Street wheel alignment settings

[RC924]

I`m in need of a 4 wheel alignment after recently refreshing & upgrading the suspension. Car is a 924 fitted with early 944 (steel arm) 5 lug suspension. Only street driven but rarely below the legal limit and often on twisty mountain roads.

Mods include:
All polyurethane bushes
250#F, 27mm TBs. lowered about 1" all round and leveled
tires 215/45/17 F, 255/40/17 R

Found lots of recommendations for track setups, particularly regarding camber, but no specific info for a street car. Of course I want it to handle the "best" on what is fitted while still retaining good tire wear and a neutral to slight understeer.

So should I just get it all set to the stock specs or what do the suspension gurus here suggest?

Thanks for any advice.

Stock settings:

[krystar]

as long as u keep toe 0, u shouldn't see any abnormal wear on the tires.

[962porsche]

porsche 944 service bulletin i have that was send out to the dealers back in 1985 states to tow in the front wheels to 1/16 inch . this is to stop steering wheel shake at speed . it was found that the 944 using VW control arms and rubber bushings tows the wheels out up to about 6MM when at speed . this also applys to the later aluminum control arms thow the arms maybe stronger the rubber that the bushings are made from is not . an alignment rack should have the stock 944 settings to do the car .

[chrenan]

I run a street/track compromise alignment. Zero toe, 4 degrees positive caster, -2.5 degrees of front camber and -1.4 degrees of rear camber. I have no rubber in my front end with blaszak control arms.

[John_AZ]

Originally Posted by 962porsche

porsche 944 service bulletin i have that was send out to the dealers back in 1985 states to tow in the front wheels to 1/16 inch . this is to stop steering wheel shake at speed . it was found that the 944 using VW control arms and rubber bushings tows the wheels out up to about 6MM when at speed . this also applys to the later aluminum control arms thow the arms maybe stronger the rubber that the bushings are made from is not . an alignment rack should have the stock 944 settings to do the car .

Thanks, good to know about how to avoid wheel shimmy/steering wheel shake.

John

[m73m95]

Originally Posted by 962porsche

porsche 944 service bulletin i have that was send out to the dealers back in 1985 states to tow in the front wheels to 1/16 inch . this is to stop steering wheel shake at speed . it was found that the 944 using VW control arms and rubber bushings tows the wheels out up to about 6MM when at speed . this also applys to the later aluminum control arms thow the arms maybe stronger the rubber that the bushings are made from is not . an alignment rack should have the stock 944 settings to do the car .

Not only does Porsche say this, but so do all car manufactures. You never want your toe at 0. Its unloads the suspension pieces, creates vibrations, and at highway speeds will actually toe your tires in a direction you don't want them to go.

Rear wheel drive cars usually want toe in

Front wheel drive cars usually want to out. With the front wheels pulling, they will have a tendency to want to toe themselves in.

[962porsche]

you tow in front drive cars becouse of the weight load on the front wheels in a turn . a front drive car will lift its inside rear wheel . becouse of this it forces the front out side wheel to want to turn in more . a rear drive car wants to lift its inside front wheel in a turn . all cars when going in a straight line want to tow the front wheels out and roll them selfs under the car . if you are using better bushings that rubber ones you then can set the front wheels with 0 tow as there should be no deflection in the bushings .

[chrenan]

Originally Posted by 962porsche

if you are using better bushings that rubber ones you then can set the front wheels with 0 tow as there should be no deflection in the bushings .

Exactly why I noted that I use blaszak control arms, they have teflon lined spherical bearings, so I run zero toe.

[RC924]

Thanks for the input guys.

Originally Posted by 962porsche

porsche 944 service bulletin i have that was send out to the dealers back in 1985 states to tow in the front wheels to 1/16 inch . this is to stop steering wheel shake at speed .

Interestingly, 1/16" toe in correlates to 0.15° or 0° 9' on a stock size tire diameter, so is spot on with Porsche`s published recommendations of 10' +/- 5'.

The center steel insert in the 30 year old rubber bushes that I removed was offset to one side from memory, would have to be towards the inside, so the advice given here and in the TSB sounds logical.

Originally Posted by chrenan

I run a street/track compromise alignment. Zero toe, 4 degrees positive caster, -2.5 degrees of front camber and -1.4 degrees of rear camber.

As my suspension knowledge is very limited, I ran those settings past the alignment tech today when I phoned for an appointment. His opinion was that is a track setting and far too aggressive for a street car compromise, and suggested no more than the outer tolerances from the specs. IDK. Maybe he is just covering his legal butt, although they do lots of 911`s and other track cars. Perhaps you mostly track your 951 and go on shorter drives? I know there are similar long distances in Canada as in Oz but still have bad memories of 2 scrubbed out tires (on a GM Commodore) after 1000 miles of straight driving across the Hay Plains. Attributed that to a stoned apprentice at Goodyear rather than the camber but still a bad experience. Appreciate your input though and only repeating what I was told.

Listening to the "expert`s" advice, he more or less confirmed what I read online at a few sites, including tirerack

If you are an assertive driver who enjoys driving hard through the corners and expressway ramps, a performance alignment is appropriate for your car. A performance alignment consists of using the vehicle manufacturer's range of alignment specifications to maximize the tires' performance. A performance alignment calls for the manufacturer's maximum negative camber, maximum positive caster, and preferred toe settings. While remaining within the vehicle manufacturer's recommendations, these alignment settings will maximize tire performance.

One more question:
Is there any caster adjustment on our cars or is it just what you get? With stock fixed 944 upper strut mounts and no other mods or kit that is.

[matty89]

On the caster block at the rear of ur lower control arm

Thanks for the input guys.

Quote de 962porsche

porsche 944 service bulletin i have that was send out to the dealers back in 1985 states to tow in the front wheels to 1/16 inch . this is to stop steering wheel shake at speed .

Interestingly, 1/16" toe in correlates to 0.15° or 0° 9' on a stock size tire diameter, so is spot on with Porsche`s published recommendations of 10' +/- 5'.



The center steel insert in the 30 year old rubber bushes that I removed was offset to one side from memory, would have to be towards the inside, so the advice given here and in the TSB sounds logical.

Quote de chrenan

I run a street/track compromise alignment. Zero toe, 4 degrees positive caster, -2.5 degrees of front camber and -1.4 degrees of rear camber.

As my suspension knowledge is very limited, I ran those settings past the alignment tech today when I phoned for an appointment. His opinion was that is a track setting and far too aggressive for a street car compromise, and suggested no more than the outer tolerances from the specs. IDK. Maybe he is just covering his legal butt, although they do lots of 911`s and other track cars. Perhaps you mostly track your 951 and go on shorter drives? I know there are similar long distances in Canada as in Oz but still have bad memories of 2 scrubbed out tires (on a GM Commodore) after 1000 miles of straight driving across the Hay Plains. Attributed that to a stoned apprentice at Goodyear rather than the camber but still a bad experience. Appreciate your input though and only repeating what I was told.



Listening to the "expert`s" advice, he more or less confirmed what I read online at a few sites, including tirerack

Quote

If you are an assertive driver who enjoys driving hard through the corners and expressway ramps, a performance alignment is appropriate for your car. A performance alignment consists of using the vehicle manufacturer's range of alignment specifications to maximize the tires' performance. A performance alignment calls for the manufacturer's maximum negative camber, maximum positive caster, and preferred toe settings. While remaining within the vehicle manufacturer's recommendations, these alignment settings will maximize tire performance.

One more question:

Is there any caster adjustment on our cars or is it just what you get? With stock fixed 944 upper strut mounts and no other mods or kit that is.