Extreme body roll - tire wear & oil starvation

[HAZE33]

Hey guys, Just got back from the track with my '95 318ti. Stock motor, roll cage, ebay lowering springs, stagg (ebay) shocks, and 205 dunlop star specs This thing has ridiculous body roll:




I don't mind the body roll, except it's causing some problems. The outside edge of the tires are wearing much quicker than the middle/insides. I've shimmed the front struts to the max for ~3.0* negative camber, and stock rear camber (maybe -1.0?).

The second problem that just showed up is some serious oil starvation during quick transitions (cornering). Does the M42 engine usually have problems with oil starvation? Do you think it may be partially caused by the body roll throwing the oil around in the pan? How much can I overfill the engine safely to prevent this?

Now for suspension. I figured these ebay springs would at least be stiffer than the stock suspension. But I have never driven the car with stock springs, do they usually roll this much on stock springs? What's the best approach to reduce the roll? I'd like to do H&R race springs, but I don't want to upgrade the shocks (which sounds necessary for springs that stiff). Would the H&R Sport springs be stiff enough to reduce it? Swaybars?

I know that's a lot of info & questions...but any input would be appreciated.

[M-technik-3]

Suggest going to a Ground control set up for budget and using M3 front strut style anti sway links welded to your struts. That will help the front. How are rear subframe bushing and trailing arm bushings?

[thebmwnut]

do not weld tabs on your shocks, your shocks will most likely not survive and if your weld goes to deep you could put a hole in it and they are pressurized with gas. first thing that comes to my mind when I saw the picture is you are sideways, way too much oversteer , smoother steering input or a really big front sway bar on full stiff. I run a Hotchkis, on my club sport, rest of suspension is stock except for my koni shocks and I still fight body roll but it is much more manageable with the big bar, I can even get a little oversteer .

[joe1602]

OK, First off, take a look at my thread "Push, Push, Push" in the autocross section. I am currently experiencing these problems with our 99 in autocross. I have the H&R race springs with Koni adjustable all way round. I have just purchased a used Eibach 28mm adjustable sway bar and am waiting for the proper bushings to install. Rest of rear suspension is stock. I am on 225/50/16 Hankook Ventus Rs-3 tires. Have an event this weekend and am hoping the bar will be installed so I can see if it is helping with the body roll. We are picking up the inside front tire while cornering hard. At this point, I don't like the H&R springs. They lower the car nicely but they still feel a little soft for the car. +1 on the Ground Control spring set. If I still don't like the amount of roll the car has with the new bar, I am going to go to the ground control coilover kit (made specifically for the ti, around $450, just the springs and hardware and goes with shocks that are on my car). I have a picture posted that shows how much our car is leaning even in moderate corners. I also have the front shimmed to the maxx, about -3.5. I still push and still lean a lot. Will keep you posted on how the new bar does this weekend. Good luck.

[HAZE33]

Thanks for the input guys.

Rear subframe & trailing arm bushings are original. I'm sure they could use some love, but I'm not noticing any weird movements from the rear end.

You're right, in the first picture I'm overdriving the car. Here's another example of the amount of roll under more controlled cornering



Joe, I'm going to look at your autocross thread right now. So that picture you posted is with the h&r race springs & konis? I'm surprised to still see that much roll! Have you ever noticed any oil starvation/pressure drops under corning like that? If you have in car video with a view of the oil pressure gauge you might want to check it out.

That's my biggest concern with all of this - the oil starvation. Is this a common problem with the M42? How much do you think I can safely overfill it?

This is supposed to be a crapcan racer, so coilover kits are not an option right now... I'd like to run stiff springs with cheap/oem shocks, but I know that isn't ideal... it seems better than destroying the outside of the tires & having oil pressure drops though...

[thebmwnut]

ok im going to try and be nice about this. The guy I bought my 95 club sport from only did performance driving with BMWCCA and he was an instructor only mods was shocks and larger/better front brakes. I run the same car in auto-x or solo and only thing I have changed minus going back to stock brakes is add a front bar and more adjustability with koni shocks. It is all about your driving input. Best advice I can give you is the BMW's love to turn under power. I have always told people its brake (in a straight line), bake on power then turn. remember brake, power, turn. keep telling yourself this. brake , power, turn. Its not the car its you. BTW I am carrying the front inside wheel 4 to 6 inches in hard corners under power. The front tire being off the ground is not the problem. I always said if the front tire is not off the ground im not going fast enough or doing to corner correctly.

[joe1602]

nut, thanks for the input. I am well aware of my limitations as a driver and keep trying to improve every time I'm out there. I try to brake, power, and turn, but often times I get ahead of myself, my son is better at it than me. (That's why he's consistently faster than me!) I just don't like the way the H&R springs feel to me, they feel too soft. I also have a 2002 325Ci that I have installed Koni's and H&R race springs on and the ride is much stiffer and feels a lot better. The ti's H&R springs almost feel like the stock springs with the car just sitting a little lower. I will try to remember this weekend: Brake, Power, Turn!

[TobyB]

Stiffer springs.

Yours are letting the body roll a LOT, and that unhooks the rear suspension.

With the E30s (also a rear trailing arm) we're up to around 600 lbs/in in front,
700 lbs/in in back. Some go stiffer.
Stock car springs can be adapted to work, and they come in an almost- infinite number
of rates...

Also, lowering helps (to a point) to get the roll centers down.

t

[joe1602]

Toby, I agree about the springs. The H&R for the ti just don't feel stiff enough. I have been kicking around the idea of buying some spring rubbers (like they use in NASCAR) just to see what the effects on the springs and handling are. Not sure if it is a good idea or not but it may be an inexpensive way to increase the spring rates. I have not done it yet because I still haven't seen the effects of the new front bar yet. (As I am still waiting for the proper bushings to arrive in the mail). I am hoping to have it in for this weekend & will post my findings after this weekend.