I am looking for some feedback/advise on set up for my 95 M3.
Here's what i have now.

800 lb front 2.25 X6
850 lb rear springs 2.25 X5
Adjustable rear perches
TCkline DA's front and rear
Adjustable front and rear sway bars.
Front set to full tight
Rear set loose
Shocks set soft in the rear and firm on the front, both rebound and compression.
Adjustable rear CA's set to -2.5
front set to -3.5
245-45 hoosiers front and rear on 17 x8.5 kosei's front has 5mm spacer

Car is corner balanced with 51-49 front rear and 50-50 cross weighted.

I am suffering a fairly loose rear end in tigh, low speed corners, in both directions, but particularly right turns. I had the same problem with a 600-700lb set up. I thought decreasing the diference to 50 vs 100 lbs would help. It actually made it a little worse.

I softened the rear shocks considerably and that helped to the point of inducing a little push if corner entry is not perfect. But the rear still slides.

Any suggestions?

Thanks

Bruce

- where in the corner do you feel the looseness? (entry, apex, exit)
- front / rear toe setting?
- stock diff?

how big is your rear sway bar? just curious

- where in the corner do you feel the looseness? (entry, apex, exit)
- front / rear toe setting?
- stock diff?

Mid to exit in some but early in uphills

Front toe is neutral
rear set to 3/32
diff is a 3.73 70% locker

How / what are your RTABs?

How / what are your RTABs?

RTAB'S??

How / what are your RTABs?

sorry. The lower control arms are spherical the uppers are oem. Both are new.

how big is your rear sway bar? just curious

Curious about that too. I had RD bars front and rear with 600/700# springs and ended up going to a factory E36M3 rear bar, which seemed to bring everything into line.

Curious about that too. I had RD bars front and rear with 600/700# springs and ended up going to a factory E36M3 rear bar, which seemed to bring everything into line.

I don't know the thickness, but I have been told this before. I saved my OEM rear bar for that reason.

Thanks

Curious about that too. I had RD bars front and rear with 600/700# springs and ended up going to a factory E36M3 rear bar, which seemed to bring everything into line.

I don't know the thickness, but I have been told this before. I saved my OEM rear bar for that reason.

Thanks

Disconnect the rear bar, and see how it feels. Easy to do the test without too much work. My car is experienceing similar symptoms (I have JRZ DAs, 800# front, 850# rear, eibach front, no rear bar, similar diff). It seems that getting on the power in tight turns, the rear just breaks loose. I'll be working on the issue at an event June 22-24, so I'll report anything that I find.

Disconnect the rear bar, and see how it feels. Easy to do the test without too much work. My car is experienceing similar symptoms (I have JRZ DAs, 800# front, 850# rear, eibach front, no rear bar, similar diff). It seems that getting on the power in tight turns, the rear just breaks loose. I'll be working on the issue at an event June 22-24, so I'll report anything that I find.

That sounds like a good idea. I'll try that. I should stiffen up my shocks too, no? They are very soft now. Both rebound and compression?

That sounds like a good idea. I'll try that. I should stiffen up my shocks too, no? They are very soft now. Both rebound and compression?

Just disconnect the rear bar, leave everything else alone for the first test. One change at a time.....

Just disconnect the rear bar, leave everything else alone for the first test. One change at a time.....

Good advice.

Thanks

Id attempt disconnecting the bar too, how was beaverun?

Beaver run was fantastic. The weather was perfect. Greg Peluso was there and ran very well. I managed a third place both days behind the C5 and a well driven 911 on Saturday.

On Sunday I qualified pole, but I blew the start and never recovered. Both the Vette and Cobra got in front and stayed in front for all 28 laps. My tires wer beat and so was I. I did manage a 106.9 though.

Brought it back in one piece. That's the most important thing.

RTABs? You talked about control arm sphericals, but what about the trailing arm bushings? Assuming those are OK, you might want to consider taking about 100# out of the front and 200# out of the rear springs if you want to keep running a bar. That rear rate with no rear bar is probably closer to right, but with the bar it way too stiff.

RTABs? You talked about control arm sphericals, but what about the trailing arm bushings? Assuming those are OK, you might want to consider taking about 100# out of the front and 200# out of the rear springs if you want to keep running a bar. That rear rate with no rear bar is probably closer to right, but with the bar it way too stiff.

Yes, I forgot the trailing arm bushings are also new. The bar sounds like the issue.

remember, especially with relatively small-tired cars, softer is usually faster (to a certain extent, anyway) your setup seems WAY oversprung/overbarred. For grins, try 650# front 750# rear with soft bars and compare lap times. You might be pleasantly surprised.

remember, especially with relatively small-tired cars, softer is usually faster (to a certain extent, anyway) your setup seems WAY oversprung/overbarred. For grins, try 650# front 750# rear with soft bars and compare lap times. You might be pleasantly surprised.

I had 600/700 on but opted to go stiffer because of my new motor. Right now I am running a slightly modded 2.5. Stickly is almost done with my 2.9 stroker. I anticipated needing stiffer springs for that kind of power. I can easliy go back but even with the 600/700 set up I was having the same trouble, especially at Summit exiting the last right in the carousel.

Where would you set the front sway bar on this set-up? Thanks

for an e36 with at 650/850, I would run a GC bar pretty heavy and no rear bar. At 600-650/700ish, a small rear bar and less front bar might work. Adjustable bars should be used for fine tuning though. Get the springs to do most of the work and get the car close, then use the bars (assuming front and rear) to dial in the characteristics you like.

for an e36 with at 650/850, I would run a GC bar pretty heavy and no rear bar. At 600-650/700ish, a small rear bar and less front bar might work. Adjustable bars should be used for fine tuning though. Get the springs to do most of the work and get the car close, then use the bars (assuming front and rear) to dial in the characteristics you like.

If I understand you correctly. With 800/850 no rear bar and stiff setting on the front.

What if I am running slicks or wider hoosiers? Wouldn't the extra tire grip require some rear bar?

What if I am running slicks or wider hoosiers? Wouldn't the extra tire grip require some rear bar?

Why? Not aying you're wrong ... just curious as to the logic behind this.

Currently running hoosiers. Slicks would give extra grip. Just thinking the rear would stick better by virtue of the tires alone. But that's why I asked because I DONT know.

Why go with 70% lockup by the way? That seems a bit steep to me.

It was recomended by VAC. I wouldn't go that steep again though.

Hard to say on that. Normally more grip from the tires will require (or at least reward) more spring rate---whether from more spring or a stiffer bar setting. Thats all part of the fun of setting the car up though. A DOT R setup will be different from a slick setup.

Thanks folks for all your input.

Bruce

Another thing I learned from my days racing mustangs was this. When I am pushing in predominately one direction, adjusting the weight on the wheels will help dial that out.
For example:when i would understeer to the right, I would raise the right rear and left front and visa versa for the opposite corners. That did help but it was a very different car. Would this work with the M3?