if it was about 10 deg. out - they state +/- 0.5 deg. in their spec I believe. These devices are very clever but require accurate alignment. And it seemed perverse that the other three were precisely aligned!
At the same time, research into this engine indicated lubrication was based upon a sump capacity of 4 litres with 1.8 litres in circulation. But the return time of oil back to the sump was particularly long, the oil pick up was high and the drains from the heads were cast into the block in such a position as to cause returning oil to be drawn into windage.
So I bought a later variant pick - up snout, and modified it to lower the screen such that I have about 1 litre extra margin before the pickup becomes exposed, particularly when cornering. I also had the windage plate extended to the full length of the sump and had the drains from the block carried below it by welding aluminium channels/covers to the sump walls, ensuring oil returning from the head, goes nowhere but directly into the sump.
It then was a question of fitting the rebuilt engine into my 159 after its wrecked engine was removed. I am still proud of the guys who did the job given they were not "Alfa Trained". There only experience with Alfa being, they had removed the Brera engine and re installed a good worker. All they asked was to see the 159 running before they started.
They transferred all the ancillaries from the 159, fitting the Autodelta manifolds at the same time, a new clutch and Dual mass flywheel + new release cylinder. The Colombo Bariani Camshafts had been installed, but some of the hydraulic lifters were in the wrong positions. So they had to come off. Happily, I had designed a camshaft removal tool so they were corrected with the engine in situ. Another job they did brilliantly well.
I had the car Dynamometer tested with the old engine, to which I had installed the CLLS as a proving exercise, but before I modified the VVT's. She pulled 266 bhp - 270 din. However, after the VVT mods were done, performance stepped up again to an estimated 280.
However, it is a different story now. With the changes to the valve timing, the Autodelta Manifolds, a Supersprint Centre section - resonator free, new back boxes and the Supersprint Cat coming soon, I hope to be in the region of 315 bhp. At the same time I have being some road - trials, to gauge the improvements. Nothing of course can be confirmed until I get her back on the dyno but, currently having recently fitted a new set of P zeros, after 3000 miles, the rear pair don't have much life left in them. She most definitely has a rear wheel bias as the fronts are still virtually new.
I am hoping to get to a meeting as I need to try a standard 159 or Brera to compare; as the more I drive it, the more it seems it was always like this. Not so. Throttle response is brilliant, bottom - end: she can pull tall gears at low speeds without complaint and she is very quick. I must be careful as BMW and Mercs are like a red rag to a bull. Not the M's or the AMG's, but everything else. Economy is great, upper 20's urban, 30+ on motorways, docile around town, but vicious when winding her up. It continues to surprise me how she carries her weight with ease - that was not the case before.
I will have to get a remap as she ticks over beautifully at 750 rpm, but she sounds menacing, growling instead of purring. But the valve timing has changed a lot which probably accounts for it. Over 3000 rpm she sound delicious, as she piles on the revs - the new rear boxes being substantially straight through above 3k. However below? Got all the grunt in the world, but she will waken the dead in Moscow. That needs sorting. But not till the S.S. cat is fitted. Then I may have to look at doing some exhaust gating to throttle her down below 3k and opening the pipes up above.
Sorry, but there was a couple of other issues I addressed, but omitted from my last post.
This engine, fitted to the 159 and Brera is transversely mounted. Yet the sump is completely devoid of any baffle plates!
As part of the exercise to help prevent starvation - exposing the pick - up, I had baffle plates welded to channel oil via the oil pick - up snout; whatever the direction of travel, cornering, braking or accelerating, the oil will always pass under the pick - up.
Allegedly, complete engines were delivered to Alfa Romeo, which were then stripped down and modified to produce a performance engine worthy of the Alfa Badge. Fundamentally, very little was done. Cylinder heads and VVT's. But little else was done. One can forgive Holden for what was essentially a very straight forward unit. But not Alfa Romeo, who wanted £16500 for a replacement new engine or £12000 for a refurbished one - fully fitted.
The Holden block is superb and is as strong as an ox. The way the crankshaft is embedded into its bearings with side bolts and four main bolts per cap is impressive. The engine without VVT would have had sufficient oil pressure for normal purposes. But for Alfa to run all services from a single pump was stretching things two far. And with restrictions within the oil-ways, resulting in poor flow and pressure regulation, it does not surprise me the 3.2 JTS acquired such a poor reputation. A shame really, because it could have been a great car, up with the best. Now, so many are simply going to the breakers yard.
I am glad I found out what makes this engine tick, or not tick as the case may be. And one thing I am certain of, I shall not be parting with mine anytime soon - if ever. When modified, it is a superb engine and a classic and classy car.
Just to make one further observation. The VVT system is superb. I don't actually believe Alfa designed it, preferring to credit another division of the Fiat Group. When it works properly, it is so agile it could only have come from the Ferrari stable. It results in absolutely seamless progression right across the rev range, with oodles of torque, whatever the revs., with beautiful linearity.
Quote from: Colin Edwards on July 16, 2020, 11:02:43 AM
Google "Holden High Features Engine".
Not sure I agree 100% the 3.2JTS is enigmatic.
Alfa did a pretty reasonable job of coaxing an additional 22kW out of the JTS compared to a "similar" GM/Holden 3.2.
Likely much of this came about via adopting direct injection and upping the compression ratio considerably. Both of these measures will increase torque, however Alfa managed to get their 3.2 to produce more torque at higher revs - more power!
Unfortunately the higher combustion pressure and temperature hurts emissions / NOX etc. Its no wonder the manifold cats get so hot. The relatively small combustion chamber surface (including piston crown) of the JTS will conduct less heat away compared to say the big bore 12 valve 3.0 Busso.
Alfa (and their lawyers!) would be happy to have these manifold cats get stinking hot soon after starting. This feature allows the cats to do their job and clean up the emissions when the rest of the engine is relatively cold. An issue VW had a problem with?
Seem to recall reading somewhere Alfa did some clever stuff with regard to cam phasing at low load / low rpm in order to introduce a bit of EGR and drop combustion temps a bit to manage NOX. Also recall mention of the 3.2JTS able to run very lean at low rpm / low throttle openings. All to do with meeting emissions.
With regard to scavenging, its possibly less important with direct injection as the fuel mixture needs to arrive in the combustion chamber at precisely the correct moment. Easy to do with electronics and a bit of code. Controlling scavenging in a very precise way could be difficult, hence the popularity of turbo charging?
Colin.
Hi,
With regard to clever things Alfa have done with cam phasing and thus valve timing, a standard 3.2 JTS engine exhaust valve closes at 9 deg. Atdc and the inlet opens at 11.5 deg Atdc., giving a NVO of 2.5 deg.
Research demonstrated that the waste products and thus pollutants are the last to leave the cylinder and typically are highest around the cylinder/piston/ring interface.
The piston crown of the 3.2 JTS engine is designed to produce swirl, which draws pollutants away from this area; the cylinder wall/piston/ring interface, into the centre of the piston, which has a small depression resembling a secondary combustion chamber.
The Negative Valve Overlap; in conjunction with the piston crown design, is effective because the piston is 11.5 degrees into its induction stroke before the inlet opens. However, the initial "Swirl Pattern" is sustained when cool inlet air enters the cylinder and swirls around the piston walls, cooling them and initiating the creation of a stratified charge.
The stratified charge is concentrated in the area around the small indentation, to which the previously the UN-burnt products have been drawn. The density of the charge, being stratified is thus most dense in the central region and least towards the cylinder walls.
This stratification continues to exist throughout the compression stroke; again due to piston crown design, until ~ top dead centre, at which point the fuel is injected, the injector directing the fuel to the centre of the stratified charge.
Because of the high compression ratio and importantly, the high pressure of the fuel injected, the fuel goes through a chemical reaction with the trapped Hc's/pollutants at the centre, which modifies the charge. This chemical reaction modifies the charge to the extent that almost complete destruction of pollutants occurs during combustion.
