I am hoping to increase my rear traction, as I am having a hard time getting power down. Car is setup with a GC coilover setup, 440/660 spring. Front IE bar on soft with M3 mounts, no rear bar. I'm running 245/40/17 RE71r's. 32/30 psi. Even in a straight line, I'm able to get the wheels to slip on aggressive gas. Now, I'm running a 270hp N52, but nevertheless, seems like the rear should be grabbing better. I'm running -2.5 in front camber, -2.5 in rear. I'm thinking maybe I should reduce the rear camber to get the tire more square with the pavement. Given the high hp. I'm running, seems like I would gain more net in an autocross setting. Anyone have any advice? I really hesitate to increase rear spring, but anyway, the power induced camber change is pretty noticeable.
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Your spring rates are quite a bit too low to eliminate the rear sway bar in my opinion. Put in a 19mm rear bar or up your spring rates, that’s a street spring rate setup you are running anyway.
As for camber, a good target is typically -2.0 in rear
My car weighs 2250#, I run 700/900 spring rates, and I make 280rwhp, no rear end grip issues. Also, no rear sway bar
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Thanks guys. So I think I will take the rear camber down to 2-2.25 and see the results. I am running about 1/8" toe in on the rear. I have the stock rear bar installed but not hooked up, so I guess I can experiment with that as well. M3, I think you are right about needing more spring, but its something I would like to add last if these other changes don't resolve the problem.
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Although I have an E30 M3, my experience may be helpful for you. I am running a GC setup with SA Konis and 550lb front springs and 750lb rear springs with 22mm front and 19mm rear sway bars. Tires are 225/50R15 Pirelli Troefo R. On the track I found I needed to set my rear Konis to full stiff and then back off 1/4 turn. I run my car at Portland Int'l Raceway which is a fairly smooth track with a couple of corners that are bumpy on exit.
I don't experience any rear wheel hop and can lay the power down throughout the corner. Car is neutral to slight oversteer. .1990 M3
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If loose, I also have a theory in why people have problems.
A longated hole in theory has only about 30% of the clamping area. That’s if the person longating the holes didn’t get sloppy. Next most trailing arm bushing sleeves are aluminum, so now that 30% clamping surface mushrooms the aluminum and the bolt comes loose. And people don’t crank the shit out of them!
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