So...I just came back from Laguna Seca (1 year after my wreck there mind you), and I am getting rubbing frequently, specifically T6, T8a. I do feel like I am getting a ton of roll. I have 18x9s with 255/35 R888s. 10mm spacers in the rear. The rear body is extermely modified from stock due to the wreck, and I think most of the rubbing is on the rear bumper.

I ended up with a 1:48.5 as my fastest (also my fastest to date), but I know that I had left a couple of seconds on the table because I was getting so much rubbing in T6 so had to back off...bad place to do so before the big hill and whatnot.

Spring rates 500/600 on TCK DAs. Compression: 10F/7R, Rebound: 1/2 turn back from full stiff F and R. Stock swaybars. Camber 4.25F/3R.

Here are the photos, Is the car just too soft? Springs? Sways? It still has to be street bearable (no chance of getting a tow vehicle anytime soon). Please ignore the ugliness for now...it'll be pretty again soon.

T5 I think (no rubbing...but T6 it compresses even more):
http://farm3.static.flickr.com/2379/2348539809_89d0e4b595_o.jpg

Inside of T8a:
http://farm3.static.flickr.com/2295/2348539827_23a3fcc5d3_o.jpg

Seems like the simple solution would be to remove the rear spacers..? Do you need them for inner clearance? I wouldn't think you would.

To answer your question, though - A larger front bar would really help reduce the body roll, and improve turn-in and front-end grip overall.

nice custom laguna exhaust :rofl. i still need to figure out what im going to do for mine

Seems like the simple solution would be to remove the rear spacers..? Do you need them for inner clearance? I wouldn't think you would.

To answer your question, though - A larger front bar would really help reduce the body roll, and improve turn-in and front-end grip overall.

It would seem so except that inner clearance is an issue on the driver's side because of the damage from the wreck. However, I am also running an 8mm turner spacer up front too to balance it out.

I should have mentioned that the ride heights turned out almost exactly equal all around when corner balancing, so I am not sure if not having any rake as others have mentioned plays into this.

I had been resisting swaybars primarily because I wanted to learn the car with the suspension before adding another variable. A couple of years with the DAs, I am now comfortable enough with the setup and am open to the option of sways.

So...fronts only? The car does push especially in the tighter corners and I need to carry a large slip angle to get the darn thing to power out of turns sometimes. Wouldn't only getting a front bar make that worse?

nice custom laguna exhaust . i still need to figure out what im going to do for mine

Thanks! I got sick of tripping sound at 93.xxdB and having to short-shift to 4th up the hill to T6

So...fronts only? The car does push especially in the tighter corners and I need to carry a large slip angle to get the darn thing to power out of turns sometimes. Wouldn't only getting a front bar make that worse?


That is what intuition would tell you, but that is not the way these cars seem to work. A stiffer front bar can often help front grip a lot. It is definitely worth a try.

Have any pictures of the car in the paddock? Ride height looks too low to me, but it's harder to tell from a picture on the track.

I think that taking off the mouldings upset the 50/50 balance.

Doesn't the exhaust ruin the weight balance of the car?

Doesn't the exhaust ruin the weight balance of the car?

Yes. I'm amazed it can even keep the front wheels on the ground. :rolleyes

Have any pictures of the car in the paddock? Ride height looks too low to me, but it's harder to tell from a picture on the track.

None in the paddock, but a couple on straights:

Right before T6 at Laguna:
http://farm3.static.flickr.com/2124/2350152616_870713e165_o.jpg

Between T2 and T3 at Sears:
http://farm4.static.flickr.com/3236/2349321989_b27184a0b3_o.jpg

Here's a picture on the outside of the corkscrew to re-illustrate the amount of roll/compression.
http://farm4.static.flickr.com/3056/2350165198_cf20765d69_o.jpg

If you can tell me what hard points I should measure from the ground, I can do that (I have an intercomp height gauge I got a decade ago).

Bassem

On that last pciture, I can't imagine not rubbing.

B,

The reason you have too much roll is that your springs are too soft ;)

I'm running 600#f/700#r in a car that's what did we decide (?) 150# lighter than yours and I still get similar compression in 6 & at the bottom of the corkscrew.

Here's a comparison of what I have:
http://gotbluemilk.com/web080318/127/images/HT4U1577.JPG
vs
http://farm4.static.flickr.com/3056/2350165198_cf20765d69_o.jpg

Not a huge difference, is it?


If you can tell me what hard points I should measure from the ground, I can do that (I have an intercomp height gauge I got a decade ago).
I measure from wheel center to lip, which is now probably not the same since a moderately aggressive fender roll. I *think* you're looking for something like 12.5" front & 11.75" rear, but don't quote me on that. One of the best people to talk to about it, locally, would be Tony Colicchio (TC Design)

What do your bump stops tell you? (If no bumps them wrap a nylon tie around the shock shaft.) This will give you an idea about where you are on suspension travel.

Time on a skip pad to ensure the spring package is balanced and not bottoming is a good idea as well.

On that last pciture, I can't imagine not rubbing.

Oh yeah...boy does it rub..sounds like a chainsaw for a half second or so...

