Alfa 911

Started by GTVeloce, December 09, 2011, 11:33:12 AM

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Graham Stafford

Just came across your thread - nice car, nice philosophy...  Just one thing:  911 is an upside-down 116!  Do be careful out there!

GTVeloce

Ha ha! Well spotted Graham. Yes, hopefully that's not the fate of my resto!

Quick update: I have mostly finished my tidy up of the engine and it is now installed along with the driveshaft. I just need to finish curing the cam cover (painted it wrinkle finish black) and bolt on. Then I will take a few photos and post them.

One snag I have come across: I am using the isostatic linkages and in doing so I need to remove some metal to allow room for the linkages. I did this before in another car without any problems. On the weekend I have done the same thing but this time the linkages are coming in contact with the tunnel as well. I'm comfortable removing a little metal that is not structural but the tunnel I don't wish to touch. What I don't understand is why this is being a problem this time! The bodies are both from 83 116 GTV's so they should be the same. The transaxle crossmember went in without any problems so I don't think that is any issue. Any thoughts?

aggie57

When you say coming into contact with the tunnel do you mean around the isostatic mechanism itself, right in front of the clutch housing?

The floor pan on isostatic cars is different to non-isostatic ones; the change was made around september 1984 so a 1983 car will have the earlier floorpan.  Isostatic cars have a depression in the floor at the point to provide the necessary clearance; pre-iso cars do not.

One commonly used approach for the above issue is to "relieve" the floor with a 4lb sledge.  Sounds rough but doesn't need much and no metal needs to be removed.
Alister
14 Alfa's since 1977. 
Currently 1973 GTV 2000, 2020 911 C2S MT, 2021 Mercedes GLE350, 2023 Polestar 2 LRDM
Gone......far too many to list

GTVeloce

I have finally had a chance to get around to putting pictures of the engine in. I also have started playing around with putting the body bits and pieces back on. Just testing their fitment at the moment and then will paint them before fitting them properly. What are people's thoughts on colour of bumper etc? I am leaning towards body colour but some have suggested metallic grey would be better. I have painted window surrounds and small trim pieces in metallic grey.

Sorry Aggie57, I just realised I hadn't responded to your comment. My 83 body is pre-isostatic but so was the previous one. With the previous one all I had to do was 'relieve' some of the metal to make space. This time I have done that but the linkages are still rubbing quite severely on the tunnel. I am wondering whether maybe I have put the linkages on incorrectly this time. It looks ok but clearly something doesn't match up.

julianB

Julian- I f**kn love it  ;)

Another Julian with the same philosophy on a GTV6!

Mine's an 85, was a 2.0, engine now a 2.5 V6 - 11.3:1 comp, big valves, Ex Colin Bond camshafts and an ancient Haltech F7 or something. (You may have seen it years ago in a silver Alfetta sedan, which is now a 3.0 12v TT). Revs to 8000, 180rwhp.

Box is 75 3.0 with a 4.3:1, re-packed LSD, Iso linkage and a custom clutch, fitted TS front brakes and currently on Bilsteins with lowered and stiffer rear springs.

Work to be done:

Mine's a little more serious on the resto side of things than yours looks to be- copped a hit up the rear beaver which I un-picked- it'll have a repair section welded in and some rust cut out. All glass and framing out, all trim off= to be painted like yours- red with gunmetal trim. Full (original) Zender kit to be fitted.

* Floors have had ALL bitumen chipped out and are being painted with www.lizardskin.com
* Original Tan pinstripe material  (apparently on its' way from Israel....) purchased to re-trim the interior back to factory. Got the Recaro LXs in the picture. Old seats are not worth selling- they aren't original GTV mesh headrest ones, but older Recaros- they're gone.
* Keeping wind up windows, and taking a different path to you, as I want to keep it around the 1050- 1100kg mark with the V6 in it.
* Stereo to be made up in a portable box so I can remove it for the track. Hard to imagine, but this will happen down the track.
* Swapping to 5 bolt hubs and fitting 156 Superturismo rims for now. These will become my track rims when the road rubber wears out.
After I get it registered again,
* RS Racing Coilovers
* GTA brembos for the front, trying to figure out vented rears on a budget.
* Haltech E11V2 to be wired in
* GSXr 1000 Throttle bodies - I have a mate who'll make up a manifold for me- he's a tool maker- builds his own EVERYTHING.

