Track car suspension setup advice

Post Tue Oct 13, 2009 8:41 pm

Hi there,

Got back from my first full day in my E30 slag at Brands Hatch yesterday. We had to cut the day short because the NSF tyre was down to canvas and blistering on the outside.

The car is a stripped touring and has spax psx adjustable shocks with 60/40 springs. The tyres are 2nd hand R888s.

The dampers were set to 20/24 front, 16/24 rear. This minimised body roll and made the car stable and predictable (and a lot of fun!), however i suspect all the forces were transfered to the tyres, which rolled over onto the wall, hence the tyre under the most stress overheated and wore out.

So, getting to the point... Will the maximum negative camber i can have without coilovers (2 degrees ish IIRC) be enough to give me even tyre wear?

Or any other thoughts/sugestions welcome.

Thanks

Post Tue Oct 13, 2009 8:44 pm

Probably not enough with 888's most of the pbmw racers are running 4-5 degrees neg camber on coilovers if i remember correctly, however every little helps.

Post Tue Oct 13, 2009 9:09 pm

It will at least help.. You should be able to get just over 2deg with normal springs i reckon

Post Tue Oct 13, 2009 9:15 pm

why does it matter about standard springs ?

Post Tue Oct 13, 2009 9:19 pm

The standard diameter spring hits on the inside of the suspension turret, needs a coilover spring for more neg.

Post Tue Oct 13, 2009 9:30 pm

Toyo recommend 4-5 degrees on an e30

What pressures were you running?

Post Tue Oct 13, 2009 9:38 pm

The standard diameter spring hits on the inside of the suspension turret, needs a coilover spring for more neg.

where are you adjusting the camber ? at the top mount ?

Post Tue Oct 13, 2009 9:40 pm

Where else might you adjust it?!

Post Tue Oct 13, 2009 9:41 pm

adjustable lower arms

Post Tue Oct 13, 2009 9:48 pm

Yep on the topmounts

Post Tue Oct 13, 2009 10:30 pm

Tyre pressures were 26 cold. Hot pressures were 32-34, 34 being the NSF.

Anyone know how much eccentric bushes give you on top of 2 (ish) degrees with top mounts? Or any other tricks to gain more?

You can "shim" E36 struts with washers, don't suppose that's possible on E30s?

Post Tue Oct 13, 2009 10:42 pm

bastosm3 wrote:adjustable lower arms

Eh?

Group A setup?

Post Wed Oct 14, 2009 2:23 am

Wocka wrote:Tyre pressures were 26 cold. Hot pressures were 32-34, 34 being the NSF.

Anyone know how much eccentric bushes give you on top of 2 (ish) degrees with top mounts? Or any other tricks to gain more?

You can "shim" E36 struts with washers, don't suppose that's possible on E30s?

If you mean the control arm bushes, you don't get any more static camber, just more castor. You do get more dynamic camber as a result of this.
An E30 strut contains the front wheel bearing housing; it's not on a seperate hub assembly that's bolted on, so the only place you can add camber is at the top mounts.

bastosm3 wrote:adjustable lower arms

Steady on, old chap! The poor lad hasn't even built coilovers yet

Post Wed Oct 14, 2009 7:35 pm

wouldn't take much to make. a small amount of welding, the cost of some rose joints and a stainless pin making up on a lathe. Although i worked with a group A M3 at work, i never actually looked at the arms to see how they were done. I do remember the trick way in which ride height was altered though

The Strut was adjusted through the top mount, with normal coil overs as you lower ride height, travel is also shortened, but in the case of the group A cars the travel was always the same and only ride was altered.

Post Mon Oct 26, 2009 2:29 pm

regardless of what you do to your setup, Brands Indy will eat your Left front tyre. Just a matter of time. And R888 are too soft IMHO for the E30 anyway.
60/40 springs won't help either, get the back lower or the front higher to unload the front a little.
And 34 hot is too low IMO, I run them 40 hot.

Post Mon Oct 26, 2009 2:58 pm

Very interesting, i have done few track days at Brands on R888's and they seem to last reasonably well but yes, front left definatly goes first. I was wondering/hoping that puting a negative camber with those plates might help, to be fair it may make it worse.

How are you getting on with them Uwe? surely 40 hot is too much?

Post Mon Oct 26, 2009 4:39 pm

i run a lot a brands on both slicks and 888's. i run 4 degree camber on 888's at about 32 hot, but if your doing a full day of about 120 to 140 laps just swap front to back at lunch time.Because whatever you do paddock hill will eat your tyres.

Post Sat Nov 07, 2009 1:44 pm

Why doesnt anyone dial in abit of castor, and always go for big negative camber?

Post Sat Nov 07, 2009 2:35 pm

driftmonkey wrote:Why doesnt anyone dial in abit of castor, and always go for big negative camber?

I'm not so sure how castor would help as it would have to be quite excessive to add enough dynamic camber imo, the advantage of adding static camber is so that when the sidewall of the tyre deforms it rolls onto the flat of the tread, not onto the beginning of the sidewall like it would with lower degrees of castor and small steering angles.

Here is a pic of mine with approx -2 degrees of camber, you can see why the adding more front camber would help with the tyre wear on the edge of the drivers side tyre and help increase the contact patch when using a small steering angle. For the amount of lock I have on adding static camber is going to have a much more positive effect than adding dynamic camber by adding castor

Post Sat Nov 07, 2009 6:02 pm

mattrs wrote:
How are you getting on with them Uwe? surely 40 hot is too much?

give I try. You may like it. I do.
IMHO running the Toyo's too low will just increase the side flex and the R888 overheats quicker. I feel I can get three or four laps more out before they "go off".
I do not rate them high for the e30 anyway, there are more suitable tyres.

Post Sun Nov 08, 2009 1:57 pm

UweM3 wrote:
mattrs wrote:
How are you getting on with them Uwe? surely 40 hot is too much?
give I try. You may like it. I do.
IMHO running the Toyo's too low will just increase the side flex and the R888 overheats quicker. I feel I can get three or four laps more out before they "go off".
I do not rate them high for the e30 anyway, there are more suitable tyres.

Which are more suitable? For track use? Also how are you getting on with the camber plates?

Post Sun Nov 08, 2009 5:23 pm

mattrs wrote:
UweM3 wrote:
mattrs wrote:
How are you getting on with them Uwe? surely 40 hot is too much?
give I try. You may like it. I do.
IMHO running the Toyo's too low will just increase the side flex and the R888 overheats quicker. I feel I can get three or four laps more out before they "go off".
I do not rate them high for the e30 anyway, there are more suitable tyres.
Which are more suitable? For track use? Also how are you getting on with the camber plates?

Yokohama, Dunlop.
What do you mean with getting on with camber plates? Making some? Looking really bad at the moment, no spare time.

Post Sun Nov 08, 2009 9:14 pm

Yes making them, I had hoped for; there ready and yours for blah blah, never mind mate I know how it is to have next to no time, it sucks!

40 hot, surely that would make for a smaller contact with the road? I am going to try it, but it’s contrary to a lot of advice from others though.

Post Mon Nov 09, 2009 9:57 am

Toyo recommend 30psi hot on the R888

On a PBM car thats achieved by starting somewhere between 21-24 dependant on circuit and conditions.