I'm running 600#f/700#r in a car that's what did we decide (?) 150# lighter than yours and I still get similar compression in 6 & at the bottom of the corkscrew

Saw your pics Jeff and thought that the amount of compression looked similar. We may be talking a few mms of difference though between rubbing and not rubbing. I do have a set of 5mm spacers I could try to use instead I guess. I actually think your car is a little lower than mine too.

What do your bump stops tell you? (If no bumps them wrap a nylon tie around the shock shaft.) This will give you an idea about where you are on suspension travel.

Time on a skip pad to ensure the spring package is balanced and not bottoming is a good idea as well.

Will have to look, don't believe I am on them though. Reason being that there is still some compression left in them after the rubbing starts. Also, while a skid pad will tell if the package is balanced, it really cannot help with mid-corner bumps, which is what is primarily causing the rubbing.

Thanks,
Bassem

Just wanted to say your car looks really nice. Would rolling the fenders more solve the problem, or could you get a widebody kit?

I would raise your ride height...it looks like it could be a little low to me. Due to the funky front suspension geometry, you may find the car rolls less at a slightly higher ride height. Cheap and easy if it solves the problem.

Just wanted to say your car looks really nice. Would rolling the fenders more solve the problem, or could you get a widebody kit?

Thanks...I guess. That comment a wisecrack? I'll take the compliment anyway :). The guys here talked me out of a widebody...and my bank account is thankful for it. The fenders have really been massaged to almost their limit. I think adding a couple of spacers behind the rear bumper (to push it slightly back) may be the ticket for avoiding rubbing that. Still touch the fender though at the limit.

My main concern is roll and if the setup is too poorly sorted now.

I would raise your ride height...it looks like it could be a little low to me. Due to the funky front suspension geometry, you may find the car rolls less at a slightly higher ride height. Cheap and easy if it solves the problem.

Ok..any suggestions for how much? 5mm or is that too little to notice? Visually the car looks like it is too high, but it just could be the 18s playing tricks on my eyes. I'll measure the heights tonight too to see how close they are to the accpeted "ideal".

Bassem

I *think* you're looking for something like 12.5" front & 11.75" rear, but don't quote me on that.

After Sushi/Sake update: Fronts are at 12.75", Rear at 12". Considering that the sheetmetal has been pulled up quite a bit, that seems real close to those numbers....

What is the offset of the rear wheels? Do you really need the rear 10mm spacer?

That comment a wisecrack?
Bassem

No, I really do like how your car looks( the suspension/wheel combination and agressive stance). Especially that pic of your car when compressed at the bottom of the corkscrew, the tops of the wheels are nicely tucked just inside the fenders with nice amounts of camber, looks exactly like the bmw factory e36 race cars.

just get some swaybars

just get some swaybars

+1

What's the holdup for not running a huge pipe of a front sway bar?

I'm not sure you need stiffer springs. The whole idea is to run the softest springs you can without any bottoming issues. Rubbing issues, before bottoming your suspension travel, are ride-height / bodywork items. If you mask that problem with stiffer springs then you're just moving backward by reducing the tires ability to stay connected to the track and throwing away suspension travel. It would also greatly reduce the "streetability" of the car which you mentioned you wished to maintain.

After you've dealt with the ride height (5-10 mm minimum), it's sway bars or should I say sway bar. All you need is a large adjustable front bar like an Eibach, GC, etc. If you want to go both front and rear then make sure both ends are adjustable and, if they're large like my RD bars, then start with the front at full stiff and the rear in the middle.

As others have said the E36/E46 require the opposite of the "general" rule-of-thumb" to reduce understeer. BMW actually built understeer into the geometry as the suspension compresses to appease their lawyers and ensure the cars would plow off the road front-end first rather than the litigation-happy tail-end first.

My picture below is with the front bar at full stiff and the rear at full soft to address an issue that was specific to the situation. A middle setting in the rear would have kept the inside front wheel down a little by reducing the compression on the outside rear which is what you need to do to reduce/eliminate the rubbing after you've raised your ride height.

Also as someone else mentioned (Mr. Watts, IIRC) you are likely running so low that your messing up the front-end geometry even more than the stock setup which already needs help. Don't compare your ride height to most professional E36/E46 race cars as they typically are using altered lower control arms etc., to offset/recoup the negative geometry changes brought on by lowering the car.

Regards, Alan

I'm not sure you need stiffer springs. The whole idea is to run the softest springs you can without any bottoming issues. Rubbing issues, before bottoming your suspension travel, are ride-height / bodywork items. If you mask that problem with stiffer springs then you're just moving backward by reducing the tires ability to stay connected to the track and throwing away suspension travel. It would also greatly reduce the "streetability" of the car which you mentioned you wished to maintain.

That sounds good and is the approach I have been trying to use. The bodywork, while is near the limit of what can be done, is really not the issue, but more a byproduct of the issue as I see it. And that is too much roll. I prefer more compliance not just for the ability to drive the car to the track, but because it makes the car much easier to control on bumpier track sections, especially braking zones.

In any case, I will follow both suggestions (stated by all of you) of trying a taller ride height as well as a stiffer front sway bar to help keep body roll in check. As it is I am still using the outside of the front tires a lot more than the relatively large amount of camber sensibly should allow, which is related to the excessive amount of roll I seem to be getting.

Thanks,
Bassem