Plus, because the central indentation; pseudo secondary cylinder is small, the actual AFR in that region is quite rich - but only relative to the volume of the indentation. In terms of the total swept volume, it is extremely lean.
Central to this indentation is the spark plug, so ignition is very rapid. As the piston descends however, the increasing volume/space quickly assumes a very lean burn characteristic. Naturally there is very little power in the stroke, but there is sufficient for a solid tick-over and for periods when the driver lifts of the throttle - these are the periods when the AFR is extremely lean for the capacity of the engine. However, the result is very low emissions at low load and tick-over.
Valve timing plays a major role in this as when the engine is switched off, or on tick-over, the inlet camshaft is fully retarded and the exhaust camshaft fully advanced. This results in the engine being very easy to start and when running provides for very light load operation.
However, critical to this is VVT agility which, given it is oil pressure derived, it is not!
Just decided to add a foot note:-
Because of the 2.5 deg. NVO and the piston being 11.5 deg. into the induction stroke, a slight depression exists, helping pull pollutants away from the cylinder wall/piston/ring region. However, with the spray lubrication of the pistons and cylinders, wetting of the rings is continuous. Therefore, to a degree, depending upon the condition of the rings, along with pollutants being drawn into the combustion chamber, oil will also be drawn.
Certainly with my 159, engine oil consumption was a real problem. It seems as though there is a connection between this and piston ring wear. A degree of negative pressure must continue beyond the initial 2.5 deg. NVO and thus, if the ring/piston/bore seal is poor, oil consumption will be high. Mine certainly was.
However, with the change of camshafts and 23.5 degree PVO, oil consumption is very low, the inlet valve now opening at 0.5 deg. Before top dead centre and the exhaust closing at 23 deg. After top dead centre.
It is not untypical of engineering today. It is not, in my opinion, that there are less gifted engineers around. Just with modern company set ups, little thought is given to the overall strength and the skills in any team. And a lot of appointments are political.
Busso was marginalised by the change over with the bias going towards Fiat appointees. It was only two years after he left the company that his V6 went into production, the "New" team having failed to come up with anything. Jano too was virtually marginalised. Chiti too.
The Space Shuttle which blew up on launch, only did so because the engineer who was responsible was bludgeoned into agreeing to the launch, despite the leaking seals on the fuel cells. He spent years suffering mental issues as a consequence.
It is my opinion, the 3.2 JTS could have been a better engine than the Busso V6. After modification it certainly is. It is well, the Giulia 2.9 was designed by an independent team, because sure as eggs are eggs, there is nothing of worth left at Alfa after the Busso generation left. They are in my opinion simply assembling cars, the parts of which come from a multitude of sources.
Quote:- "However, critical to this is VVT agility which, given it is oil pressure derived, it is not!"
Having made this statement, I feel I must justify my reasons for making it.
The rebuilding of my Brera engine did not start immediately I wrecked the 159 engine. I purchased it at least some 18 months prior to that little escapade. So by the time the 159 failed, I had done a fair bit of research into it. And it was this engine which provoked the design of my C.L.L.S. It was quite clear there were serious restrictions within the block and the main timing chain tension-er was right at the end of the oil galleries, where it simply got what was left after all other services were catered for.
With the quantity of white metal shards, liberally scattered around the Brera block, oil ways included, it was obvious the galleries would need pulling through. But I was curious about the VVT's. More so, given there appeared to be shards in them too! How could this be? There are micro-mesh screens across all three of the VVT Solenoid Ports. It became clear the VVT Rotors would need disassembling and inspecting. That is not an exercise for the faint heart-ed.
Sure enough, white metal shards littered the voids of the rotors so it was clear, the screens were not keeping contamination out. On inspecting the VVT solenoids, it was seen, "Flats" are cut into the separating "Walls" of each port, "bridging" the oil pressure feed to them, with both the advance port and the retard port. The existence of these shards in the voids, confirmed oil indeed could circumvent the ports proper and enter the voids via these flats.
From this, it became clear, when oil was flowing to advance or retard valve timing, pressure was being lost as the flats allowed oil to pass straight to the solenoid drain and out into the cylinder head. So flow rate was being reduced, increasing the time it took for the valve timing to "Set", by rotating the rotors. Fundamentally, this affects the inlet camshaft advance and the exhaust camshaft retard much more so than the inlet retard and the exhaust advance, but non the less affects the rotors in both directions. (1)
The camshaft rotors have internal spring bias which rotates them back to their "Parked" positions. These are; inlet camshaft fully retarded and exhaust camshaft fully advanced. (2)
Because of the direction of rotation of the engine, inertia forces the inlet camshaft naturally in the retard position and as a consequence, the strength of the inlet rotor spring is weak and movement is substantially dictated by oil pressure.
However, because of the direction of rotation of the engine, inertia on the exhaust camshaft is also in the retard direction. As a consequence of this, the internal spring of the exhaust rotor is extremely strong, to keep it in the advanced position. Good - luck to anyone who attempts to disassemble these rotors and then put them back together!
When the engine is switched off, the inertia of the valve train, plus the internal spring, returns the inlet camshaft rotor to the fully retarded, "parked" position, where the internal "Pin" locks it into position. In the case of the internal spring of the exhaust camshaft rotor, it is sufficiently strong enough to rotate the camshaft to the fully advanced position - against the inertia of the valve train and the "Pin" locks it into position.
At tick - over, the ECU ensures the solenoid valve ports are set such that the inlet advance port is open to "Drain" and the exhaust retard port is open to "Drain". This ensures the "Pin" remains "In". Operationally, the pin is forced out by the oil feed from the solenoid valves and initiates the "Fill" of the rotor voids to start camshaft rotation. (3)
For this very reason, tick - over should always be a rock - steady 750 rpm.
From the above, it appears obvious to the author, the camshafts; due to the continuous feed - oil "Bleed to Drain" via the solenoid "Flats", the speed of the camshaft rotation is already predisposed to be longer than necessary which compounds the issue of failures of the camshaft positional sensors - particularly the rear bank exhaust camshaft. (4)
However at a time when the ECU has "Set" the valve timing and both the inlet solenoid advance and retard ports are closed, inertia, + the internal spring will cause oil to be forced across the flats bridging the ports, causing the inlet camshaft to retard - move away from the angle dictated by the ECU. (5)
Equally, at a time when the ECU has "Set" the valve timing and both the exhaust solenoid advance and retard ports are closed, the internal spring will cause oil to be forced across the flats bridging the ports, causing the exhaust camshaft to advance - move away from the angle dictated by the ECU. (6)
Thus, the valve timing is never properly "Set", insofar as the angle chosen by the ECU is never maintained. (7)
One extremely detrimental consequence of this is, the exhaust camshaft will always be moving away from any retard angle the ECU has predicted in the direction of advance. Perhaps one of the reasons why the front bank manifold Cat displays evidence of extreme temperature - heat corrosion? This is because, when the engine is making power, the exhaust camshafts will be retarded by the ECU. But with the internal spring forcing oil across the bridge, the exhaust camshaft will become advanced, causing the exhaust valves to open early and causing the cat, and the head, to overheat. (8)
Reading many posts on forums, there have been reports of coil packs burning out on a regular basis, high oil consumption and early degradation of oil. Plus the ubiquitous rear bank exhaust camshaft position sensor failure code. It is inconceivable that Alfa set out to combine so many weak elements in the redesign of the Holden V6.
So there must have be a common denominator to all these issues, surely? Oil pressure certainly has a great bearing on timing chain tension and inadequate pressure will result in poor mechanical timing between front and rear VVT rotors. Reduced oil pressure will also increase the delay in the camshafts setting time between banks (Hydraulic Timing). And a leaky VVT System which fails to "Hold" the correct valve timing angle chosen by the ECU will result in power loss, overheating of cylinder heads, manifold catalytic converters and early oil degradation.