After it's painted, I'll be putting it back together.
I'm about to move for a few months for work, so when I get back, I hope to have some photos to show!

PS- Get yourself a good aftermarket ECU and start saving for a turbo for that TS.
On stock compression, a Nissan SR20 GT28 will put 10-12 psi through a good air to air intercooler on that thing and you won't know what to do with yourself!
85 GTV6 "Juliet"
GTA conversion-
AHM ITB setup, Jim K manifolds & 10.3 cams, M84
17" Work Meister S1R
330mm Brembo front, vented rears
RS coilovers and bits
Recaro LX mesh headrest buckets

'68 step nose Junior "Romeo"
bare metal project

GTVeloce

Well, things have been progressing, just slowly. I have managed to source a replacement for my Frankenstein like upper radiator hose. The lower radiator hose from a Jeep Cherokee 1994 (Gates 05-0905) fits very well. I lopped a little off both ends but otherwise it just slips on. It even comes with a metal coil through the centre to protect against kinks. This is designed for anyone who fits a standard TS engine into a GTV with the standard radiator.

festy

Quote from: julianB on April 11, 2012, 08:49:09 PM
PS- Get yourself a good aftermarket ECU
The factory TS ECU is pretty flexible - unless you're planning something wild you shouldn't need to go aftermarket...

Tristan Atkins

Hi GTVeloce,

You conversion looks like its coming along quite nicely. I just wanted to give you the heads up regarding the clutch master cylinder.  If you use the original 116 pedal box the clutch master cylinder will fowl upon the intake.  To prevent this the Alfa 75 pedal box has a modified clutch master mount that angles the cylinder underneath.

If you get stuck anywhere along the way please send me a message and I'll do my best to help out.

Kind regards,

Tristan

GTVeloce

Tristan - thanks for the heads up regarding the clutch master cylinder. I discovered that the hard way the first time installed a TS engine into a GTV. Didn't make the same mistake this time... And thanks for the offer of help - I may very well take you up on that offer soon!

Festy - I'm not planning on doing anything to the engine at this stage. I do plan to take it to the track but have put my money and effort into suspension improvements rather than engine. Also, in keeping with the design philosophy for the car, it has to be able to comfortably run A/C on a hot day without any issues at all which is easy while the engine is stock. That said, the internals were rebuilt about 15k ago plus I have cleaned up all the peripherals this time around so the engine should still give about 110-115 hp at the rears which is enough to enjoy.

Duk

#24
This thread has me rather intrigued. The philosophy is a good 1, but I'm curious about the approach.
I figured it may be worth adding a few comments, take them or leave them as you will.

Really good road cars and really good track cars have a very rigid chassis. Track cars obviously achieve this with a comprehensively integrated roll cage. The forces and loads are much higher in a dedicated track car (read: slick tyres which require much higher spring rates to get the best from them) and so are the chassis rigidity requirements.
In standard form, the transaxle chassis doesn't have a good reputation for chassis rigidity, especially at the front, which is also the worst performing suspension (can you say 'understeer'?).
The stiffer your front springs, bump valving in your dampers and anti roll bar, the more the chassis will flex. Please be aware that stiffer (thicker) torsion bars will flex the front of the chassis more, regardless of what some may say! If the wheel is less inclined to move up because a big fat torsion bar is stopping it, that vertical force will be transferred into the chassis. The same said for fat anti roll bars.

Spring rates, damper valving and front suspension geometry.
A tyre can only develop its maximum available grip levels when the tread is in perfect, even contact with the road.
The Alfa's front suspension has a very poor camber curve with bump travel!
The 'die hards' will hate this! The Alfa's front suspension is so bad in its basic dimensions that it quickly gets to a point and actually starts to gain positive camber with bump travel! The more you lower the standard geometry suspension, the closer you are to that point when it starts to gain positive camber.
This is a direct result of having the 'suspension virtual swing arm's pivot point' on the wrong side (the outside) of the wheel. Add to this gain in positive camber with bump travel, the positive camber that is gained with body roll and you end up with an outside front tyre (the hardest working tyre) that has a very poor tread contact with the road and so very little grip!
The other byproduct of this poor front suspension geometry is a low roll centre height. The Alfa's front suspension geometry all ready starts with a low roll centre height, but it also causes the roll centre height to go down faster/further than any lowering that is done. This causes a lot of body roll for a given spring (torsion bar)/damper/anti roll bar combination. If you took a standard TB and anti roll bar TA chassis Alfa and lowered it, it now suffers from MORE BODY ROLL!!!

