944s2 Alignment car darts, nervous

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I am having a problem in which driving at highway speeds the car wants to dart to the left or right and I have also heard the term “nervous” being used which I think applies to my situation. The car is a 1989 944s2 and I spent 6 years doing a total restoration on it and making performance or reliability upgrades as warranted. The car has been in the alignment shop several times in hopes that the issue will be resolved, but it still remains.

Apparently TSB 49303 explains that going from a 16” wheel to a 17” wheel requires a different caster setting. However, I am running 18” wheels and is commonly done on the late 944’s.

What I am hoping for is someone who can analyze my latest alignment report or if someone can spot an obvious problem with the configuration. The shop that has been doing the alignments on this car are the only shop in town that specializes in high end European cars. I feel that the problem resides within the alignment settings since every moving part the front end is brand new and I will list the parts below to help with the analysis.

Wheels: SSR GT10, Front 18x9, Rear 18x10
Racers edge camber plates, mono-ball
Elephant racing “sport” caster blocks
Rebuilt steering gear with about 100k miles on the pinion gear
New steering shaft and u-joints
Racers edge billet A-arms
New tie-rods
Koni inserts with adjustable height

Thanks in advance
Page in Bend Oregon




Sent from my iPad

[walfreyydo]

First question: do you have any play or looseness in the steering at highway speeds?

Also, front right has substantially more caster than the front left. Caster is something that is adjustable on these cars and I wonder if the alignment shop realized this? They should be the same left and right.

Low profile tires can also affect how the car tracks causing it to want to follow grooves in the road.

[RedCarGuy]

Agree on the caster, I don't know why it would be different left and right.

I also notice they changed the toe to positive (out) and you want the opposite for stability at highway speeds. I would have them toe it in similar to the "before" numbers.

[Pagebend]

Originally Posted by walfreyydo

First question: do you have any play or looseness in the steering at highway speeds?

Also, front right has substantially more caster than the front left. Caster is something that is adjustable on these cars and I wonder if the alignment shop realized this? They should be the same left and right.

Low profile tires can also affect how the car tracks causing it to want to follow grooves in the road.

Thanks for your input! The steering is a tight as I will get it and every moving part has been either replaced and or upgraded within the front steering and suspension system. I have a suspicion that since I am running an 18” wheel the problem resides in that caster setting but I am not an expert on setting up the alignment on these cars...I am going to look at the other alignment reports that I have had on this car and see if they show the same caster settings being different like the latest report I posted dictates.

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Supposedly they aligned it to the factory specifications but I am not certain since I do not know what the factory alignment specs are supposed to be. Not to mention that a tech bulletin TSB 49303 explains that going from a 16 to 17 inch wheel requires a different caster setting. I am not certain that this sort of compensation what made to allow for the larger wheel. I even took the TSB with me and showed it to the alignment shop.

[Pagebend]

Originally Posted by RedCarGuy

Agree on the caster, I don't know why it would be different left and right.

I also notice they changed the toe to positive (out) and you want the opposite for stability at highway speeds. I would have them toe it in similar to the "before" numbers.

Supposedly they aligned it to the factory specifications but I am not certain since I do not know what the factory alignment specs are supposed to be. Not to mention that a tech bulletin TSB 49303 explains that going from a 16 to 17 inch wheel requires a different caster setting. I am not certain that this sort of compensation what made to allow for the larger wheel. I even took the TSB with me and showed it to the alignment shop.

[Rasta Monsta]

Those specs are "sus-specs."

Take them this, and let them know the car is wandering:

[walfreyydo]

Also let them know that caster is adjustable on the lower control arm "caster" block...rear mounting point on the control arm.

Side note: lots of alignment shops do the "toe and go" thing with alignments, where they dont really look find tuning settings besides toe (since toe is what mostly wears tires). Be watchful for this.

[Pagebend]

Originally Posted by walfreyydo

Also let them know that caster is adjustable on the lower control arm "caster" block...rear mounting point on the control arm.

Side note: lots of alignment shops do the "toe and go" thing with alignments, where they dont really look find tuning settings besides toe (since toe is what mostly wears tires). Be watchful for this.