It is all very well to think that the oil temperature gauge on the instrument panel of these vehicles is sitting at the ideal. But that is the temperature of oil in the sump. Research has shown that actual "Bearing Face Temperatures", particularly under load condition, can be as much as 45 degrees higher depending upon application.
This neglects the fact that the returning oil from the heads, exits the block, via huge drainage ports, clinging to their walls by skin effect, where rotating journals immediately pull it into windage, coating the hot, cavernous internal block and increasing the transit time for it to return to the sump.
Chrysler demonstrated that the engine oil of a V8 could be sucked into windage and rotated around the crank, with the sump being completely emptied.
This was at a time when they were experimenting with windage plates and subsequently scrapers. However, the windage plate in this engine did not exist in the original version and was only added later. But it does not extend the full length of the sump. With the latest incarnation of this engine - will run until 2026 - it does. Plus they have made extensive modifications to the block including increased sump capacity and baffle plates to prevent surge. And I am led to believe improvements in oil pressure an flow distribution.
Heavy going I know - sorry for that. But I felt the need to justify my comments.
P.S. It was only some 2 - 3 years later when considering speeding the VVT timing up further that I investigated other systems which use separate oil pumps to derive their oil pressure. The intention was to use two high pressure pumps from the BMW V 8/10/12 - Vanos system I believe. I subsequently bought a couple which I intend to fit at a later date, relieving the engine oil pump of this duty and using the Vanos for everything other than the crankshaft and timing chains.
However, when I came across BMW's solenoid valve, there were no "Flats bridging the ports and if my memory serves me correctly, they only have a screen over the oil pressure feed port. Certainly the screens across the Alfa solenoids will introduce a pressure drop. BMW however appear to protect their system by only having a screen over the inlet, given no oil can circumvent it.
Why did Alfa do what they did is a mystery to me!
But how do you feel about a Ferrari engine in and Alfa? I still feel, Fiat provided a bit of certainty at the time they acquired Alfa and no one knew how things would go - a lot has happened in the World since then. But the biggest mistake for me, was pursue front wheel drive for cars above the size of the Sud.
The 159, Brera and Spider build quality is superb. But as Alfa/Fiat had already decided to close so many of their facilities, there was little option as far as engines were concerned. But the Holden Engine is really not that bad as a power plant. As I say, the block is brilliant and immensely strong. As a work horse; stock engine it is fine. It was Alfa themselves that wanted it to be something else. For that there is no excuse. And there are lots of engineers who cry "Budget - cuts" as a means of excusing their shoddy work. Not just in Alfa. No, for me it is down to them and no one else that the 159/Brera failed. There are guys on the Continent running these things at 600 bhp, so clearly it is strong enough to take it.
I just hope there is enough people willing to take them on as they can be very special. It would be a shame for them to go the way of the Alfa 6. However, I feel so strongly about the failings of the 3.2 JTS, I would be happy to put a Holden Badge on it. And keep the Alfa Badge for my 3.0 GTV. But even that has a Fiat Tipo chassis/floor pan.
Quote from: sportiva on August 02, 2020, 08:08:16 AM
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA :)
Let's be clear. Pomigliano d'Arco was never a 'Fiat' plant pre-takeover. It's the spiritual home of Alfa Romeo Avio and the place where the RA 1000 RC.41 engine was built (in the first factory), powering the Macchi C.202 in my avatar!. Might not be Arese, it's not Milan, but it's Alfa heritage.
I don't have any issue having Fiat Powertrain Technologies product (the TBi) under my hood.
Serious admiration for the technical knowledge conveyed in this informative thread. If only you
were actually consulting to FCA...
Quote from: sportiva on August 02, 2020, 08:08:16 AM
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA :)
Brilliant! If only I could tease the "Lions Head"; not Vauxhall - sorry if I offended Holden Fans, out and insert an Alfa one, that would really put the cat amongst the pigeons. It is no more than a lot of Alfa fans feel and would lay the ghost to rest - they could then get back to talking about cars such as the 155, the one that Fiat killed the Lancia for, to steal their engine He! He!
Busso too was an Aeronautical Engineer!. Jano - both technically brilliant and incredibly pragmatic. Turned his engine out for the 158/9 in under 12 months I believe. Busso's V6, every car manufacturer studied it and no current V6 would be as good without understanding what he achieved. Better than the Dino V6 in my opinion. But the old twin cam was no mean feat either. Probably two of the greatest engines in the World - still to this day.
Quote from: kaleuclint on August 02, 2020, 03:18:58 PM
Quote from: sportiva on August 02, 2020, 08:08:16 AM
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA :)
Let's be clear. Pomigliano d'Arco was never a 'Fiat' plant pre-takeover. It's the spiritual home of Alfa Romeo Avio and the place where the RA 1000 RC.41 engine was built (in the first factory), powering the Macchi C.202 in my avatar!. Might not be Arese, it's not Milan, but it's Alfa heritage.
I don't have any issue having Fiat Powertrain Technologies product (the TBi) under my hood.
Serious admiration for the technical knowledge conveyed in this informative thread. If only you were actually consulting to FCA...
Thanks, just relieving the boredom. Retirement isn't all it's cracked up to be.
OK, so now the 159 goes like she just lost 400 kilograms! However, she sounds like a German Panzer. Above 3000 rpm it really sounds great. Below, absolutely awful.
She always suffered from droning at 2500 rpm. So, with Autodelta Headers, the increased flow just exacerbated it. It didn't move, just became more obvious.
Cue - Supersprint Central section; no Resonator - droning now gone. But Alfa back boxes struggling with the level and starting to break - up, become ragg -ed. But at least it confirmed the issue surrounding the drone was related, if not entirely due to the resonator. However, having a spare Alfa twin cat, I long had my suspicions about that too!
Cue - New rear boxes. Dear me! An explosion of noise, filthy, scrambled noise and God, the level! But at least it confirmed my suspicions about the Alfa Cat. It can heard producing spurious products across the "Reed", which is formed by the way Alfa have crushed the twin cat outlets into one.
I reasoned, at low revs, the gas velocity across the Reed is sufficiently low to generate sound, similar to the way a clarinet. does. But in this instance, the two pipes join tangentially and where they Siamese, the edge is badly burred. Of course the capillaries of the two cats make it worse as they linearize the flow before the reed.
Cue - Supersprint Catalytic Converter. I have about three more weeks to wait before delivery. However the two headers will co-join; via the Flexis, at the input to this new cat. So it should help improve scavenging which Colombo Bariani Camshafts create, and the Autodelta Headers assist.
The camshafts alone, create 23.5 deg. of PVO, and how many carburettor-ed or Port Fuel Injected engines does anyone know, that can idle rock - steady at 750 rpm with that amount of valve overlap?
With the S.S. Cat, I expect the exhaust gases to be a lot cleaner - acoustically going into the S.S. centre section. However, I suspect the level to the new rear boxes will increase further and instead of waking the dead in Moscow, they will hear me coming in Beijing!
Solution - I really don't have one at the moment. The car drives like it has just shed 400 kilograms and above 3000 rpm it is glorious. At 4000 rpm, she is going like a missile - my wife complains it hurts her neck. There is no pleasing some folk! So whatever I do, I don't want to lose that.
Once, if, when, I get this sorted, I will need a new pair of rear tyres. They were new, less than 3000 miles ago. But there isn't much of them left now!
P.S. - Once the S.S. Cat is fitted and I doubt my problems will end there, I am going to try this device from Jetex Exhaust Systems - U936330, inserted into the S.S. central section, just before the "Y" which feeds the two back boxes. But I don't hold out much hope! Could be just snake - oil!
