Need Advice on Eliminating Body Roll *Tight Budget*

[freeride53]

Please post back with updates! This thread is extremely relevant to me.

[Emre]

I decided on the j-stock springs and GC camber plates.

Good choice.

[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)

[BlackbirdM3]

I decided on the j-stock springs and GC camber plates. It was the cheapest route for me since I can sell my H&R race springs and recoup some of the money. I'll post up my opinions and photos when I hit up the next autocross on the 6th and 7th.

I will bet the farm your suspension geometry is wrong assuming you got the Spec E30 adjustable camber and caster plates. The J-stock springs are crazy high spring rates, unless you got the correct dampers to go with them, the car is underdamped. I bet it will skip over every irregularity out there. It won't bottom, but it also won't absorb anything short of a large square edged impact either. A suspension system needs to move to work, and its got to work to get the car to stick.

It might be fine for an all out race car that can't run coilovers, but for anything driven on the street, or even a slightly rough track the thing is going to hop and skip around, it will feel very poorly planted. I've driven an E30 M3 with similar rate springs and the thing was the most nervous thing ever to the point of being hard to drive even on the street. Sure, it corners flat, but it also breaks into a drift far too early in a corner as well.

A little compliance in the suspension isn't a bad thing.

Will

[jntar]

I decided on the j-stock springs and GC camber plates. It was the cheapest route for me since I can sell my H&R race springs and recoup some of the money. I'll post up my opinions and photos when I hit up the next autocross on the 6th and 7th.

[brent5631]

OK. I have seen those. But they only work on e30 M3 suspension. You would need something like this for the regular e30 suspension.

http://store.bimmerworld.com/e36-race-front-control-arms-p1021.aspx

And if you have coils there is no need for the spacer above the camber plate. Just spin the adjusters up and get more suspension travel to boot.

[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

[Berkut]

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

[brent5631]

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

[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

[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!

[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.

[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..

[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.

[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).