Just out of curiosity... what do you think this base suspension setup will do like?

[SA E30]

Ok, so here is a question just out of my own curiosity about the setup on my e30 race car that will be done in a month or so.

The car comes in at aroudn 1100kg, is powered by a s54 running standalone.

The tyre setup is 235/630/17 and 260/630/17 Slicks

My suspension is as follows.

E36 328i Sachs Group N struts 900lbs front springs, Camber plates, Tubular Arms, Adjustable H&R bar, 1.4 inch roll centre spacers, 0.8 bump steer spacers. The inner Control arm pick up is raised 7mm from stock, and the inner rack end pickup is 4mm up from stock.

Currently running 3.6 camber up front, 19 caster, front ride height 90mm lower than stock

Rear are custom made adjustable coilover dampers running 650lbs springs, the car has raised rear subframe (1.2cm) camber and toe adjusters, and no rear sway bar.

Running 2deg camber, and 4mm toe in, rear ride height 75mm lower than stock


So what handling characteristics do you guys think the car will have on this baseline setup?

[Wh33lhop]

Good ones. :p It will be stiff as a board, not sure how much the front sway bar is going to help.

I'm not so sure how the roll center and bump spacers are going to affect your geometry as I'm not sure what's ideal.

Go drive it.

[SkinnyVT]

what's the weight distribution? I am going to guess that eventually you will be putting a little more tire up front, how much power do you expect to be putting to the ground?

[gobuffs]

I think you are too stiff on the rear springs. I was running 800 fronts and 400 rears and it was ok. I now have 800 all around and it is also ok

[Wh33lhop]

I think you are too stiff on the rear springs. I was running 800 fronts and 400 rears and it was ok. I now have 800 all around and it is also ok

...what?

[JGood]

I'm curious how that stagger will work out for you. Any reason you don't go with a square setup off the bat and tune from there? Or are you basing this build off someone else's car that had good results?

[SA E30]

No just basing the build on tyres I could get at the time (which I can now get 290's for the rear, and 260's could go up front) but the fenders aren't built to take these tyres.

I will be rebuilding them in the future as they are all metal right now and I would prefer them lighter and wider most importantly better looking as they not the prettiest at this point in time.

@Gobuffs if you said that 400lbs was ok, and 800lbs is also just ok. Then it seems like the middle ground might be just right?

P.S. Your race car is beautiful!

@JGood seeing as that this side of the world we don't really have any "hardcore" e30's. I looked at that many of the BMWCCA Mod guys were running on their e30's and they all seemed to be running quite a bit stagger.

@SkinnyVT Well the stock motor makes around 340hp to the fly, and we are running standalone, headers and a side exit exhaust. So say around 360hp on the fly. This is just for starters I would prefer to get more tyre on the ground and get to grips with this car before adding much more power.

I'm not sure on the weight distribution, we all know it will have a front bias, but I've done as much as I can to try solve that. Carbon hood, pin on fibreglass front bumper and valance, skinned doors. 42lt fuel cell is in the trunk, with diff cooler and pump.

My seating position has also been moved back almost to where the back seat hump is (I'm a short 5.9). Pedals are still in the stock position but the seat and wheel are moved back and down. It's actually quite a nice change from my old e30 which I had to sit right up close to the wheel for the correct seating position, my legs always felt cramped up and too close to the pedals.

[Teaguer]

I think what gobuffs is saying is that since you are running true coil-overs the rates may be too stiff.
The same 650lb rates on the stock spring location would have less effect than in your current location on the shocks.

[SA E30]

My 1st source of information for suspension setup was from the DTM cars, and then of course going over loads of threads but most importantly from one of the top suspension guys here.

He also had his doubts about running a 650lbs rear spring, he suggested 600lbs. I do have 600, and 700lbs rear springs as well as 800, 950 and 1000lbs front springs (he suggested 1000lbs up front).

So I do have a base to play around with if the car is sprung to hard.

At the current ride height the car has 2.5 inches of compression travel on the front dampers before I hit the chassis leg (which has been cut and welded a bit).

So yeah, that might need to come up a little on the ride height but I will see if I hit the legs 1st, as our tracks are pretty smooth here.

[gobuffs]

Sorry I was unclear. I ran 400s in a coilover location and now have 800s on the stock location. I no longer run true coilovers in the rear. I had 800 front 1050 rears last event and that was too stiff. I borrowed some 900s and they worked well. I traded my 1050s for 800s. Other than wheel diameter and width, my setup is similar to yours.

Again, sorry for being unclear in my first post.

[SkinnyVT]

OP, the ratio of front to rear spring rates is fairly close to what I am running. I think you will be ok depending on what your weights end up being. It may take some tuning in order to make those tire widths work. Are you running any front sway bar?

[SA E30]

Ahh, ok. Thanks for the clarification gobuffs. I saw your build on Bimmerforums I can't say I remember you are running 18's but I can't remember what your rim and tyre widths are?

@SkinnyVT I'm running an H&R Adjustable bar but it was more of a I want to get the car done now buy. I was planning on running a DTM style solid bar. I'm not all that convinced that running that setup front and rear will be the greatest for traction, but then I'm sure the BMW Motorsport guys knew more about this than I do.

[SA E30]

A quick teaser of the car ATM.

[Jean]

SA E30 - more pics NOW! :)

[gobuffs]

I am running 18x10 ET 25 rims all around. I am expecting some 285/650 slicks to come in any day (just in time for Barber next weekend).