Quoting my own words from the previous post:-
"The camshafts alone, create 23.5 deg. of PVO, and how many carburettor-ed or Port Fuel Injected engines does anyone know, that can idle rock - steady at 750 rpm with that amount of valve overlap?"
I do so, as an indication of what Alfa did not realise they had. And Colombo Bariani will supply even more aggressive cams - specially manufactured - should I want them.
The point being, only cool, fresh air is ingested at tick over; or when "lifting", as the fuel is Directly Injected at ~ top dead centre on the compression stroke. So even with a massive overlap - even by competition standards, there is no risk of fuel detonation in the manifolds or backfiring through the inlet tracts and even less risk of a crank - case explosion.
Again, I attribute the VVT system to Ferrari. And had Alfa marketing men not being attempting to create a "White Elephant", someone would surely have realised the potential of this engine.
If Chrysler can simply modify the design; just a little - refine if you like, such that it will still be in production until 2026; and just consider for a moment the size of their market share, it surely warranted more consideration. And the Chrysler is up to four litre capacity!
The bore/stroke ratio of the 3.2 JTS is pretty much on the money and when my 159 failed, the only comment it illicit - ed was, "It just did not want to stop - there was no flat spot." This was at 7200 - 7300 rpm.
It may not be an Alfa Engine. But it is in every way, in the spirit of an Alfa Engines!
BTW -- what is that "Powered by Holden" badge stuck to, anyway?? An Elfin??
The last vehicle I saw carrying this message was the local version of the Bedford CF van.
Quote from: sportiva on August 02, 2020, 07:28:27 PM
wow! you can wear out tires/tyres in less than 3k Miles or 4.8k kilometers
and you haven't been arrested you are very lucky.
Not really been hitting high speed, more checking on acceleration. Seems P Zeros are quite hard when new, but once you get beyond new, they seem to dump rubber very quickly. Well that's my experience with them on my GTV. In fairness, I think I can coax another couple of thou if I am not too silly. But this damned exhaust problem is really grating. I really think I screwed up on the back boxes.
But I do like the idea of that badge and the van connection. Farina badges used to be on Austins; A40? if I remember correctly.
From the various articles I have read, the Holden/Chrysler versions had a smaller advance retard angle, 35 deg. seems to ring a bell. Whereas the Alfa VVT system is a full 50 deg. And some variants of the Vauxhall and SAAB 2.8 only have VVT on the inlet camshaft. Something Alfa did with the Variator on the 156.
Authorities have said, 85% of the improvements made with quad cam systems can be achieved by just changing inlet camshafts. It is inlet valve timing that is more critical. It thus follows, similarly, fitting VVT to just inlet camshafts will have a similar beneficial effect.
Also, when one looks at the rotors, the Alfa timing plate is much more sophisticated, less crude. Well that is no surprise, because when researching the position sensors of the VVT system, it transpires that it is exactly the same as Bosch used when developing their "Hall effect" devices.
The signal detected by the sensor is very small and there is considerable noise surrounding it. To minimise noise, part of the VVT rotor - the collar, is alloy, in an effort to keep the actual rotor's noise footprint out of the signal. And because it is such a small signal, to help differentiate it from noise, as much metal is cut away from the sensor plate to isolate the signal, as much as possible from the rotating sensor plate superstructure - which is ferrous. Hence the slots!
The hall effect signal is pseudo - triangular shaped, with a fair bit of noise sitting on it naturally. So when processing it to a form which the ECU system can use, it is amplified, then filtered to remove this noise; then amplified again.
It then drives a very precise "Zero - Offset Schmitt Trigger". Because it is triangular wave, both the positive going leading edge and negative going trailing edge, of the signal, will cut the "Schmitt - Threshold" at exactly the same level. The net effect is to produce a square wave output waveform, which has both a very fast rise/fall time and is accurate wrt timing within the context of the timing of the ECU.
If the signal is low, then the Schmitt Trigger can ultimately fail to trigger or indeed simply trigger late and introduce a error which in the extreme can lead to a code failure for cam timing; rear bank exhaust sensor as a case in point. This also has a bearing on the front bank manifold cat and cylinder head overheating issues - but that is another story.
As pointed out earlier, unless the sensor is correctly fitted, the amplitude of the triangular wave quickly diminishes. And Bosch state, the field generated by the rotor plate should pass the sensor face at a right angle +/- 0.5 deg.
So the rear bank sensor is incorrectly fitted to the 3.2 JTS. This probably came about because the panels were cast when there was no VVT fitted to the exhaust camshaft.
However, with regard to Ferrari's involvement, it is my belief that the software control for the system and hence the ECU program is likely to be theirs. It is too good for Alfa to have come up with it - in my opinion.
Quote from: sportiva on August 03, 2020, 03:55:54 PM
And to keep on topic at least the GM designed partially built? Holden V6 engine is of a 60° angle. not many V6's are 60° simply because most V6 cars over the decades were run down V8 production lines so a 90° V6 was just cheaper and easier to do. Even the Ferrari influenced V6 in the new Giulia is a 90° configuration.
Interestingly the "Ferrari-built" (using a U.S. cast block) Maserati Ghibli V6
is 60 degrees.
https://r.search.yahoo.com/_ylt=AwrJQ5ylzCdfV2UAaDEM34lQ;_ylu=X3oDMTByaW11dnNvBGNvbG8DaXIyBHBvcwMxBHZ0aWQDBHNlYwNzcg--/RV=2/RE=1596472614/RO=10/RU=https%3a%2f%2fwww.cycleworld.com%2f2013%2f08%2f01%2ftechnical-analysis-90-degree-v-four-engine-motogp-racing-technology%2f/RK=2/RS=3o75W9dXdmr8qpomHXr7F5mvFng-
Here's that name "Jano" again!!!!!!!!!!!!!!!!!!!!!
https://r.search.yahoo.com/_ylt=AwrJQ57WzCdfBhUA5B4M34lQ;_ylu=X3oDMTByMWk2OWNtBGNvbG8DaXIyBHBvcwMyBHZ0aWQDBHNlYwNzcg--/RV=2/RE=1596472662/RO=10/RU=https%3a%2f%2fwww.goodwood.com%2fgrr%2froad%2fnews%2f2020%2f6%2fthe-six-best-v6-engines-of-all-time%2f/RK=2/RS=yZdbu0b3F0_YWTRMfjbd12X_UCQ-
Ferrari increased the angle of his V 12 from sixty, by a few degrees to allow better inlet tract flow. Ninety degree V6's have a lower centre of gravity and allows much better inlet manifold design.
I guess the 3.2JTS is like anything else..........good enough for the present requirement and to be superseded as soon as the next iteration is released. If continual development wasn't a requirement, we would all be still driving cars resembling the Model T Ford.
Like all engines, the 3.2JTS was just a stop gap design while the next engine is being developed. The 12V Busso was a fair engine for its day, however very soon replaced by the 24V model. That again was ok until superseded by the improved 3.2JTS. None of these engines, in retrospect, was perfect. They all had their design limitations.
No doubt the 3.2JTS had its limitations. If it had none, it would still be manufactured. Methinks Alfa Romeo / Fiat very soon acknowledged its shortcomings (as would be the role of engineers and accountants) and developed the Multiair system. Certainly a more elegant and efficient way of controlling valve events. The Multiair probably addresses most of the valve event and related hydraulic control issues identified in the 3.2JTS. Makes sense to incorporate the recent advances in high speed mechatronics and general processing grunt.
With regard to the use of Hall Effect devices and signal processing, back in the early 1990's, a local lift manufacturer (who I used to work for!) used Hall Effect devices for velocity and distance measurement. Tested and reliable well beyond 75,000 pulses per minute, the locally developed electronics and supporting software had no issues operating in a very hostile environment. The application was unique however the technology was not. High speed signal conditioning has been around for a very long time and high noise immunity Schmitt trigger technology for nearly as long. Methinks any run of the mill electronic engineer and software engineer at Alfa would have had the expertise to develop the required systems.
