Need Advice on Eliminating Body Roll *Tight Budget*

[Lof8]

I suggest some UUC Swaybarbarians sways. Their rear bar is adjustable. I ran a similar spring/shock setup as you with the UUC sways for several years. It was a nice neutral-handling setup. Some front camber will help too.

[matthugie]

There is always room for improvement in driver ability, even Sienna would go over telemetry after a practice or race session to find ways to be faster..

Sienna Miller? Giggidy!



That aside, I completely agree with the rest of this post. The best thing you can do is learn to drive your car. Learning to cope with understeer and getting the car to go where you want will serve you much better in the long run than tuning your car right off the bat.

Oh, and OP, I'm not 100% on this, but I think the rack swap might actually put you in a higher class.

[Emre]

Wow...lots of misinformation in this thread.

Everybody knows that "increasing front roll stiffness (via springs or sways) induces understeer." But that's just theory. That assumes an ideal suspension. And the E30 suspension is far from ideal.

If you want to maximize front grip on an E30, you need all the roll stiffness you can get (and pretty much all the negative camber you can get). That's because McPherson struts undergo dynamic camber loss. So, the more the front end rolls, the less negative camber you have, and the less grip your outside front tire has.

That's why you can't go by pure theory. This isn't a formula car with double-wishbones all around, so you can't just parrot whatever you've read in one of Carrol Smith's books.

The OP absolutely needs to decrease roll over the front axle. Higher spring rates and thicker sways are part of the solution. There's also the trick of using reverse stagger to overload the outside rear tire under load, which helps under-powered RWD cars rotate under throttle (assuming the LSD locks up tight). What works for a Civic won't work for an E30.

[Nsquared97]

Oh, and OP, I'm not 100% on this, but I think the rack swap might actually put you in a higher class.

It does, either prepared or SM, both of which would be aweful. IMO, it just gets rid of a huge handicap the E30 has compared to the rest of the *top* STX cars anyway. Is it legal? No. But is anyone going care? Not really. Plus there are plenty of other things he could do to make that car much more competitive than a rack swap.

Also, just wanted to throw my $0.02 in on doing just a rear sway. I can't speak for your setup, but on my completely stock suspension with 225 slicks, I get enough body roll to unload the inside rear tire enough that the LSD can't lock enough, and get inside wheel spin. It's not all the time, but in 1-2 corners an event. Adding just a rear bar would aggrivate that, but again I can't say how the H&R race springs would work to counter that, and I am on stickier tires.

[lcoleman]

Sounds like steady-state understeer to me. The best thing I found to help were camber plates...someone on the forum was selling them for like $100 then, you should be able to get those and have enough left for a rear sway as well. I wouldn't change the front bar, just add a rear one.

[jntar]

I agree camber plates would really help out, but everything I've read and heard about autocross in the e30 states Not to upgrade the rear bar. In fact 99% of the people I've talked to and read from state to disconnect the rear bar and stiffen the front...So which is it? How many of you have tried both ways?

[evandael]

i have read of positive results with super-stiff rear springs, dampers to suit, and stock/NO rear sway bar.


also, dropping (ie, lowering) the outer tie-rod and control arm connections would aid in roll-center correction and bump steer. also you could consider going to a strut-tube mounted sway link (as opposed to the less effect e30 control-arm mounted link).

[lcoleman]

Autocross = no rear bar to keep the rear wheel from lifting
Track = rear bar for neutral/loose tendency

If you're autox only, I'd consider keeping the stock rear or disconnecting it and upping the rear spring rate (if possible). Seriously though, camber plates. can't emphasize this enough.

[djjerme]

Autocross = no rear bar to keep the rear wheel from lifting
Track = rear bar for neutral/loose tendency

Actually, many of our PRO3 guys are running with the rear sway disconnected and anywhere from 850-1000 for rates. But I would never suggest that for a street driven car..

Stupid autocorrect, Senna..

