Need Advice on Eliminating Body Roll *Tight Budget*

[jntar]

Just a quick update.

What I did end up going with.

1)Kmac camber plates (this virtually eliminated my understeering problem completely)
2)Whiteline 24mm front bar (fixed the front roll and also seemed to help keep the camber in the front while hard turn in)
3)BFGoodrich Rival 205/50/15 tires (HUGE step up from the Yokohamas I had on there)


Hello need some advice from the autocross guys. I own a '91 318is and run STX class in SCCA. This is my first season and I wanted to get some opinions on dialing out some suspension issues that I have already came across in my first race of the season.

Car
'91 318is
m42b18 w/mark d 93 oct chip
H&R Race springs
Bilstein sport shocks/struts
Stock tophats (non adjustable camber)
21mm front sway bar/stock rear bar
All poly bushings and upgraded rear shock mounts
'96-'99 e36 steering rack 3.2 turn LTL
Kosei K1 15x7
Yokohoma AVS ES100 225/50/15
4.10 LSD

Issues
1)Car requires a large amount of steering input to maintain line at cornering speeds. At times grip immediately runs out and the car will understeer until brakes are tapped or wheel is quickly adjusted. This is causing me to lose a few seconds over the course.

2)Body roll. It's pretty bad. Pics below.

Budget
I'm a broke/poor college student. All my money right now is going to living expenses, car maintenance, and parts for a turbo kit I'm piecing together (long ways away).

Budget
~$300

Options
1)Ive read about the J-springs and have a friend who would buy my H&R springs which would offset my costs. (possibly enough for fixed camber plates)

2)Upgrade to 25mm front swaybar and possibly upgrade the rear bar as well.

3)Other ideas?


Thanks for the help!

[e30_3I8I]

Front sways will stiffen the front to help with your front end grip.... I have a rear strut bar that helps me out a lot that's all i have on my car.. I don't auto-x but my car can carve through the canyons well for its basket weave tire size.. I know if i get bigger and wider tires it will help out tremendously.

[ak-]

Purchase GC kit with higher rates, do the install yourself, sell Race springs as compensation and stay under 300.

[Nsquared97]

Front sways will stiffen the front to help with your front end grip.... I have a rear strut bar that helps me out a lot that's all i have on my car.. I don't auto-x but my car can carve through the canyons well for its basket weave tire size.. I know if i get bigger and wider tires it will help out tremendously.

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...


;)

[!kid]

Front sways will stiffen the front to help with your front end grip.... I have a rear strut bar that helps me out a lot that's all i have on my car.. I don't auto-x but my car can carve through the canyons well for its basket weave tire size.. I know if i get bigger and wider tires it will help out tremendously.

A larger front swaybar will increase turn in response but will not increase grip. back when I was into fwd cars I would actually find smaller front sway bars to reduce understeer and increasing my front end grip. Generally sway bars are used to tune oversteer/understeer. so a larger front sway bar is going to increase his understeer.


OP,of your 3 options I would suggest the J stock springs.

[pandaboo911]

Higher spring rates = less body roll

[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.

[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..

[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.

[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.

[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]

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:

[ak-]

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

[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-]

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!