By correcting the geometry of the front suspension you can fix 2 problems at once. By raising the top ball joint or lowering the bottom ball joint, the virtual swing arm's pivot point is moved to the correct side of the wheel, the inside. This gives a much better camber curve with bump travel and also brings the roll centre height up.
So now you have less body roll for your given spring(TB)/damper/anti roll bar combination and for the body roll that does happen, the tyre maintains a much better contact patch with the road. All of this is done without reducing the independence of the (independent) front suspension by using a huge front anti roll bar.

My personal approach to fixing the front geometry was to use Pace Engineering's long shank top ball joints. These cause a noticable amount of bump steer (toe in with bump) and the easiest and most effective fix I found, was to use a much more positive caster angle. About 7* instead of the factory spec 3*. More positive caster pushes the outer tie rod end down and this helps to reduce the bump steer. It also gives more negative camber with turn in, better self centering of the steering and better directional stability. The downside is more steering weight.

The TA Alfa's are still too softly sprung. It's not as much of an issue with the lighter 4 cylinder cars, but they can definitely benefit from more front spring rate. I haven't had the need to research front springs for the 4 cylinder cars (I have a V6 75), but I would seriously look at the wheel rates that 27.3mm torsion bars provide (191lb/in wheel rate).

Dampers (shock absorbers).
Well designed and well valved dampers will give good initial bump travel (low speed) damping but then gain no more damping force with with any further increase in damper speed (bigger bumps). This will allow the car to feel agile in initial changes in direction (turn in = low speed valving), but also negotiate bumps in the road surface(high speed valving) with minimal effect on the chassis.
This allows the car to negotiate bumps with the tyre firmly stuck to the road and still feel agile, responsive and well planted.

The only dampers that can achieve this kind of result are digressive valved dampers.

A basic linear damper is a force versus (damper)velocity device.
The faster you move it, the more it resists that movement!
The faster you move the damper, the greater the pressure build up inside the damper as more of the damper's oil is trying to flow through the valve(s) in less time.
Digressive valve dampers use internal pressure relief valves to prevent the damper's internal pressure from building up too high and causing an increase in damper force, as the damper's speed increases.
The obvious name to drop, for anyone who has done any sort of research, is Bilstien!
Koni Yellow are a linear valve damper and have too little initial(low speed) bump valving to help the car feel agile during turn in, but gain too much bump force when the wheel negotiates an actual bump. Add higher spring rates and the linear valve damper characteristics are exacerbated.
Koni Yellow's are NOT adjustable for bump valving n standard form. They can be revalved, but will still be a linear valved damper.

By doing things like increasing the chassis torsional rigidity, correcting the front suspension geometry, adding a reasonable amount of spring rate (especially to the front) and matching this with well specified, digressive valved dampers, you should be able to achieve an excellent performing road car car that can negotiate bumpy road surfaces with both agility and 'sure footedness' and still hold its own quite well on a track.
Your other option is to turn it into a crashy, banging POS that hates anything but low amplitude bumps and uses silly amount (for a road car) of negative camber to try and get some respectable levels of grip from the front tyres.
Or you could have a chassis stressing/flexing thing that cranks massive spring rates, huge anti roll bar rates, but with some decent designed dampers, to try and stop it from hammering the poor ol' thing to death, again to try and get some decent levels of grip and handling characteristics............

GTVeloce

Thanks Duk. That was quite comprehensive! I am not a whiz at all the principals at play but thanks to brother (who is the engineering whiz) I have a workable understanding and agree mostly with your comments. To try and accomplish my goals I have spent time and effort into the suspension as best I can and I have tried to rectify as many of the handing problems you mention. Therefore;
- I have no welding gear nor experience so have held off doing any chassis improvements but I do have a few plans for the future. After having driven my brothers Porsche you really do appreciate the extra chassis stiffness! My plans include a custom made internally mounted roll bar that is going to be mounted underneath my sound system. Basically it will look just like a standard half cage only not as high. Obviously it won't be as useful and it won't provide roll-over protection but it should provide some extra rigidity as well as provide a mounting location for my sound system rather than having it effectively just sitting in place. The sound system was mounted in this location for a number of reasons but not least of which is keeping the weight low and centered.
- I am also going to experiment with some bars a la the 75 that bolt along the car between the TA and just behind the TB. I'm not as confident as to how effective this will be especially as in my car the TB's are not directly mounted to the chassis but into a cross bar. Still, it's a fairly easy mod to try.
- I would love engine bay chassis stiffening as you have done in your 75 but that requires skill beyond me.

