Need Advice on Eliminating Body Roll *Tight Budget*

[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?

[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.

[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.

[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.

[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.

[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.

[ak-]

I'm already 1/4" total toe out. I'll look into the CABS.

In that case maybe hold off for a while and opt for GC camber/caster plates and have the best of both worlds!

[jntar]

Toe-out would probably be the most affordable approach.
M3 CABS too since it offers more dynamic camber considering the caster change.

I'm already 1/4" total toe out. I'll look into the CABS.

[ak-]

Toe-out would probably be the most affordable approach.
M3 CABS too since it offers more dynamic camber considering the caster change.

[iamsam]

Wouldn't that make the more prone to oversteer? On the very tight courses we run here, anytime oversteer occurs you lose time. I need some type of balance which is going to be tough.

It absolutely would. But to reduce understeer, you will need to introduce oversteer. The E30 is naturally prone to understeer, so you will find that it won't create a problem. I speak from experience, as I had H&R Race/Billy sport on my 318is, and at the autocross track, it was understeer city. I would plow my front tires through the entire course. Then I installed ST swaybars (I can't remember the actual specs) but WOW did it make a difference. MUCH flatter cornering, MUCH less tendency to understeer, and excessive oversteer was not even a problem that entered the situation.

I used Kosei K1 15x7s and 205/50/15 Dunlop Direzza DZ101.




Man, I kinda miss my car back when it was low/stiff. Now it looks more like this:

[jntar]

Two things I am noticing right off the bat:

1) You have a lot of mod's already done on the car.
2) This is your first season.

What is your goal right now? Is it to win at Autocross or build a kick-arse E30? You have to decide which is your goal. If you want to win at Autocross, then take your combination you have and learn to drive the piss out of it. In fact, you may be better off to go back to stock on some of the mods if it will put you in a more competitive class. Learn to drive what you got, even if you feel it's got issues. I have seen good drivers take piles of crap and beat out several well sorted machines; in both AutoX and wheel to wheel.

You are collage student right? If you want to get better at say math, do you go buy top of the line graphing calculator, the best mechanical pencils and the highest quality, hand woven paper? No you study the hell out of math. Take that $300 and buy a good Autocross book (or rent one from the library). Then take the leftover and buy some Pizza and Beer. Then you take the pizza and beer and offer it to the guy with the fastest, consistent times at the event in exchange for some coaching and possibly even have him ride along on one your runs. Trust me, you will gain more than you ever would spending $300 on go faster bits.

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..

Thanks for the input. I do have a "mentor" who runs a 318i in gstock. He has won our regional before. There is also a driving school next month on the 6th followed by our next autocross event on the 7th. I completely agree I will need to get better.

Goals, I am not going out to win nationals or anything. I'm more in this for the experience. I am a good driver. Been mountain road driving for 15 years, but I feel it's time to take it up a notch and that is autocross. After that is hitting the track.

The car is understeering because; a) you don't have enough rear sway, and b) don't have enough front camber. With money being a strong consideration I think you'd get the most bang for the buck with a set of Bimmerworld 22/19mm sways and a set of GC Spec E30 camber plates. Then get the car corner weighted and fiddle with spring pads to improve cross and front/rear balance.

Thanks for the input. I am leaning to a swaybar set and camber plates or springs and camber plates. We'll have to see which I can get in my budget.

rear swaybar. Find the largest used one you can, and beef up the mounting points. It will definitely be under $300, and it will nearly eliminate your understeer.

Wouldn't that make the more prone to oversteer? On the very tight courses we run here, anytime oversteer occurs you lose time. I need some type of balance which is going to be tough.

[iamsam]

rear swaybar. Find the largest used one you can, and beef up the mounting points. It will definitely be under $300, and it will nearly eliminate your understeer.

[jlevie]

The car is understeering because; a) you don't have enough rear sway, and b) don't have enough front camber. With money being a strong consideration I think you'd get the most bang for the buck with a set of Bimmerworld 22/19mm sways and a set of GC Spec E30 camber plates. Then get the car corner weighted and fiddle with spring pads to improve cross and front/rear balance.

[djjerme]

Two things I am noticing right off the bat:

1) You have a lot of mod's already done on the car.
2) This is your first season.

What is your goal right now? Is it to win at Autocross or build a kick-arse E30? You have to decide which is your goal. If you want to win at Autocross, then take your combination you have and learn to drive the piss out of it. In fact, you may be better off to go back to stock on some of the mods if it will put you in a more competitive class. Learn to drive what you got, even if you feel it's got issues. I have seen good drivers take piles of crap and beat out several well sorted machines; in both AutoX and wheel to wheel.

You are collage student right? If you want to get better at say math, do you go buy top of the line graphing calculator, the best mechanical pencils and the highest quality, hand woven paper? No you study the hell out of math. Take that $300 and buy a good Autocross book (or rent one from the library). Then take the leftover and buy some Pizza and Beer. Then you take the pizza and beer and offer it to the guy with the fastest, consistent times at the event in exchange for some coaching and possibly even have him ride along on one your runs. Trust me, you will gain more than you ever would spending $300 on go faster bits.

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..

[jntar]

Wait, what? Larger front sway will stiffen the front end, and make understeer worse, not better. That said, the reduced body motion (especially in transitions/slaloms) may still result in the car being faster.

OP, your basically just looking at larger sways, or coil-overs. Generally speaking most people agree that stiff springs are a better way of controlling body motion than really large sway bars.

Oh and BTW, your body roll issues aren't that bad...


;)

Lol! So true! Stock former has so much roll. I wanted to originally run gstock, but my car came with the suspension already on it and I didn't want to go back to stock.