Then again, if an elegant solution exists within the group / company, why reinvent the wheel.
I can't agree with your analysis, it is a little too sympathetic towards Alfa Romeo and neglects the fact that they continually sit back and allow the field to get ahead of them. And the Multi - Air is no substitute for a 3.2 V6.
That Chrysler are keeping this engine; with some re - engineering work, in production until 2026 demonstrates Alfa failed to grasp the point about it's potential when it hurriedly dropped it, and the 159/Brera. Particularly after all the fanfare!
The GT only came to market because there was no replacement car available after the success of the 156 - again another car they dined out on, well beyond it's sell by date. The GTA stretched Busso's masterpiece to 3.2 litres in an attempt to keep the market interested. An illustrious title given to a dressed - up, "Buy One, Get One Free" front wheel drive car which should have been replaced long before it finally ceased production.
The company makes no mention of the fact that Busso' masterpiece was seen as a history, Busso having left the company two years, before Alfa thought to introduce it. Why? Because the new crop of management, and engineers simply carried on as before, sitting on their hands, not really having any idea how to move the Marque forward.
When the Busso adopted four valves per cylinder, it was for technical reasons surrounding emissions. They would just as soon have not bothered. But legislation left them no option. Yet again, they didn't think they needed too.
It was not for technical reasons the 3.2 JTS superseded the Busso, it was financial - pure and simple. Fiat were in financial difficulties, they wanted to close Arese and they were negotiating to climb into bed with another lame duck.
So the 3.2 was a Wedding Present. Albeit, a bit tacky! So they felt they needed to dress it up a bit. And failed miserably. The Platform of the 159 is superb, cost 2 billion in development and it too went the way of the Dodo.
Not what one could call commercial sense for a Prestige Marque, to leave itself without a flagship model for so long.
The history of the Holden V6 is quite convoluted.
The design concept owes much to Ford's Duratec V6 with its primary engineering input coming from Porsche. The engine subsequently finding its way into Jaguars amongst others.
When the development team was broken up, fortuitously it found itself being substantially reformed under the Chrysler Banner. There are still elements of the Holden/Chrysler V6 covered by patents held by Porsche. So it is not without Pedigree!
The 3.2 JTS certainly has it's limitations. But none that Alfa Romeo Identified. However, they certainly added a few of their own! And still we are without a true Alfa Engine. The 2.9 belongs to Ferrari. After a litany of engineering disasters, spanning decades, it is inconceivable Alfa could have pulled this gem out of the hat like a rabbit.
With regard to Hall Effect, it was discovered by Edwin Hall in 1879 but little was done with it for many decades. For me, it is not new technology, but certainly not old. Stability was never very good in the years Valve Technology held sway, the era I hail from. With the advent of semiconductor technology; yet still discrete components, things got a lot better. And microprocessors now enable such technology to be employed in everyday devices.
Impedance Modulation was well understood as a method of increasing Broadcast efficiency, beyond what was thought to be theoretically possible. However, the man who invented it was long dead before component tolerances in manufacture made it possible to produce very efficient transmitters in the 1980's. And companies such as Bosch, can explore and develop technologies, the study of which lie in the vaults of many University Research Libraries.
I stand corrected - apologies for that. Senior moment kicking in!
However, I wondered why a block with such obvious strengths found its way into this engine? Even one Company Director, who gets considerably more from this engine phoned me to acknowledge its obvious virtues, having only just properly inspected it for the first time. Yet it is roundly condemned here in the UK, but no one seems able to give factual reasons for such an overtly negative view.
From a personal perspective, I had no problem with the 3.2JTS in my 159. Apart from needing to replace spark plugs not long after purchase as the car still had the originals after 70,000klms use, nothing of note to mention. Then new plugs every 30,000klm. Also always replaced engine oil and filter every 7500klm. Always fed it 98RON.
Sounds like a recipe for longevity. I doubt that too many in UK go to that length - regardless of Marque!
The Brera engine I rebuilt was run dry at about 40 - ish k. Many car owners do not change their oil and filter often enough, let alone have them properly maintained.
As a lot of cars are bought on Personal Finance Plans, I suspect their servicing schedules run along the lines dictated by the dealerships they bought them from, never thinking that the intervals are perhaps not best suited to every car. Meaning - some owners are thoughtful about the way they use their cars, others may not be.
So, buying on the secondhand market can be a bit of a minefield.
Quote from: sportiva on August 02, 2020, 04:04:06 PM
The old AlfaSud plant were the last 159 was built is very close if not next door to the aviation division.
I acknowledge and understand the history of the two plants and the radial engines alfa romeo built under the leader ship of Ugo Gobbarto were splendid examples of engineering.
The travails of this Enigmatic car continue! To be fair, it is not of Alfa's making - damn. It has more to do with the way I chose to modify my car. The manifold cats have gone. They are the metal type and clearly can withstand much higher temperatures. Although I knew the twin cats below the car are Ceramic and thus lower temperature, I felt as they are some distance away from the engine, they would probably cope ok. It was the output of the twin cats that appeared to be the problem as they form a "Clarinet Reed" for the gases exhausting into the central section where the resonator is. After my modifications, the higher power level was causing extreme droning @ ~ 2500 rpm.
I fitted a Supersprint central section which has no resonator and sure enough, the drone disappeared. But this resulted in a cacophony of noise emanating from the rear boxes. Cue new rear boxes - a lot worse, although both the sound and acceleration from 3000 rpm is brilliant. But impossible to live with at below.
My worst fears seemed to be confirmed - a new cat would be needed. And Supersprints is not cheap. So having bitten the bullet, contacted Supersprint Technical Department. By this time, the Cat had been ordered, but I had the daunting prospect of having to buy yet another pair of rear boxes as the new ones seemed incapable of handling the power. I wanted Supersprints assurance theirs, which would complete my system once the cat is installed, would handle the extra power. I quoted a figure of 350hp as a target figure. I even picked up a brand new Alfa Nearside Box cheaply, fearing I would end up going back to theirs. It confused me, the Alfa boxes handle the lower revs well, but break up at higher revs, the new ones handle higher revs, but break up at lower ones.
I needed Help.
That's where S.S. tech dept. came in. I laid it out as baldly as I could and within the space of the weekend I had a comprehensive reply.
"It's not your rear silencers that are your problem, it's your cat". Brilliant, so at least I had a second opinion supporting my view about the Alfa Twin Cat".
But not for the reason I believed. Quote:- "I would be very surprised if there are any cells left in them". They are 500 CPI (Cells per inch) and very restrictive.
So to shorten a long story, having a spare twin cat in the garage - which I was intending to take to the dump - I got a garden chair to sit on, a 10mm. piece of stainless pipe, an eight pound club hammer and drove the pipe through the cat. Initially it was very reluctant but eventually smashed my way through. A quick check below and sure enough, there were pieces of the Ceramic Cat on the garage floor.
I picked up, what clearly had been part of the outer matrix, which was very hard. The initial strength must have been this outer screen/matrix. However, along with it on the floor was part of the inner honeycombe. Inspecting that revealed it was almost of a dust consistency - extremely crumbly. One could rub a small lump between two fingers and it quickly fell to dust/coarse powder.
So, full marks to the Supersprint tech guy for pointing me in this direction. I don't think the "Reed" helps, but if my twin cat has collapsed cells, it certainly would contribute to my problem.
Funnily enough, after a quick blast to get out into mainstream traffic flow, from a junction yesterday, the exhaust system appears to have got a little less "Rackety". It's not the way it should be. But it seems a bit quieter. And although my doubts about my new rear boxes remain, the throttle response is such that, blipping the throttle a little on down shifts brings an exhaust note that reminds me of my old twin cam Berlina and her Dellorto carburettors.