As to the actual layout of the suspension, I have tried actually used a number of the things you mention, namely;
- I have used Pace's long shank upper ball joints
- I will be experimenting with caster angle once the car is drivable again
- I have upgraded to 28mm TB's (again Pace) to improve the suspension stiffness
- I am using Bilstein's all round and have found them to be excellent in the past
- I am going to be experimenting with Camber once it is driving again but previously I had 3 deg and surprisingly found it very good. I even had consistent tyre wear but I'm not sure if that was a combination of driving style and/or original TB's. Most likely the new set-up will employ somewhere between 1-2 deg.
- I have stiffer rear springs but not outrageous levels of stiffness.

I would love to improve the rear angles via a bent de dion but I couldn't justify the expense at this stage. I also have changed all suspension rubbers using a mixture of rubber and PU. Basically if I think PU will provide too much harshness I have opted for rubber e.g. the upper A arms to body have remained rubber but A/R bars and Watts linkage is now all PU. I am going to experiment with a mixture of rubber and PU for the caster arms to see if I can get a good compromise between losing steering angles and crashiness.

I have experienced both gamuts of Alfa suspension, from the sweet handling to the, as you say, crashy POS and hope that my mods will be towards the latter. Time will tell.

On a different but related note: I experimented with tightening the Koni reds in the rear of my mostly stock 75 and it feels disastrous! I will be turning them back down first chance I get. Tightening the Koni yellows in the front and it made an improvement but they still don't feel as good as the Bilsteins.

GTVeloce

QuoteI have experienced both gamuts of Alfa suspension, from the sweet handling to the, as you say, crashy POS and hope that my mods will be towards the latter.
Ahem, make that the former...

Duk

GTVeloce, it reads like you have a very good handle on making a very good road car handle even better.
Indeed, the set up you plan to use for your GTV sounds like a very, very capable 1!
If you were able to find a way to strengthen the chassis at the front of your Alfa, I do genuinely believe that it will reap rewards for you.

I really do believe that adding a series of small improvements in many areas of the car will make it better on the whole. So rather than expecting 1, or even 2 or 3 or 4 changes, a series of relatively small changes will achieve a very large improvements that could be considered more inline with what a car manufacturer would do rather than what some clown in his shed my throw together.

Keen to read more about your work.

Fylnn

Not trying to wade into someone elses thread here.  But followed this with interest.  But I have the opposite issue in that I have raised the front of my GTV6 to use for gravel rally.  As such my lower control arm is sitting at or just above horizontal, and i am considering raising it another 20mm after the last rally experience.  (Did anyone say alloy sump)  Fortunately it has a good sump guard that took on the rocks (bolders) and won.

I intend to take all this knowledge and spend some quality time lying under the front end this weekend to understand about it.  The car has a welded in roll cage, all the way to the front towers and is running 28mm TB's.  But I am wondering if the long shank ball joints would benefit me in the same way as a lowered car.  Geometery being what it is I am thinking maybe it would help in keeping the camber at the front near optimum through the suspenison travel?  That would help with it get some better bite and better turn in.  Then I can go sort my other issue in that the back end wants to step out especially when the road goes off camber. 

GTVeloce

I have a standard 75 TS that I think has been lowered slightly at the front and I am also going to raise that to try and improve the ride quality as well improve ground clearance. This car is going to see some pretty rough roads soon! So, please let me know how you go with your efforts.

Also, I came across this table a while ago which is a good resource for seeing the different ways to fine tune your suspension to correct any imbalance.

                               For More Understeer      For More Oversteer
Front Tire Pressure       Lower                             Higher
Rear Tire Pressure       Higher                             Lower
Front Tire Section       Smaller                             Larger
Rear Tire Section               Larger                             Smaller
Front Wheel Camber       More Positive                     More Negative
Rear Wheel Camber       More Negative                     More Positive
Front Springs               Stiffer                             Softer
Rear Springs               Softer                             Stiffer
Front Anti-Roll Bar       Thicker                             Thinner
Rear Anti-Roll Bar               Thinner                             Thicker
Front Roll Center               Higher                             Lower
Rear Roll Center               Lower                             Higher
Weight Distribution       More Forward                     More Rearward