Author Topic: 3.2 Q4 modified - outstanding issues.  (Read 1102 times)

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Ascari32

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3.2 Q4 modified - outstanding issues.
« on: August 06, 2021, 02:50:16 PM »
Cosmetically, I stills need to get a grip, polishing and changing the rear plastic light covers. I must also find a new boot lining and rear panel to fit behind the passenger seats.

However, the car has been at the garage for some 10 days now after the clutch failed on a baking hot day. It was recovered by the AA, who said it was the master cylinder which had gone.

It transpires it is the slave - ouch! However, since the engine was rebuilt and back on the road 18 months ago, any warranty on parts would normally have expired. But a new clutch was fitted and since then, the car has only done ~ 10,000 miles.

Bearing in mind this is neither an Alfa Franchise or and Alfa Independent, they could have played it by the book and said I have no claim.

Although not making a claim, just simply wanting to get the car back, when they phoned to tell me it was the slave cylinder, they pointed out they buy a huge amount of parts from this supplier and prevailed upon them to replace the failed part, and pay half the labour costs!

But everyone is catching up on holidays so the repairs won’t be starting till next week.

I continue to run with the Porsche 055 element and it continues to get better and better. So much so, the Ascari boxes are having plates welded top and bottom over the central cavity/resonator sections, to try and stop them breaking up below 3000 rpm. The plates are going to be drilled with a series of holes and puddle welded to increase the rigidity. I am a bit concerned it may cause a single - note “Droning”, but I have to try, before they go into the skip!

I had a problem with the NTC sensor, fitted in the water jacket of the head, close to number two cylinder exhaust port. It was intermittently open circuit, “x/y/z” value, but never actually changed with temperature.

A new one was under £20 delivered and this greatly improved start-up noise reduction. The element now heats up very quickly and on the basis of its changing value, the ECU retards the exhaust camshafts much quicker, causing the valves to open later. This results in much less unburnt fuel being “dumped” into the exhaust manifold - the purpose being to get the cats to light-off quickly.

I however, have Autodelta headers which are cat free. Consequently, this excess fuel creates much more noise than is the case with the man - cats, which “muffle” the noise much better.

The C.B. exhaust cam when fully advanced closes the exhaust valves 23deg. atdc and has a duration of 278deg. So when fully advanced, it opens the exhaust valves at 75deg.. bbdc. 105deg. atdc on the power stroke.

That is very, very, very early, considering the engine is ticking over at 750 rpm. It must still be “super rich in unburnt HC’s”, which continue to burn and cause catalytic action which quickly warms the cats.

But the NTC sensor, being as close as physically possible to the cat, yet within the water jacket around number 2 cylinder exhaust port should heat up quickly to retard the opening angle to somewhere nearer a normal operation one.

Coincidentally, 105deg. is a familiar figure! I seem to remember this printed on the boxes  of the C.B. cams supplied for my Busso 2.5GTV6!!!

Well, well, well - who says it is out with the old and in with the new? If all C.B. have done is transfer the optimum angles for Busso camshafts, which would have limits due to the lack of VVT, to their cams for the 3.2JTS, which does have VVT, no wonder they are “Special”.

I recall, they gave my Busso a very special performance. And like the cams for the 3.2 JTS, were expensive.

“Great Engineering is Timeless”
« Last Edit: August 12, 2021, 12:45:49 PM by Ascari32 »

Alfatango

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #1 on: August 07, 2021, 04:47:52 PM »
Yeah great engineering transcends time. Maybe thats why classics are worth so much now.
159 3.2 JTS TI

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Ascari32

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #2 on: August 12, 2021, 01:54:57 PM »
Alfatango: -

"Maybe thats why classics are worth so much now".

Yes, and no! Classic status comes about not necessarily because something is great. In many instances it is because there are so few left. But on increasingly rare ocassions, time has afforded us the oportunity to look more closely into the design elements, which if they are great, can be seen in modern day itterations. And it is quite natural to reflect upon engineering features/elements that continue to "travel - well".

