Suspension set up

Post Tue Feb 12, 2008 8:58 am

Advice wanted please!
I've done a few track days now in my 325 sport and am finding the car a little too soft. The car is stripped with cage and buckets etc and is road legal. I will be doing approx 2000 road miles a year and roughly 4 track days.

I did a bit of investigation last night into the existing set up, the car has uprated springs front and back which has lowered the car 60/40 (a stance I want to keep). I have no idea what the springs are other than them being red!

At the rear the car has bilstein shocks (are these standard on sports?).
The front shocks are black but have no marking to determine what they are ~(are these standard BMW?).

My main concern is the rear is too soft which results in an inbalance under hard throttle and when coming out of corners. The front appears to be much stiffer and passes my bump test (pushing down on the wing). I am aware that the back should be softer but I think the handling of my car can be improved.

I have about Ã‚£300 to spend on the car so what do people recommend, springs first? shocks? H&R Cup. If I do just springs I could also upgrade front discs.......

Post Tue Feb 12, 2008 9:17 am

I think first you need to decide what you want, looks or handling. Just my own opinion/experience here but I do not think 60/40 is good for handling. You need to get the reaR down.
Next thing is to find out if you have a mating set of shocks. I am afraid you will have to take the front strut inserts out to be sure. a clue for Bilsteins is the thick chrome rod (the bit sticking out of the black tube), if this is almost as thick as the black housing it's most likely a Bilstein.
Good springs can be bought for reasonable money at www.dfaulknersprings.co.uk and together with a set of Bilstein B8 dampers you have as much as you can get for your budget. Don't get tempted to buy a cheap coil over kit.

If you want something good value for money and decent, join the group buy for GAZ coilovers

Post Tue Feb 12, 2008 1:50 pm

Thanks UweM3, the car is as I bought it and I am more than happy to change it. I would always go for performance over looks. I will investigate the mating shocks, is taking the front stut inserts out easy?
If I go for upradted springs what drop would you recommend? Faulkner do 10mm, 35mm and 55mm.
Thanks

Post Tue Feb 12, 2008 4:26 pm

id have to say 55 all round i reckon...

u will get excessive rear camber but u can either live with this (tyre wear) or build some adjustabiity into ure rear beam by slotting it and using eccentric bolts

Post Tue Feb 12, 2008 4:30 pm

Karen, will the excessive camber have any other negative effect or is it purely tyre ware?

Post Tue Feb 12, 2008 4:42 pm

ScottEgg wrote:Karen, will the excessive camber have any other negative effect or is it purely tyre ware?

will reduce traction in straight line due to reduced contact patch but u will be fine as this doesnt affect the e30 much due to the way they squat under acceleration.

if you are into drifting etc then the increaed rear camber will mean that the car will snap more quickly into slides more abruptly and be slightly harder to control when in the slide. In a addition when you are transitioning from left to right or vice versa, there will be reduced feeling with increased camber (once again due to contact patch)

For normal grip track work i reckon you will be fine with a 55m drop on rear to be honest but i would recommend eventually getting something like this done:

http://store.nexternal.com/shared/Store ... oducts.asp

just my opinion on the matter...

Post Tue Feb 12, 2008 6:06 pm

this is what i have on mine fairly cheap DIY job and means i can adjust the ride height front and rear and buy springs of different lengths and rates.

Post Tue Feb 12, 2008 6:09 pm

Karan links to ireland engineering don't work because the shop system is gay.

Are you refering to the toe and camber kit?

Post Tue Feb 12, 2008 6:12 pm

yep

stoneys idea is prob best for trackwork

coilovers are really the only way i reckon

Post Tue Feb 12, 2008 10:29 pm

I've got a similar setup for sale just now

It can come with a Brembo 4 pot brake kit attached

It may be gone by the weekend though

Post Wed Feb 13, 2008 6:12 am

Karan wrote:yep

stoneys idea is prob best for trackwork

coilovers are really the only way i reckon

Why? BMW sells a Grp N suspension kit. Non adjustable with springs like stock. Works a treat. Approx 5 times stiffer than stock M3. Not the cheapest, I know.

Lowest is not always the best. Keep in mind, every mm lowered is lost suspension travel. The lower you go, the stiffer the spring need to be to compensate for that. Or the suspension will run on the bumpstops which isn't a good thing.

Post Wed Feb 13, 2008 6:15 am

stoneyV6 wrote:this is what i have on mine fairly cheap DIY job and means i can adjust the ride height front and rear and buy springs of different lengths and rates.

I had a conversion like this a while ago. I can see you have taken the right approach to fight corrosion

Mine seized after 3 month, had to cut the collar nut off in the end. What have you done to the rear if you don't mind me asking?
what spring rates did you go for in the end?