[JBedo]

Im running a 318 in stx right now as well. Im currently running bilstein sports with some ST springs (remember the ones going for 70 bucks) from ebay. M3 cabs and all new shock and strut mounts. O, and stock sway bars with falken azenis on the stock steel wheels. Nothing special at all but my car rotates very well. Especially the faster I go. It leans like a bus but without putting it into a full drift I can touch the brakes at turn in and it rotates right around. Ive been autocrossing, doing track events and racing shifter karts for well over 10 years so im going to have to agree, get some seat time.

[Fooshe]

Lots of opinions will confuse just about everyone. Here is just one person's opinion.

To improve your times:

1) Corner weight your car! ALL balance problems start here.
2) Understand that some body roll is good.
3) Master trail braking
4) Improve your inputs to maintain balance. Pushing any car too hard is going to produce under/oversteer with even if it is prep'd perfect.
5) For what you are doing, look into Ksport's Coil Over front kit. Leave your rear set up with Bilstien's and H & R race springs as is.
6) Consider your tire choices and dial in your PSI's.
7) Set camber up front.
8) SEAT TIME!

[BlackbirdM3]

A set of camber plates will give you the needed front negative camber, you also want to run as much caster as possible. The problem here is if you run the Spec e30 Ground Control race camber/caster plates, it moves the front roll center below ground level. That will make all your current handling issues worse and magnify the camber loss as the strut compresses, increases body roll, and it will cause your spring rate to act like a falling rate (it blows through its travel faster, the more it compresses.) There is a solution however. If you are running 14 or 15 inch wheels, you will have to do a couple things to raise the front of the car up. 1, take your brand new caster plates and cut the mounting studs off them. Replace those studs with ones long enough to clear a 1 inch spacer that fits on top. 2., You need to have a 1 inch spacer machined to fit on top of the camber plate to lift the front of the car back to about where it would sit now. No, its not a simple solution, but my setup is exactly like yours only I'm running TC-Klein Konis rather than Bilsteins, and I have the Spec e30 plates, and they over lower the car. (I did the math.)

Now, if you happen to have bigger wheels such as a 16 or 17 (I can't recommend either for a lot of reasons.) you can get the easily found roll center spacers that fit between the lower control arm and the strut housing doing exactly the same job as the spacer I had to have custom made. I don't know that going to super stiff springs will do you much good. You need to have some suspension compliance so irregularities can be absorbed rather than causing the car to skip. You also need way uprated dampers to control the higher rate springs. (Even a set of stock Bilsteins or Koni Sports don't have enough damping for a set of H&R Race springs.)

All that said, with stock sway bars, H&R race springs, GC spec E30 adjustable camber/caster plates, Treehouse racing lower control arm bushings, my M3 is neutral pretty much everywhere. I run -2.75 degrees camber, as much caster as I can get (about 10 degrees), and 0 toe. I haven't had a chance to get the spacers installed (I picked them up Friday afternoon and I still need to take the car apart to modify the strut mounting studs.) I also run a Sparco front and rear shock/strut tower brace. I am thinking about upgrading my swaybars in the future, but I'm going to wait and see how it does with the spacers installed. I had 3 class wins while running street tires against guys on Hoosier A6s last year. As it is, my car is pretty dang fast and very easy to drive. Seat time goes a very long way, but as a friend of mine proved, if you have a solid car, a decent driver can get very fast in a very short period of time. My friend had never autoXed before in his life, he came to a school I was instructing at and by the end of the day he was within 1 second of my time in my car which he had never driven before.

Will

[brent5631]

Blackbird, where are these roll center spacers for the ball joint sold? I've been looking.

[Berkut]

Roll center spacers are M3 only, won't work with a standard e30 strut that is one piece, no?

[BlackbirdM3]

Blackbird, where are these roll center spacers for the ball joint sold? I've been looking.

VAC has them http://store.vacmotorsports.com/vac-...cers-p398.aspx

Lee Vuong has some as well http://www.massivebrakes.com/accesso...llCenterSpacer

Either one of them requires big wheels otherwise there is contact with the wheel.

I was forced to do something like this (not my car in the pics)


Will