And if one is lucky enough to have a vehicle that has lots of good engineering elements, is clothed in a body which invariably the wider industry copies and has become rare due to our "Throw - away Mentality", then we are extremely lucky.

That, to me is what guarantees Alfas will always be held in high regard. But that does not mean we should not push Alfa to "Try Harder".

It would however, be more helpful if those who review these cars, understood a little more about them and not just simply take them for the prerequisite test drive and dismiss them for x,y or z failings.

I refer, in this instance to a test of the 159 by good old "Tiff". A cursory drive in an urban environoment and it was dismissed with the obsevation "Oh dear Alfa, what have you done?" He was refering to the 3.2 Q4 JTS.

His particular gripe was the F40 gear box. And while there are reasons for complaint, it was less than helpful not to understand better the reason why it is so "Notchy" in first and second.

All this reflection comes about as my 159 was picked up yesterday after the clutch slave/release bearing was replaced. I have heard from several sources it is an engine out task! Not so, half a days work for a garage which has no association with Alfa. Thanks again to those brilliant guys for looking after me - and my car.

But it is the longest spell I have had without wheels for quite some time - over 3 weeks. It was ready on Tuesday but I decided to have a day with the phone switched off and I missed the call. No matter - all's well that ends well!

However, this brings me back to the F40 gearbox. When I first got the car, first and second gear were extremely "Notchy". Now however, gear changes are silky smooth by comparison. Why, what has changed?

Well, I believe there is a direct connection with the change in valve timing, notably the Colombo Bariani Camshafts. With the original valve timing, the engine revs were "Checked" and this creates considerable drag on the transmission system - a factor which, in my opinion has a great deal of bearing on the timing chain system. This is much more apparent in low gears and I found engaging 1st and 2nd pretty "Ugly". Even so, the braking effect of the engine to me is a reason why the 159 brakes can be viewed as adequate. The combination of engine braking and ABS system works well.

Now however, I hold the view, the brakes just aren't up to the job as the engine is so willing ro "Run - on", when one lifts off the throttle. This also appears to reduce the resistance between the engine and transmission system when changing gear.

Those weeks without wheels were sufficient to forget about how the car felt - not entirely but driving reagularly one takes things for granted. But when one resumes driving, the little nuances become accentuated for a while - until one again becomes so familair to accept them as normal.

And so it was yesterday, when I picked up the car. Adam had interrogated the fault register - nothing out of the ordinary and reset the ECU. So it was nice to have an alarm free dash, although I did not notice it until I had settled onto a country road out of town. The 055 Porsche MAF element it working impecably with really good progression. And that gear change is sublime. The overun is delightful, making the exhaust sound just as pleasant when lifting as it is on acceloration  - no popping and farting.

The engine generates so little drag on the transmission system that my overarching view is the brakes need up - rating!

If good old "Tiff" were to drive my 159, he would be a lot less critical about the gearbox. But I would suspect he would find something else to "Lambast" Alfa about - after all, at the start of his test, he acknowledged he was no particular fan of the Marque.

So why the hell did he review the car?     
« Last Edit: August 12, 2021, 02:02:01 PM by Ascari32 »

Alfatango

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #3 on: August 12, 2021, 08:17:35 PM »
I did ebc blue stuff pads in the front and yellow stuff in the rear and that to me got the best out of the brembo brakes.
159 3.2 JTS TI

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Ascari32

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #4 on: August 12, 2021, 10:31:46 PM »
 Hi A.T!

Is yours a Q4? I need to try something as I am told I will have to go to nineteens to accomodate bigger calipers/discs.

Ascari32

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #5 on: August 13, 2021, 08:02:04 AM »
The volumetric efficiency ηv [-] is defined as the ratio between the actual (measured) volume of intake air Va [m3] drawn into the cylinder/engine and the theoretical volume of the engine/cylinder Vd [m3], during the intake engine cycle.

