Help with current setup.

[Greg111 13]

Thought i may as well take advantage of this service to ask Josh a question.

The Taupo day just been the M3 was excellent on the track, had no oversteer probs at all except for when the tyres were cold which is understandable but had a tad bit of understeer which i resolved with more steering (as you do).

My question to you is, how can i eliminate this with out having a butterfly effect on everything else.

The current setup in the front is:

Bilstein adjustable ride height shocks.

Stupidly stiff Tein springs 800-900 pound (Competition use from what I'm told).

E36 factory modified bottom arms.

Enlarged Eibach Swaybar with solid bushes.

Alpina strut bar, can't imagine this does much other than stop my strut towers cracking further.

Underbody cross bar.

All new bushes etc.

New swaybar links as this car is a link killer.

Won't list the rear as the list will be twice as big, is there anything i can change, modify, replace etc that will cure a little of the understeer?

The car has also been seam welded some time in its life too.

Cheers.

Edit: Race slicks may be on the cards as well which I'm sure will improve.

Edited September 28, 2011 by Greg.

[tarrbaby 0]

what wheel alignment specs are you running? playing with some more front camber and toe will net you less understeer

[Greg111 13]

what wheel alignment specs are you running? playing with some more front camber and toe will net you less understeer

Not sure what specs they are, don't have the sheet with me.

More negative camber? Toe in, out?

[thorburn 121]

If you fancy a bit of reading

http://www.motoiq.com/tech/the_ultimate_gu...n_handling.aspx

[hybrid 1044]

Slightly more camber and toe out to match will help however will increase tire wear. If you use the car quite a bit on the road its not advisible as it will cause premature wear on your road tires.

That spring rate is very hard for road tires and will be heating them up pretty quickly on the track and as you know road tire over heat quickly on the track.

As you said you're going to try slicks.. maybe give them a go on your current setup before playing around. I did notice your car was running quite low, im not sure where is good around where you are, but finding a good alignment place and get the car setup for your ride height (dialing back some of the camber). I use Justin @ Tiretech on the shore here in AKL, others have their favourites.

Front camber caused by lowering the car will cause understeer unless toe out is dailed in to counter it.

If your shocks are adjustible it is possible to have them turned up too much or too little. Its one of the holy grails matching compression and rebound to your spring rate vs your cars corner weights. Something im still learning a lot about still on my own setup.

Some things to start with anyways.. hope that helped.

ooo also just a note: What works on a smooth track doesnt always work on the road as well. EG too much spring rate can be terrible on a b-road with lots of dips and camber chanes from corner to corner .. it can make the car very twitchy as you 'spring out' from one corner to another.

I run a linear spring (not progressive) while its predictable it can be a little bit too much on bumpy roads and unsettle the car..

[hybrid 1044]

A small video which shows some good differences in having reduced shock stroke length

[Greg111 13]

Slightly more camber and toe out to match will help however will increase tire wear. If you use the car quite a bit on the road its not advisible as it will cause premature wear on your road tires.

That spring rate is very hard for road tires and will be heating them up pretty quickly on the track and as you know road tire over heat quickly on the track.

As you said you're going to try slicks.. maybe give them a go on your current setup before playing around. I did notice your car was running quite low, im not sure where is good around where you are, but finding a good alignment place and get the car setup for your ride height (dialing back some of the camber). I use Justin @ Tiretech on the shore here in AKL, others have their favourites.

Front camber caused by lowering the car will cause understeer unless toe out is dailed in to counter it.

If your shocks are adjustible it is possible to have them turned up too much or too little. Its one of the holy grails matching compression and rebound to your spring rate vs your cars corner weights. Something im still learning a lot about still on my own setup.

Some things to start with anyways.. hope that helped.

ooo also just a note: What works on a smooth track doesnt always work on the road as well. EG too much spring rate can be terrible on a b-road with lots of dips and camber chanes from corner to corner .. it can make the car very twitchy as you 'spring out' from one corner to another.

I run a linear spring (not progressive) while its predictable it can be a little bit too much on bumpy roads and unsettle the car..

More Camber and toe could work, the car doesn't get used a hell of a lot really, sits in the garage for most of its life so not too worried about the tyres.

Yeah the tyres were getting really hot quite quickly and towards the end of the stints starting to over heat.