Your are correct and this is what I am afraid of. I really need someone that knows what they are doing as far as the alignment on this car... I am not confident in this shops ability but they are the only game in town. I am going to talk with them about the last report they provided and I really appreciate everyone’s input from this community. I have had to resort to this community’s input multiple time to solve problems.

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Originally Posted by Rasta Monsta

Those specs are "sus-specs."

Take them this, and let them know the car is wandering:

Thank you very much for this and I will print this and take to the alignment shop to compare it with the report they provided.. Another question is that since my car is an 1989 should I have it aligned to the 1989 or 1990 specs that you provided? Why the change in the camber settings from 89mod to 90mod. They are the same car and I am not aware of any suspension changes between those years...Does the camber change from 89 to 90 have anything to do with wheels size?

[Stoneguy]

Page,
I just did basically the same as you on my 86. I replaced everything on the suspension.
When I got it lined up at an indy shop, It just never came out right. I don't know if they use generic specs or what.. I too have 18x9 front and 18x10 rear and am running Michelin Pilot sport 4s tires. I finally "bit the bullet" and went to my Porsche dealer. They had the car for a day and a half but all I know is, the car tracks straight and doesn't wander at all. These are touchy little vehicles. When I get a minute, I will see if I can find the alignment sheet for this service and post it. (If I still have it)

[Pagebend]

Originally Posted by Stoneguy

Page,
I just did basically the same as you on my 86. I replaced everything on the suspension.
When I got it lined up at an indy shop, It just never came out right. I don't know if they use generic specs or what.. I too have 18x9 front and 18x10 rear and am running Michelin Pilot sport 4s tires. I finally "bit the bullet" and went to my Porsche dealer. They had the car for a day and a half but all I know is, the car tracks straight and doesn't wander at all. These are touchy little vehicles. When I get a minute, I will see if I can find the alignment sheet for this service and post it. (If I still have it)

You are a great American! I was hoping to speak with someone like you who knows exactly what I am faced with. Please post your specs and I am going to likely copy them. My car is only lowered about 3/4 than stock. How about yours?

[azbanks]

Where are you located?

I had one inde shop set the alignment on my 86 turbo and then my 90 S2 Cab and they were never quite right.
I took the 90 Cab to a different inde shop and they got it spot on. They were a longer drive and more money but they were worth it.

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Originally Posted by azbanks

Where are you located?

I had one inde shop set the alignment on my 86 turbo and then my 90 S2 Cab and they were never quite right.
I took the 90 Cab to a different inde shop and they got it spot on. They were a longer drive and more money but they were worth it.

I am in Bend Oregon. We do have a Porsche dealer here and I am likely going to visit them next week to discuss my issue. I understand that running 18”s with amplify any problems that I am having but many other with 18’s have successfully configured their cars. Every moving part is brand new and or an upgraded improvement on the steering and suspension system. I need someone with a Turbo or S2 with 18’s to post a copy of their alignment configuration and I will likely try to mimic it.

[dsfnctn]

It looks like you spent a bunch of money to make the car handle well.
I would recomend bringing the car up to Fordahl motorsports in Bellevue for the day and have Greg Fordahl at Fordahl Motorsports align the car for you. He is a 944 specialist. He has been a race engineer for at least 30 years.


https://www.youtube.com/watch?v=8__cHhtdjGM

[azbanks]

I run 18's from a 2002 911 Turbo on my car.
I am not sure what i did with the alignment sheet from the last shop that did mine. I'll see if I can find it.

[Stoneguy]

Pagebend,
I found it! Here you go.
Disregard the before readings. They were way way off because this was right after I did a complete front and rear suspension rebuild. Everything was removed from car and reinstalled. Hence the crazy values.

Also, My car is 1" lowered and I'm running the following:
Rear 18x10 ET47+7mm spacer Michelin Pilot Sport 4 S 275/35 ZR18
Front 18x8 ET50 + 7mm spacer Michelin Pilot Sport 4 S 225/40 ZR18

Ground Control coil over Koni to supplement stock torsion bars in rear
Koni adjustable inserts with stock coils in the front

Hope all this helps with your setup

[Pagebend]

Thank you STONEGUY. I have already been studying the data from your report and I am going to discuss it with the alignment tech at the dealership. I don’t think I want to go back to the same place after 3 unsuccessful alignments already. I really appreciate your help and this forum has always helped me make insightful decisions.