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Old 06-28-2010, 12:15 PM   #1
bigjae1976
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Suggestions on Alignment/Suspension Setup

I've been running OEM 17s (225fr/245rr) with the following alignment specs:

Front (L/R)
Camber 2.25/2.21 deg
Caster 7.07/7.01 deg
Toe 1.5/1.5 mm

Rear (L/R)
Camber 2.77/2.78 deg
Toe 2.5/2.3 mm

Cross weight is 50.1%
UUC Sways are mid stiff in the front, full soft in the rear

There is a definite lack in front end grip.

Planning on going running my 17" ARC8s (255 square). I know I need more front camber.

I was planning on trying to get 3 degrees of camber in the front with my Vorshlag camber plates. Is that enough?

How much toe should I run in the front?

How much will the 255s up front help?
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Old 06-28-2010, 12:41 PM   #2
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Quote:
Originally Posted by bigjae1976 View Post
I've been running OEM 17s (225fr/245rr) with the following alignment specs:

Front (L/R)
Camber 2.25/2.21 deg
Caster 7.07/7.01 deg
Toe 1.5/1.5 mm

Rear (L/R)
Camber 2.77/2.78 deg
Toe 2.5/2.3 mm

Cross weight is 50.1%
UUC Sways are mid stiff in the front, full soft in the rear

There is a definite lack in front end grip.

Planning on going running my 17" ARC8s (255 square). I know I need more front camber.

I was planning on trying to get 3 degrees of camber in the front with my Vorshlag camber plates. Is that enough?

How much toe should I run in the front?

How much will the 255s up front help?

Are you on coilovers? Shoot me your email and I can forward you the chassis setup sheet I have for the e36. I would start there and then fine tune it.
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Old 06-28-2010, 01:15 PM   #3
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PM sent...thanks!
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Old 06-28-2010, 01:43 PM   #4
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Of course this will all depend on how much roll resistance you have front & rear, so you may need to make some spring/bar changes to tune for the right over/understeer that you want, but a good start for alignment settings probably won't change a ton.

For the front, dial in as much camber as you can get. I'm at -3.4 on one side, -3.7 on the other, and I can't get any more, so that's what I use. You likely won't be able to dial in more caster. I've found 1/8" of toe out really helps turn-in response, but it's a bit darty on the street, and can be rough on tires if daily driving, so 1/16" toe out is a good compromise.

For the rear, I'm running -2.5 deg of camber, and 1/4" of toe in. Pretty standard BMW settings.

In general, especially without an LSD, I've found that the less rear bar the better. (I'm running without it)

Pay attention to how much roll you're getting up front. If you're getting into the bumpstops, adding more spring or bar there will help with front grip. I found moving from 550 lb springs and the H&R 27mm bar on soft to 650 lb springs and the bar on stiff helped. I recently moved to the 30mm bar, and full stiff on that I think was too much.
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Old 06-29-2010, 02:12 AM   #5
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I should also mention that I start with 38psi cold pressure in all 4 tires. I chalked (actually used whiteout) the tires and I am definitely wearing away the top of the little arrows on the sidewall. Hot PSI was ~46, max rated PSI on the tires is 51.

I'll try to snap a pic later.

Quote:
Originally Posted by murph1379 View Post
Of course this will all depend on how much roll resistance you have front & rear, so you may need to make some spring/bar changes to tune for the right over/understeer that you want, but a good start for alignment settings probably won't change a ton.

For the front, dial in as much camber as you can get. I'm at -3.4 on one side, -3.7 on the other, and I can't get any more, so that's what I use. You likely won't be able to dial in more caster. I've found 1/8" of toe out really helps turn-in response, but it's a bit darty on the street, and can be rough on tires if daily driving, so 1/16" toe out is a good compromise.

For the rear, I'm running -2.5 deg of camber, and 1/4" of toe in. Pretty standard BMW settings.

In general, especially without an LSD, I've found that the less rear bar the better. (I'm running without it)

Pay attention to how much roll you're getting up front. If you're getting into the bumpstops, adding more spring or bar there will help with front grip. I found moving from 550 lb springs and the H&R 27mm bar on soft to 650 lb springs and the bar on stiff helped. I recently moved to the 30mm bar, and full stiff on that I think was too much.
Since it really softens the rear end when have no rear bar, would that only make sense for stiffer springs? I think the PSS come with progressive springs and are fairly soft compared to most coilovers. I do understand the reasoning because I did have my rear bar on full stiff for my first track day with the LSD. The rear end felt quite lively...the LSD really changed the character of the car on the corner exit, in a good way.

I think part of the issue is the twinscrew compressor and manifold are quite heavy which makes the car a little more nose heavy. I think I may have to go full stiff in the front as well.

I should just upgrade to the ASTs...

Last edited by bigjae1976; 06-29-2010 at 02:18 AM.
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Old 06-29-2010, 07:08 AM   #6
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In my testing (not based on measurement) I estimated that the H&R rear bar on full stiff is roughly worth about 175 lbs of roll resistance. I could be off on that, it's just the result of yanking it and replacing with spring until it felt the same. I'm sure the stock bar would be less.

Yes, proper linear rate springs and adjustable shocks to match them will help this process, and the ASTs are great, with the PSS9s you may want to keep that rear bar in there. I believe those shocks control rebound, which you'll want to set fairly low to keep that inside tire on the ground.

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Old 06-30-2010, 03:44 AM   #7
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I have PSS...so no damping adjustment.

While I am on the subject of the ASTs. Are the 4200s really worth it for a street/HPDE car? I don't need to set lap records or anything, just wanna drive on the track for fun. I'm not sure that I need a double adjustable shock. Heck, I'm doing OK with a non-adjustable shock and really haven't thought twice about getting the PSS9s.

But, I would hate to get the 4100s and then say, "Gee, I really should have gotten the 4200s".
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Old 06-30-2010, 08:12 AM   #8
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Being able to adjust compression is really nice for a car with no LSD, but if it's non competitive hpde I'd say you're probably fine with the PSS dampers, but you may want to consider some linear springs to change until you have the car balance where you want it.
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Old 07-02-2010, 07:51 PM   #9
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Thanks for the advice!
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