Slicks might be a go for the next round i think, the wheel alignment was done quite recently at the height it's at now so should be set up for that height.

Damper isn't adjustable on these shocks so the Teins are it, it is very harsh on the road, i tried to use it for a daily a little while back and thought f**k that after one day! (HawkesBay roads)

I forgot to mention, the swaybars are also adjustable, they're on the soft setting at the moment (links on the outer hole), don't know what this will do to turning if moved to the inner setting?

Cheers Josh and others for the input, always good to learn new things, haven't really been a suspension person, just know this car has had an extensive amount of money spent on this setup.

Edited September 28, 2011 by Greg.

[thorburn 121]

If you stiffen up the front sway bar you'll get more understeer.

Stiff rear gives you more oversteer

[Greg111 13]

Ok so if i stiffen the rear will that help turn the front as the rear is pretty stable at the moment.

[thorburn 121]

If your bottoming out your front shocks like what hybrid is hinting to, then stiffening the rear swaybar isn't going to fix the understeer problem.

With the added force going to the front outside wheel the understeer might be even worse

I'd test as shown in the cusco video. Might be a little more time consuming if you've got inverted shocks

[Greg111 13]

The shocks aren't bottoming out, the springs are that stiff there is hardly any shock movement at all.

[zl2cq 1]

The shocks aren't bottoming out, the springs are that stiff there is hardly any shock movement at all.

Has the car been a track car last year and this year - its looks identical model/colour to what pedalled very quickly at Taupo & Hampton.

I spent a bit on my E36, only to find that the spring / strut, shock package was totally incompatable with each other.

Now after monitored progressive changes it is perfect for road/track use.

Looking at its limitations and what could be done all started by speaking with Mike at Mosen Euro Parts, each small change bought about a positive result.

Paul - E36

[DRTDVL 0]

Something like this: http://www.ground-control-store.com/produc...p/II=700/CA=184

Might help, adding more caster will allow you to run less static camber but will give you the same mid-corner camber.

Info here about caster... http://www.motoiq.com/magazine_articles/id...-and-scrub.aspx

Where were you getting the understeer?

Edited December 9, 2011 by DRTDVL

[Greg111 13]

Has the car been a track car last year and this year - its looks identical model/colour to what pedalled very quickly at Taupo & Hampton.

I spent a bit on my E36, only to find that the spring / strut, shock package was totally incompatable with each other.

Now after monitored progressive changes it is perfect for road/track use.

Looking at its limitations and what could be done all started by speaking with Mike at Mosen Euro Parts, each small change bought about a positive result.

Paul - E36

Prob not the car you are thinking of, it was at Taupo a few months back but never been to Hampton. The car handles superbly except for the minor understeer, even though is is several different brands all mated together they seem to work well.

Something like this: http://www.ground-control-store.com/produc...p/II=700/CA=184

Might help, adding more caster will allow you to run less static camber but will give you the same mid-corner camber.

Info here about caster... http://www.motoiq.com/magazine_articles/id...-and-scrub.aspx

Where were you getting the understeer?

Cheers for that Heath.

Mainly just at the end of the home straight at Taupo, tends to sledge into the left hander, all the others seem to be fine, i think if i go semi slicks for next time that will make a huge difference, can only try.

Edited December 10, 2011 by Greg.

[DRTDVL 0]

Semi's will help a bit as you won't be rolling the sidewalls as much. What tyre pressures where you running cold / when you came off the track?

I was playing with the 205's pressures at hamptons and had massive issues with sidewall roll in the rear because the pressure was too low, which was causing a lot of float/oversteer on corner exit. And the pressures in the front where too low also causing roll/float and understeer on entry to the corners. We where getting a fairly even heat across the tyre just there was way too much roll/float in the sidewalls.

You could try something like this - http://www.tcmotorsports.net/blog/index.ph...s-at-the-track/

We did something like this when i took the 306 to taupo and found we where running onto the top of the B of the Bridgestone on the sidewall...

You could try an old cheap bastards method for semi's - Get some snow and mud tyres shave off most of the tread and you have a very stiff side-walled tyre that has a soft compound rubber

[Greg111 13]

I was running 30psi cold, i found that if i ran any more it had a worse effect with more understeer, my tyres ar 40 profile so not a lot of roll would happen to the side walls i would have thought?

If i can find a set of half used semi slicks it wouldn't hurt to chuck them on.