Subframe Camber Adjustments

[6SPD]

What up Rev!

A few months ago I pulled my subframe to swap in full poly bushings and a 3.46 and upgraded brakes. Now I'm looking at finally getting my car off of Mtech springs and Billys with either a GC set up or KW V1s.

How necessary are rear subframe camber and toe adjustments for lowering the car. I'm not looking to stance the car out by any means so to say. I'm looking to lower the center of gravity while still retaining the maximum contact patch that's possible.

Really just looking for subframe modification insight and what adjustments need to be made.

Thanks,

D

[FLG]

You can grab a set of raised bushings from Condor which will help camber without you having to spend money installing the adjustments. Judging by your post, im guessing you dont track your car..generally you will be fine with just the raised subframe bushings. Its not camber that really kills tires, its toe.

[6SPD]

You can grab a set of raised bushings from Condor which will help camber without you having to spend money installing the adjustments. Judging by your post, im guessing you dont track your car..generally you will be fine with just the raised subframe bushings. Its not camber that really kills tires, its toe.

I'm in the process of building an aggressive street car that will see road rallies, canyons, and the occasional track day, but not a full track build as you can probably tell because the bushings are poly opposed to solid.

[jlevie]

For the best handling you want 3-3.5deg or rear camber and a bit of toe in. But that will result in increased tire wear. Your choice as to which is more important.

[6SPD]

For the best handling you want 3-3.5deg or rear camber and a bit of toe in. But that will result in increased tire wear. Your choice as to which is more important.

Thanks for the insight! Do you happen to know the correlation between the inches of drop and the increase in camber? I'm already running offsets in the front that are adding some tire wear.

[Madhatter]

Whoever told you to run 3.5 degrees rear camber doesn't know how to setup a car. Especially since that a static measurement and would increase under compression.

Thats the sort of front camber measurement you might see on a race car, but not on the rear. The way to do it properly is to see how the tyre responds to temps, and alter camber to suit. But for everyone else, start at returning it to stock (which is about 2 degrees), or less than stock. You simply don't need that much rear camber on a car, should only really want to be adding camber if you are trying to correct wild oversteer. Also should be noted you should corner weight the car if running coilovers before getting this involved in setup. Likewise, wider rubber requires less static camber too.

If you want the best handling car, one that responds to slightest steering inputs, you want to run as much caster and camber as possible on the fronts, the a little bit of toe out (1-2mm). Rear as close as you can get to stock (or 1.5 degrees) camber a side with half a mm toe in. Twitchy in a straight line and will want to follow a lot of lines/ruts/cracks on the road, but it will turn in better than anything you have driven before.

[FLG]

Whoever told you to run 3.5 degrees rear camber doesn't know how to setup a car. Especially since that a static measurement and would increase under compression.

Thats the sort of front camber measurement you might see on a race car, but not on the rear. The way to do it properly is to see how the tyre responds to temps, and alter camber to suit. But for everyone else, start at returning it to stock (which is about 2 degrees), or less than stock. You simply don't need that much rear camber on a car, should only really want to be adding camber if you are trying to correct wild oversteer. Also should be noted you should corner weight the car if running coilovers before getting this involved in setup. Likewise, wider rubber requires less static camber too.

If you want the best handling car, one that responds to slightest steering inputs, you want to run as much caster and camber as possible on the fronts, the a little bit of toe out (1-2mm). Rear as close as you can get to stock (or 1.5 degrees) camber a side with half a mm toe in. Twitchy in a straight line and will want to follow a lot of lines/ruts/cracks on the road, but it will turn in better than anything you have driven before.

You do realize your trying to give advice to a not only an e30 guru, but a certified instructor. Im gonna go out on a limb and say, as usual..whatever Jim says is what you want to do. Its not what "someone told him" its years of racing spec e30.

[jlevie]

You do realize your trying to give advice to a not only an e30 guru, but a certified instructor. Im gonna go out on a limb and say, as usual..whatever Jim says is what you want to do. Its not what "someone told him" its years of racing spec e30.

I may not always be right, but in this case I know I'm right and those are the numbers I and others use on Spec E30's. And we use the same front camber.

[FredK]

Jim, are you still using the eccentric bolts and plates that are available, for example, from AKG? Or are there other kits that hold their adjustment better?

[FLG]

I may not always be right, but in this case I know I'm right and those are the numbers I and others use on Spec E30's. And we use the same front camber.

Whatever you say is generally gold. I even add "jlevie" to most of my Google searches and hope you responded to a post when I'm trying to diagnose issues.

Jim, are you still using the eccentric bolts and plates that are available, for example, from AKG? Or are there other kits that hold their adjustment better?

Correct me if I'm wrong, but I think a lot of the "loosing adjustment" comes from just the trailing arm bushings being flat and binding. I know condor makes a tapered bushing which eliminate binding and will probably solve them getting loose.

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[SkiFree]

Correct me if I'm wrong, but I think a lot of the "loosing adjustment" comes from just the trailing arm bushings being flat and binding. I know condor makes a tapered bushing which eliminate binding and will probably solve them getting loose.

You are slightly off as far as ALL bushings benefiting from tapering. The Condor bushings are tapered because it is necessary when using UMHW in this application. If you've ever chalked up a hunk of UMHW up on a lathe you'll find it can be difficult to machine smooth because the material catches. This isn't bashing Condor, they simply have fixed an issue inherent to the material they are using.

As has been oft mentioned, "riser bushings" are not a cure all for fixing rear camber/toe. They certainly help, but to dial things in some form of the weld-on adjusters are needed.

Using both the "machined, not bent" cam adjusters and the posi-lock adjusters on the 5 cars here along with the feedback from many many others have led me to believe that many of the issues are often alleviated via basic car maintenance (i.e. proper torquing, double nutting, trailing arm sleeve measuring, due diligence while initially welding the kit on, and a general helping of common sense). Jim has some very nice suggestions, and most seem to find what way that best works for them.

[mulletman]

Do whatever Jlevie says. I've not yet seen him give advice that was bad.

[jlevie]

Jim, are you still using the eccentric bolts and plates that are available, for example, from AKG? Or are there other kits that hold their adjustment better?

I am still using the eccentric adjusters, but I have added a lock mechanism to prevent the bolts from turning. That has eliminated changes in the adjustments.

What happens is that the up and down movement of the trailing arms puts torque on the bolts. That causes the bolts to loosen and the adjustment to change. If the bolts are locked into position after the alignment is complete, the adjustments can't change. I'm of the opinion that this problem exists with the eccentric and the lock plate designs, though it would be easier to eliminate with the lock plate design by welding the bolt to the inner lock plate.

[JohnH]

You do realize your trying to give advice to a not only an e30 guru, but a certified instructor. Im gonna go out on a limb and say, as usual..whatever Jim says is what you want to do. Its not what "someone told him" its years of racing spec e30.

Rear camber angles are highly dependent upon the tire width and aspect ratio and tire pressure. The SpecE30 regulations only allow 205/50-15 or 205/55-14 tires on 14x6 14x6.5 or 15x7 wheels. Those are fairly tall tires by todays standards. I wonder what the OP is running.

[mr2peak]

You should do it. They will dramatically change your tire wear, and give you the ability to hit these numbers. I recommend doing the braided brake lines at the same time.