Post Wed Feb 13, 2008 10:22 am

I use H&R cup kit on my E30 - fixed rate and great value for money IMO.

Post Wed Feb 13, 2008 10:25 am

Why? BMW sells a Grp N suspension kit. Non adjustable with springs like stock. Works a treat. Approx 5 times stiffer than stock M3. Not the cheapest, I know.

Uwe, where can you purchase BMW Grp N stuff from?? Nobody seems to know the answer to this..

Post Wed Feb 13, 2008 12:09 pm

Thanks all. I would like to keep things as simple as possible to start with and could play with camber settigns in the future. Oldbimmer do you use your motor for track days? is the H&R Cup kit stiff enough?

I'm trying a simple approach and want to ensure that I have the same set up front and rear which i think is the best idea right? I have no idea what springs are on the car so I am keen to replace them with new regardless of any other mods.

Post Wed Feb 13, 2008 12:14 pm

oldbimmer wrote:
Why? BMW sells a Grp N suspension kit. Non adjustable with springs like stock. Works a treat. Approx 5 times stiffer than stock M3. Not the cheapest, I know.

Uwe, where can you purchase BMW Grp N stuff from?? Nobody seems to know the answer to this..

at your BMW dealer! Just give him the part numbers.
I have a Group N catalogue on my computer at home. Do you need it?

Post Wed Feb 13, 2008 12:27 pm

ScottEgg wrote:Thanks all. I would like to keep things as simple as possible to start with and could play with camber settigns in the future. Oldbimmer do you use your motor for track days? is the H&R Cup kit stiff enough?

I'm trying a simple approach and want to ensure that I have the same set up front and rear which i think is the best idea right? I have no idea what springs are on the car so I am keen to replace them with new regardless of any other mods.

....there is a H&R kit in the for sale section

Post Wed Feb 13, 2008 4:11 pm

ScottEgg wrote:Thanks all. I would like to keep things as simple as possible to start with and could play with camber settigns in the future. Oldbimmer do you use your motor for track days? is the H&R Cup kit stiff enough?

I'm trying a simple approach and want to ensure that I have the same set up front and rear which i think is the best idea right? I have no idea what springs are on the car so I am keen to replace them with new regardless of any other mods.

Yes, my car is only used for trackdays and I drive it to and from the track.
I have the H&R cup kit and a set of H&R anti-roll bars and I find it excellent on the track, it's certainly stiff enough for me (perhaps a little too stiff for the road, but I guess that's a matter of personal preference)

I also use the offset M3 control arm bushes and the BMW "camber correction" top mounts for a bit of extra negative camber. This coupled with Toyo R888 in 205/50/15 adds up to a very enjoyable and very capable track car. Many more expensive machines have been humbled by the budget E30!!!

I have just bought a set of adjustable top mounts from UweM3 - this should further improve things.

Anyway, to get back to the point - I can wholeheartedly recommend the H&R cup kit for trackday use. Lots of others on this forum also rate this kit highly. Yes, there are better soloutions out there but they are generally more expensive and let's face it, unless you REALLY know what you are doing, playing with spring rates and bump/rebound rates will probably be a source of constant frustration for you.

I like to keeep things simple!

Post Wed Feb 13, 2008 4:14 pm

at your BMW dealer! Just give him the part numbers.
I have a Group N catalogue on my computer at home. Do you need it?

Uwe, yes I would love to have a copy!!
I'll PM my details

Post Wed Feb 13, 2008 4:23 pm

UweM3 wrote:
Karan wrote:yep

stoneys idea is prob best for trackwork

coilovers are really the only way i reckon
Why? BMW sells a Grp N suspension kit. Non adjustable with springs like stock. Works a treat. Approx 5 times stiffer than stock M3. Not the cheapest, I know.

Lowest is not always the best. Keep in mind, every mm lowered is lost suspension travel. The lower you go, the stiffer the spring need to be to compensate for that. Or the suspension will run on the bumpstops which isn't a good thing.

true with the grp N stuff, but maybe cheaper in long run to play with coilovers-eg chop and change rates til ure happy etc as ive bought springs for coilovers and they're cheap as chips

Post Wed Feb 13, 2008 9:39 pm

Karan wrote: true with the grp N stuff, but maybe cheaper in long run to play with coilovers-eg chop and change rates til ure happy etc as ive bought springs for coilovers and they're cheap as chips

Deffo the right thing to do. But I think he is on a budget at the moment.
the time and money I have spent with "normal" springs would have bought me a nice set of coilovers in the first place!