𝜂𝑣=𝑉𝑎𝑉𝑑(3)
The volumetric efficiency can be regarded also as the efficiency of the internal combustion engine to fill the cylinders with intake air. The higher the volumetric efficiency the higher the volume of intake air in the engine.

In case of indirect fuel injection engines (mainly gasoline) the intake air is mixed with fuel. Since the amount of fuel is relatively small (ratio 1:14.7), compared with the amount of air, we can neglect the fuel mass for volumetric efficiency calculation.

One issue which continues to be outstanding is that of the actual power increase after the modifications to my ex - Brera engine now installed in my 159 Q4.

Accepting all things remain equal, ie. relative as opposed to absolute figures, Improved Volumetric Efficiency and Scavenging -are  both important factors and mutually beneficial to the performance of any naturally aspirated engine.

For the purpose of this article, I shall ignore all physical modifications to the engine.

Firstly, as the exhaust valves no longer close at 9deg. ATDC, but now close at 23deg. ATDC. Secondly, the inlet valves no longer open at 11.5deg. ATDC, but now open at 0.5deg. BTDC.

Thus, instead of intake air flow being checked for 2.5deg. between 9deg. and 11.5deg. ATDC, there is now substantial flow of air in the inlet tract, creating a considerable cross flow between inlet to exhaust.

This means Air flow inertia - resistance to flow - within the inlet tract has diminished by a considerable amount. Less inertia results in a better cylinder fill! (1)

To add to this, one must take into account, the inlet valves now open 0.5deg. BTDC, just before the start of the induction stroke - the time when the cylinder is now free to ingest inlet air and is is the full 180deg. from TDC to BDC.

Purely on extrapolation, this amounts to an increase in Volumetric Efficiency of { (180-11.5)/180 } = 9.361%. (2)

The combination of these two factors, scavenging and increased air flow over the full 180deg. induction stroke in themselves will contribute to increased specific power output.

These to elements should enhance the figures achieved with all other physical changes to the valve timing; increased duration, cat-less manifolds and Sports Cat, removal of the resonator and replacement with Supersprints Stainless Steel centre section, not to mention improved oil flow/pressure regulation, valve timing accuracy and shortening of VVT response time.

Given a Dynamometer run has yet to be done, I continue to speculate what the actual increase in power will be. However, the way the car is performing and my continual musing over what to expect, still leads me to believe it will be well over 300 bhp. I speculated 315 - 320 and I think it is not an unreasonable assumption.

I have only just got the car back after the clutch being repaired so I will take my time before I commit to booking a run.

All good at the moment however. But the Alfa boxes are restricting the engine little. Even with them fitted however, I think the power will be in that region.

 
« Last Edit: August 13, 2021, 03:51:06 PM by Ascari32 »

Ascari32

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #6 on: August 13, 2021, 05:50:31 PM »
Quote: -

"There is a remarkable similarity in shape between an engine's VE curve and its torque curve. For contemporary naturally-aspirated, two-valve-per-cylinder, pushrod-engine technology, a VE over 95% is excellent, and 100% is achievable, but quite difficult. Only the best of the best can reach 110%, and that is by means of extremely specialized development of the complex system comprised of the intake passages, combustion chambers, exhaust passages and valve system components. The practical limit for normally-aspirated engines, typically DOHC layout with four or more valves per cylinder, is about 115%, which can only be achieved under the most highly-developed conditions, with precise intake and exhaust passage tuning."

Ignoring all other considerations increasing Volumetric Efficiency will produce a pretty similar increase in engine torque.

My 159 engine before it failed was producing 266.2 BHP @ 6670 rpm.

Therefore, as torque response is very close to that of an engines V.E. response, an increase of 9.361% in volumetric efficiency, would extrapolate as a new max power figure of 266.2 x 0.9611 = 291.119 BHP.

This is not an absolute given figure as other factors come into the equation. However, like for like, these factors also affect the standard reference figure, so it is likely to be very close indeed.