Funny - the tricks the mind can play on perceptions!!!!!!!
Quote from: Ascari32 on August 25, 2020, 07:22:42 PM
Quote from: sportiva on August 02, 2020, 04:04:06 PM
The old AlfaSud plant were the last 159 was built is very close if not next door to the aviation division.
I acknowledge and understand the history of the two plants and the radial engines alfa romeo built under the leader ship of Ugo Gobbarto were splendid examples of engineering.
The travails of this Enigmatic car continue! To be fair, it is not of Alfa's making - damn. It has more to do with the way I chose to modify my car. The manifold cats have gone. They are the metal type and clearly can withstand much higher temperatures. Although I knew the twin cats below the car are Ceramic and thus lower temperature, I felt as they are some distance away from the engine, they would probably cope ok. It was the output of the twin cats that appeared to be the problem as they form a "Clarinet Reed" for the gases exhausting into the central section where the resonator is. After my modifications, the higher power level was causing extreme droning @ ~ 2500 rpm.
I fitted a Supersprint central section which has no resonator and sure enough, the drone disappeared. But this resulted in a cacophony of noise emanating from the rear boxes. Cue new rear boxes - a lot worse, although both the sound and acceleration from 3000 rpm is brilliant. But impossible to live with at below.
My worst fears seemed to be confirmed - a new cat would be needed. And Supersprints is not cheap. So having bitten the bullet, I contacted Supersprint Technical Department. By this time, the Cat had been ordered, but I had the daunting prospect of having to buy yet another pair of rear boxes as the new ones seemed incapable of handling the power. I wanted Supersprints assurance theirs, which would complete my system once the cat is installed, would handle the extra power. I quoted a figure of 350hp as a target figure. I even picked up a brand new Alfa Nearside Box cheaply, fearing I would end up going back to theirs. It confused me, the Alfa boxes handle the lower revs well, but break up at higher revs, the new ones handle higher revs, but break up at lower ones.
I needed Help.
That's where S.S. tech dept. came in. I laid it out as baldly as I could and within the space of the weekend I had a comprehensive reply.
"It's not your rear silencers that are your problem, it's your cat". Brilliant, so at least I had a second opinion supporting my view about the Alfa Twin Cat".
But not for the reason I believed. Quote:- "I would be very surprised if there are any cells left in them". They are 500 CPI (Cells per inch) and very restrictive.
So to shorten a long story, having a spare twin cat in the garage - which I was intending to take to the dump - I got a garden chair to sit on, a 10mm. piece of stainless pipe, an eight pound club hammer and drove the pipe through the cat. Initially it was very reluctant but eventually smashed my way through. A quick check below and sure enough, there were pieces of the Ceramic Cat on the garage floor.
I picked up, what clearly had been part of the outer matrix, which was very hard. The initial strength must have been this outer screen/matrix. However, along with it on the floor was part of the inner honeycombe. Inspecting that revealed it was almost of a dust consistency - extremely crumbly. One could rub a small lump between two fingers and it quickly fell to dust/coarse powder.
So, full marks to the Supersprint tech guy for pointing me in this direction. I don't think the "Reed" helps, but if my twin cat has collapsed cells, it certainly would contribute to my problem.
Funnily enough, after a quick blast to get out into mainstream traffic flow, from a junction yesterday, the exhaust system appears to have got a little less "Rackety". It's not the way it should be. But it seems a bit quieter. And although my doubts about my new rear boxes remain, the throttle response is such that, blipping the throttle a little on down shifts brings an exhaust note that reminds me of my old twin cam Berlina and her Dellorto carburettors.
Funny - the tricks the mind can play on perceptions!!!!!!!
For me, "Enigmatic"remains the term most applicable to this car, but more specifically the engine. It is difficult, without access to full workshop facilities to move anything along quickly - automotively - a local exhaust fabricator is fully booked up until November and I await my Sports Cat with baited breath.
In the mean time, I have been ploughing through E.U. Research Documents on Emissions, Manifolds, Catalytic Converters, Diffusers, Resonators and Silencers/mufflers.
One document is 317 pages long. It covers these areas scientifically but seems to be directed at guidance for car manufacturers in a manner, which allows scope to develop their own unique way of resolving emissions issues. Compliance being the critical point. How it is achieved is up to individual car makers.
Catalysts however, remain mandatory!
But there are many ways of skinning a cat! And it appears to me, it gets to a point when ultimately car manufacturers apply economics to solutions in a manner which cannot be sustained from one generation of cars to the next. I wonder if the drive towards electric would have been so fast, had not motor manufacturers applied more of the known science to getting emissions under control, than they have hitherto.
Which brings me back to the engine which I term "Enigmatic". So little is given away by manufacturers, with regard to their motives for adopting x,y or z approach to problems which are common to virtually all cars. OK, specific perhaps in the sense they are diesel or petrol driven, but common wrt either type.
And so I return to the issue of valve timing in respect of the 3.2 JTS. If anyone has further expert knowledge or insight into this issue, I would appreciate their views. It certainly would be a lot easier than having to pull together all the specific research contained in 317 pages into one concise document. Trying to determine the interrelationship between such complex areas is hard work. However, I think I have; courtesy of such documents, stumbled upon another reason for Alfa's choice of valve timing, in particular the exhaust valve timing.
Not only would it appear to be their method of generating "Internal EGR", it may also be intended to reduce "Reverse Flow" through the Catalytic Converter Element. By closing the exhaust valves at such an angle, it probably reduces any depression pulling gases back into the cylinders, thus slowing gases through the cat or indeed causing reverse flow. I am still working my way through this one.
However, one thing I am absolutely certain of is the second feature of closing the exhaust before the inlet opens. There is little point in fitting manifold cats in an attempt to maintain "Light - off", which enables Catalization, if valve timing allows cross-flow between inlet to exhaust - PVO - which would in effect cool the Catalytic Converter down!
Somehow, it all seems to have got lost in the mix for Alfa. It is Paradoxical for a company whose History is founded upon a "Racing Heritage" to apply such contradictory principles to cars such as the Brera and 159 and claim they continue this into the modern era.
As flawed as they are, the 147/156 GTA's are more in keeping with that ethos than these two models. Even the base model 147/156 can be tweaked by enthusiasts, in much the same manner as Berties, Berlina's and Spiders were. And it wouldn't cost a Kings Ransom.
It's a shame, given the 159 and Brera are both fine cars. If only Alfa had not gone so far in strangling the life out of the engines for the sake of fickle legislation, which so often changes due to "Woolly Headed Bureaucrats". The 3.2 JTS would comfortably made 280 BHP and could still have met emissions regulations had they really wanted to maintain their sporting image. I calculated, the Q4 would need to be 286 BHP to match the 156 GTA. Front wheel drive versions would have bested it!
Wasted opportunities. And now we all need deeper pockets to afford Alfa's.
The Supersprint catalytic Converter has now been fitted to my 159 for about two - ish weeks. The Alfa boxes cope very well and it generally sounds very sweet, with no popping or farting on overrun. Just a good solid "Blat". But it still did not feel entirely right.
At the same time as the cat going on, a failed rheostat was found and a replacement ordered. I thought I was faced with a very big bill for the climate control system; but no, the guys picked it up very quickly and temporarily the A/C is working.
Although not quite feeling right, I believe when the rheostat is replaced, i will refit my new boxes again. I think that is only fair, before I consign them to the scrap heap/ebay. Prior to the S.S. cat going on, I was experimenting with different fuel grades, provoking management codes at will when swapping from RON 95 to 97. However, I had not cleared the codes when the cat was fitted.
Subsequent to this, I disconnected the MAF, wondering if the slight lack may be due to the MAF, but no change. So I went and saw the guys and asked if they could just give the history file a once over and reset the alarms for me. There was a fairly substantial log to be cleared, all relating to Lambdas and MAF with a couple of cylinder misfires in the mix.
Since the log has been reset however, that slight niggle about performance has evaporated. The engine is running beautifully. Silky smooth at low rpm and what is particularly noticeable is how smooth it is when pulling away and changing up. First and second have always been "Notchy" and not getting it right, the the revs would die off very quickly. Getting my timing right between first and second was crucial. But, because there is now so little drag on the engine - the engine gently dies - off the revs; as I dip the clutch, move from first to second and the re - engage. It really seems like a different car. Progressively it gets better 2nd to 3rd, 3rd to 4th. And fifth and sixth have never been a problem.
Acceleration is strong, with no flat spots, revs rising very quickly, the car belying its weight. Exhaust, very throaty at low revs but I do miss the sound it makes with my new boxes over 3000 rpm. Not bad though and the Alfa boxes coping well. Noise levels are very acceptable - nothing like the original but acceptable. Tick - over solid but meaty. I cannot see that when the new boxes are refitted, it will be any quieter. So that mat be the sticking point. But it is worth a try.
I shall have the front drivers side wheel bearing changed at the same time as the rheostat is done as that is the only untoward noise coming from the car. All in all, I love it. Next stop - heart in mouth - Dynamometer. But I will wait a couple of weeks, just building up the courage. That aside, what a fabulous car the 3.2JTS Q4 is - now!!
Quote from: Ascari32 on October 10, 2020, 09:42:10 PM
The Supersprint catalytic Converter has now been fitted to my 159 for about two - ish weeks. The Alfa boxes cope very well and it generally sounds very sweet, with no popping or farting on overrun. Just a good solid "Blat". But it still did not feel entirely right.
At the same time as the cat going on, a failed rheostat was found and a replacement ordered. I thought I was faced with a very big bill for the climate control system; but no, the guys picked it up very quickly and temporarily the A/C is working.
Although not quite feeling right, I believe when the rheostat is replaced, i will refit my new boxes again. I think that is only fair, before I consign them to the scrap heap/ebay. Prior to the S.S. cat going on, I was experimenting with different fuel grades, provoking management codes at will when swapping from RON 95 to 97. However, I had not cleared the codes when the cat was fitted.
Subsequent to this, I disconnected the MAF, wondering if the slight lack may be due to the MAF, but no change. So I went and saw the guys and asked if they could just give the history file a once over and reset the alarms for me. There was a fairly substantial log to be cleared, all relating to Lambdas and MAF with a couple of cylinder misfires in the mix.
Since the log has been reset however, that slight niggle about performance has evaporated. The engine is running beautifully. Silky smooth at low rpm and what is particularly noticeable is how smooth it is when pulling away and changing up. First and second have always been "Notchy" and not getting it right, the the revs would die off very quickly. Getting my timing right between first and second was crucial. But, because there is now so little drag on the engine - the engine gently dies - off the revs; as I dip the clutch, move from first to second and the re - engage. It really seems like a different car. Progressively it gets better 2nd to 3rd, 3rd to 4th. And fifth and sixth have never been a problem.
Acceleration is strong, with no flat spots, revs rising very quickly, the car belying its weight. Exhaust, very throaty at low revs but I do miss the sound it makes with my new boxes over 3000 rpm. Not bad though and the Alfa boxes coping well. Noise levels are very acceptable - nothing like the original but acceptable. Tick - over solid but meaty. I cannot see that when the new boxes are refitted, it will be any quieter. So that mat be the sticking point. But it is worth a try.
I shall have the front drivers side wheel bearing changed at the same time as the rheostat is done as that is the only untoward noise coming from the car. All in all, I love it. Next stop - heart in mouth - Dynamometer. But I will wait a couple of weeks, just building up the courage. That aside, what a fabulous car the 3.2JTS Q4 is - now!!
P.s. The feeling of having lost a little at the bottom end has now gone, with good solid torque coming in, low down Always better than standard, it just seemed in the process of trying to resolve my exhaust/cat problems, a little was lost in the mix. Now, back to what it was - absolutely fine. Hope that feeling wasn't down to my new boxes. However, I will find that out when I refit them!!!
The Saga goes on - and on - and on!
Ascaris now History although they have been useful in trying to resolve the exhaust issues, which I believed were at an end.
The Standard 3.2 JTS has valve timing such that the engine is 11.5deg. into its induction stroke before the inlet valve opens, the exhaust valve having closed 3.5deg. earlier. Thus there is no crossflow - air passing from inlet to exhaust. So the velocity of air in the inlet tract is interrupted, if not completely halted.
As a result, it is difficult to see how good volumetric efficiency can be achieved. Also, this means the ECU has a less time to calculate the Air flow upon which it can meter the fuel injection. So; by my reasoning, Alfa needed to fit a MAF with a very fast rise-time; dr/df transfer characteristic - a steep slope, to enable the ECU to read Peak Airflow very quickly.
Unfortunately, when fitting the Colombo Bariani camshafts, which have a 23.5deg. valve overlap, the increased air flow, - crossflow element+cylinder fill results in the ECU setting AFR which is too rich. The obvious consequence of this is the powerful/meaty exhaust sound, even though the engine is at 750 rpm - solid: and rich operating conditions overall.
So logic suggested, a MAF with a different Transfer Characteristic is needed. I tried a new 916 GTV 2.0 version - (2) on the attached data sheet - and there was a good improvement at the lower end with a more subdued tickover. But it's range is too low and it topped - out at 4500 rpm, which tied up with Bosch's data sheet.
I then tried the new MAF from my 3.0 GTV - (3) on the attached data sheet - which clearly has a higher flow rate and things really did improve dramatically. So much so, that I was able to "Trim" the output signal with resistance values the original 3.2 JTS MAF would not tolerate.
This was where the Ascaris became invaluable. Small changes in the "R" - values were immediately reflected in a change in the character of the exhaust sound emanating from the Ascaris. Indeed, the character of the exhaust became that much more harmonious, acceleration seemed sharper to the extent that it seemed like major changes had been made and not just changes to (R) values. I eventually settled for 600 ohms, nearly three times that of the test values used when trying to understand the problem with the original JTS MAF.
At this point, I decided to stop as I had already booked the car in for the Alfa Boxes to be refitted. During this period, I was searching for a MAF which would give me a less acute transfer characteristic and the only one I could find, which was a HFM 5 was the 911 Porsche 2.8L. My logic being such that, a turbo car would require a lower/less acute transfer characteristic. But needless to say, that is expensive. An alternative; I thought, could well be (5) on the attached data sheet, but that is very difficult to find - I have seen it, but at Mega Bucks.
Happily, I found version (4) on the data sheet which is used on some Volvo models. It's transfer characteristic follows a similar profile as (3), but with a higher airflow limit. I am hopeful that I can also trim the dr/df transfer characteristic to give an optimum AFR characteristic.
Although not as precise as the Bosch method - which is why the covers on these sensors are sealed with a gasket enabling the makers to calibrate the response to any car makers requirements - it would require test facilities which are beyond me. But, it isn't entirely crude and should enable me to adjust fuel metering to a greater degree of accuracy than with the JTS's standard MAF. Indeed, were I to fit a vernier resistive network and quality AFR gauge, it would be possible to trim fuel continuously on long journeys.
Alas, whilst standing in the workshop as Adam drove the 159 into the bay, with the Ascaris, it finally sounded absolutely glorious. Nothing like it sounded from the driver's seat. So I suppose it must be down to acoustic coupling. Either way, they will go on eBay or to the dump. The Alfa Boxes are back on now, but they have benefited from the ability to set the current loop of the MAF when the Ascaris were fitted.
The Bosch 0280218008 MAF should be here in a week or two and the exercise of trimming the loop again will be done with the Alfa boxes insitu - I hope they are as responsive enough to find the sweet spot as it was with the Ascaris.