This also goes some what to explain the reluctance of companies like Colombo Bariani to give expected power increases when using their cam shafts. I did however elicit details of expected torque increase. In this regard, they are on safe ground with their special camshafts for the 159, as they did indeed quote a nominal figure of 10% torque increase. Other details; although sketchy, remain in confidence.

If they increased valve lift, it would need to be substantial to overcome the inherent NVO of the 3.2 JTS valve timing, placing greater stress on valve springs, extra loading on camshafts and increasing the potential for valve/piston interference. Also, possibly the need for stronger springs to avoid "valve bounce", again placing extral load upon the cam lobes.

However, by increasing duration - as they have done, the load on the valve springs remains light, wear of the cam lobes is kept to a minimum and there is less likelihood of valve/piston interference. But they have overcome the inherent NVO and thus, substantially increased the V.E., which will almost correlate to a similar increase in torque!

My analogy has not been fully explained here as I would need to write a whole chapter, if not a book on my assertions.

However, it is based on the premise that, if all the modifications to my engine were in place, a comparison between the engine fitted with Alfa's standard cams and the C.B. cams would net a 9.361% increase in torque, with the C.B.'s fitted.

This I can confidently say, reflects the true cost of Alfa's choice of valve timing. All other considerations accepted! And it re-enforces my belief that the 3.2 JTS would be more powerful had the choice of inlet camshaft been one which produced Positive Valve Overlap.

I shall no longer consider refitting the exhaust camshaft or doing A/B comparisons as I am confident in both my rudimentary calculations and my assumptions wrt increased power levels.

I will however, pursue having the Alfa Inlet camshafts reground, maintaining the same lift, but increasing the duration from 254deg. to 278deg., or to whatever Colombo Bariani recommend.   

Ascari32

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #7 on: August 24, 2021, 08:20:09 PM »
Just don't seem to be able to close this project out - Oil and Filter changes are to be expected. However a clutch failure after less than ten thousand miles was not.

That was sorted by the garage after prevailing upon the spares company to bear the cost of parts and half the labour. But that knocked the steering out and resulted in a "Graunching" sound on the most modest of left or right lock when pulling away and the steering wheel was out of kilter. So back it went.

All done this morning however - four wheel alignment and steering wheel centred. Oil and filter done, so good to go for another few thousand miles. Steering now beautifully quiet from the off. And increasingly, the exhaust system seems to be quietening up ?????

Now I have to give some serious thought to getting her Dyno - tested, given the oil and filter have just been replaced. I wanted to put the Ascaris back on, but they won't be ready for another week. So do I bite the bullet and book a run with Clive Atthowe at Norwich? I need to have couple of days to think about it. But it is a question that needs answering.

« Last Edit: August 25, 2021, 05:21:52 AM by Ascari32 »

torquemeister

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Re: 3.2 Q4 modified - outstanding issues.
« Reply #8 on: August 30, 2021, 05:15:13 PM »
Hi A.T!

Is yours a Q4? I need to try something as I am told I will have to go to nineteens to accomodate bigger calipers/discs.

HI, if you are on 18" and want to fit the BBK (330mm should be standard on the 3.2 anyhow) then it fits no problems? I have the Prodrive 19" Brera S rims and the BBK just clears..........



If you are wanting better braking performance then I suggest that a retrofit of Tarox black pads and sprint? discs solves the "spongy feeling BBK as standard). I bought a brand new Q4 V6 Brera in Singapore and the brakes were less than impressive. So I upgraded to Tarox and problem solved.

When I moved here I bought another (SH) Brera and retrofitted the Tarox setup as I had in Singapore - let me assure you that they with decent tyres pull up on a dime when needed.

Current Fleet:
2010 Brera V6 AWD Auto - Singapore
2008 Brera V6 AWD Auto - Tasmania
Previously:
1978 Alfetta GTV 2.0L - Adelaide