Torque seems a little stronger below 1500 rpm and beyond she just comes on strongly, but with less audible drama which I got with the Ascaris. If only I could have made them work! Above 3000 rpm, they are in a league of their own!
Quote from: sportiva on August 02, 2020, 08:08:16 AM
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA :)
Lets be clear - Alfa took the small bore GM block and developed their own variable multivalve heads for it. A former colleague was a design engineer at GM Elizabeth at the time and he said when the first units were shipped back to GM Oz for review the engineers complained that Alfa had done what they had not been able. SIDI was a result or Alfas work.
People get misty eyed over the Busso but it could not meet EU emissions compliance so naturally Alfa had to cast about within GM and come up with a solution.
Comments re 600HP out of the engine? Seriously? Its well known that the AutoDelta SC kit boosts HP but at the expense of the transmission. So there is NO WAY that you can put down 600HP in that 939 Series configuration without major rework of the entire driveline.
I would like to know what exactly what it was Alfa did that GM could not? From my studies of the both Brera and 159 engines, Vauxhall and SAAB, there is no difference in the architecture of the Block.
Whereas Alfa of old would have cast swage/baffle plates into the sump and certainly not returned oil from the heads in miniscule amounts, down cavernous channels, such that it appears in the sump at a level, and exactly in - line with the rotating Crankshaft Journals, to be immediately whipped into windage.
Neither would they have failed to see, the windage plate(s) does not extend along the full length of the sump, exacerbating "Slosh" - for want of a better term. The second plate was a latter addition by GM I am informed. Nor would the fact that the oil pick - up in the sump sits too high above the sump floor and is readily exposed if oil level are not scrupulously maintained, when lateral forces shift the oil in the un-swaged/baffled sump, have gone un - noticed.
Or that the sump was too small for the amount of oil in circulation to be healthy - deigned around a 4 litre capacity with 1.8 litres in circulation. This is a figure before the addition of VVT's on all four camshafts.
I had no interest in GM engines prior to my 159. However, these failing firmly belong to GM. So much so, that the latest incarnation of this engine; which is planned to be in production until 2026, incorporates modifications to rectify these issues.
My studies began with a wrecked 40,000-ish miler Brera engine [oil starvation] and only developed into a full-scale project when my 159 engine failed - on a parabola, with a full sump of new oil and a new oil filter. So a detailed exercise was undertaken - I was not simply going to replace what Alfa had served up to their customers. It is not being unkind to say, amongst UK Alfa enthusiasts this engine is very poorly regarded - being polite.
I can understand any sense of pride having a GM engine in and Alfa would generate for you guys. I hold the block of this engine in very high regard. It is incredibly strong and I have been reliably informed it is good for 600 BHP, but I'm not aware that it is in an Alfa 159 or a Brera. It is alleged the limiting factor with Autodelta is fuel delivery.
Having been a continuous owner of Alfa's, to the exclusion of all other marques for almost forty years, I can only think their engineering department has become so depleted that they didn't even bother about looking at the issues I have alluded to above, simply choosing to focus on reworking the Heads.
But it is generally accepted in engineering circle, it is not a good idea to have a single oil pump provide for all the needs of such a complex engine. Or, have the most fundamentally important component - lower timing chain tensioner - at the very end of the oil supply system. Or to deplete it's oil supply even further by having "Leaky VVT Solenoids". Or, fail to read the data, Bosch go to great length to supply and ensure, all four camshaft positional sensors are correctly aligned, choosing to use a boss on the front cover simply because it saved them from re-casting it in the correct orientation. The front bank inlet and exhaust sensors, plus the inlet sensor of the rear bank are perfectly aligned. The rear bank exhaust camshaft sensor is not. Bosch quote +/- 0.5deg. off - axis limit. So it is hardly surprising it is always, to my knowledge, the rear exhaust cam which flags a code for camshaft timing error!
Furthermore, there are four serious restrictions, cast within the block, which are difficult to overcome, without supplementary oil feeds. I believe, the latest incarnation overcomes these, but unless I get my mittens on one, cannot swear to it. The JTS system is a brilliant concept but Alfa failed to grasp the niceties of making it work - properly. There was pressure on them to introduce a replacement for the Busso. As a result they seemed to have incorporated a lot of the research work being done in an E.U. funded study. The study was intended to give guidance on emissions and although many aspects were investigated, it was intended for guidance. All manner of techniques were investigated, not all of them intended to be used in the same package, I believe. But Alfa chose to use a lot more than deemed necessary. They achieved a top rating for the engine when it was released. But very few have stood the test of time. In fact they are becoming an incredibly rare sight.
The Busso remains a brilliant benchmark engine. I have a low mileage 3.0 litre GTV. But the 3.2 JTS is, when all the encumbrances are removed and it is allowed to work properly, is more than a match for it.
However, the Busso, will remain the last truly great Alfa Romeo engine, Designed and Built in - house by one of the greatest Automotive Engineers that lived. The longevity of its production run alone speaks volumes and I do not know of a single V6 that does not owe it's design to some aspect of what Busso achieved.
The 3.2 JTS engine had what must have been the shortest of production runs in the automotive industry, let alone with Alfa. I doubt there will be many to be found in a few short years, such is its reputation. Whereas, the Busso will go on and on, as long as there are Alfa Romeo enthusiasts in the world. And I predict it will command high prices. One can pick up a 3.2 JTS for £200.
Despite this, I have an extremely high regard for this engine, once its issues have been addressed.
Quote from: torquemeister on November 14, 2020, 06:43:58 PM
Quote from: sportiva on August 02, 2020, 08:08:16 AM
Found a badge ;) for your car that was assembled in Pomigliano d'Arco by F.I.A.T SPA :)
Lets be clear - Alfa took the small bore GM block and developed their own variable multivalve heads for it. A former colleague was a design engineer at GM Elizabeth at the time and he said when the first units were shipped back to GM Oz for review the engineers complained that Alfa had done what they had not been able. SIDI was a result or Alfas work.
People get misty eyed over the Busso but it could not meet EU emissions compliance so naturally Alfa had to cast about within GM and come up with a solution.
Comments re 600HP out of the engine? Seriously? Its well known that the AutoDelta SC kit boosts HP but at the expense of the transmission. So there is NO WAY that you can put down 600HP in that 939 Series configuration without major rework of the entire driveline.
Let's also be clear about the pedigree of this engine. The team that developed the V6 engine for Ford/Jaguar had been broken up when the project ended. Porsche were heavily involved with it, to the extent they still hold patents on elements of its design. Ex - members of the team became involved with the new engine GM wanted develop, in which Holden also played a part.
It is a testament to it's design that Alfa chose to use it, but to be honest they were over a barrel given their engine plant was being closed. So in essence, to claim it as their own, and given the reputation the Busso had, it had to be radically different. However, the block is a modular design, in this instance specified as 3.2 litre. But it is not true they developed/modified the block further. The heads yes, with all components already available on the market - V.V.T's included. So apart from recasting the heads, little design work went into the Alfa 3.2 JTS.
To add to the woes the lower timing chain tensioner suffered was the spray jets which bleed oil from the main gallery and further reduce the supply to the tensioner. Not only that, they are low pressure and are known to jam open, allowing the block to bleed down when the engine is switched off.
Oil pressure in the Vauxhall 2.8 Insignia turbo, the Opel and SAAB turbos, do not suffer quite so badly as an extra oil feed is taken from the Oil Cooler/Filter housing to the turbo. There is a "Boss" on the Oil Cooler/Filter housing, which is left undrilled on the Alfa.Had Alfa thought more seriously about how to make the VVT's work properly, not to mention the rear timing chain tensioner, they would have used this Boss as a supplementary feed for the block. One simple Oil Line would have cured the problem of lower timing chain tension, rear bank upper timing chain tension and balanced the feed pressure for the VVT's on both banks.