E30 Zone

I'm getting piles of understeer on track. Car's a 325i Sport, 1990; Bilstein Sprintline suspension, standard wheels, Colway Formula Intermediate race tyres. Been doing tracks for 20 years, so I've done all the usual stuff with tyre pressures (down at the front, up at the back) - it's obviously a geometry thing. I need to introduce some negative camber. How much camber, what bits do I need and who do I get the bits from?

what has changed since you didn't have understeer
that may help
not neccesarilly camber as some tracks don't necessarily need to have it on.
just think of your wheel angle to the track. if it has all the tyre still flush with any suspension bits movin its definitely not camber.
the best way of checking for this is if you can get someone to take a picture of your front wheels at the time of understeer . take a close look

I've only had the car for a couple of months. First trackday was with standard everything. Sideways everywhere, no understeer at all. It's now got massively more mechanical grip, which means that fundamental design traits come in to play - i.e., built-in understeer at the limit.

It's defo a camber thing, just need to know where to get the bits, and how much camber to whack on it.

Pix here of the BMW: http://www.trackphoto.co.uk/car.php?DIR ... TVH&PAGE=1

Pix here showing victims roung Oulton in something a bit nippier: http://www.trackphoto.co.uk/car.php?DIR ... OOL&PAGE=1

nice motor have you stripped it out
half way through doin mine
if you want to adjust camber try speaking to the kumho bmw championship forum they'll put you right
let us know how you get on
what times did you get at oulton,
i got 1.41 at donnington with a damp track last year, off to brands in 12 days , hopin to get under 1 .00 for the indy would be nice. get 0.52 in my single seater no prob, different animal though
good luck

The plan is to leave it as standard looking as possible. As I help run a trackday company, I'm not allowed to do timed laps.

ok m8, you don't have timing equipment i know but if you have a passenger he can tell you using mobile phone hey.
which trackday company is it and what part do you play
whats the rules for camcorders, and what is securely fitted, does masking tape come into it or do you need a proper pod

Easytrack. www.easytrack.co.uk . Camcorders have to be bolted in.

Easytrack. www.easytrack.co.uk . Camcorders have to be bolted in.

cool
can you get us any discount , blag blag grovel , gotta try hey
they go to spa silverstone brands , all over . look good

Sorree, they're usually sold out. Best bet is book early, because the prices go up closer to the date.

yes i can see
got the 2 brands hatch evenings booked a long time back (22-6)(25-7)
the mallory beginnin november looks like a possibility as well
excellent value

Enjoy it, but don't let us catch you timing or with anything loose in the car - it invalidates our insurance. We run a tighter ship than most....

no problem m8
thanks for the advice
certainly don't want to bend my car thats a fact, and usually alone but if a m8 comes along who fancies a passenger ride we're pretty careful you know.
never overtake on bends or until the guy in front indicates you to pass, see some people who wizz by at dangerous places without any cares
yes we pretty well behaved in comparison i'd say
have you had any incidents with dangerous people and throwin em out

Is the understeer on turn in, power out, or both?

I have just got front strut top plates that adjust for camber (from K-Mac). I haven't been back to the track yet but they do feel like the reduce the understeer powering out of a corner. I mean under hard acceleration it holds its line better and understeers a little bit less. Not a big difference but it is noticable.

Sounds like you know what you are doing but if it oversteered at first and then you changed the suspension and it understeered maybe you should try making some changes to the suspension again to make it a bit more neutral?

My 323i has lower stiffer springs and Koni sports dampers all round as well as M3 offset front control arm bushes. I have an LSD too which usually increases understeer a little bit. My car doesn't understeer that much though, sometimes just a little bit turning in but mostly it is neutral.

Tables like this one (there are many but this is the only one I could find quickly) http://www.tirerack.com/tires/tiretech/ ... ?techid=58 say to increase front tyre pressure and decrease rear tyre pressure to reduce understeer. Depends what tyre pressures you started with though, I know sometimes I have reduced my front tyre pressures and that decreased understeer.

Aston

Done the tyre pressure thing, made a bit of difference eventually. Oh, and it's the other way round: lower the front pressures to reduce understeer while increasing the rears - higher pressures means harder tyres, means less heat, means less grip.

Ultimate grip on the Colway tyres is pretty good, which probably exacerbates the situation, particularly at the back with the LSD. The circuit speeds are too high (and car not powerful enough) for power-on oversteer. The only way I can get it sideways is by violent lift-off into a corner

No matter how I drive it, there's understeer, even with a massively "slow-in, fast-out" approach.

I think it may be a combination of a need for stiffer anti-roll at the rear, and a touch of negative camber at the front.

Took me 18 months to get my Lotus exactly as I wanted it, with a combination of tyre pressures and geometry front and rear considerably different from the factory settings, but then again - despite it being a Lotus - just like most other cars it was designed to understeer when really pushed, primarily to stop Americans sueing them if they went backwards through a Californian vineyard hedge.

What I meant about the tyres is that all the tables like that http://www.tirerack.com/tires/tiretech/ ... ?techid=58 I have seen on the internet say higher front pressures and lower rear pressures to reduce understeer. I would normally think of it the other way around too, I was just telling you what I found. That table is also from the Tire Rack who are supposed to know what they are talking about. Like you said though, I usually do it the other way around.

I have even less power with my 323i and I have what should be a slightly gripier LSD than the factory one (rebuilt from motorsport parts). I also have ok tyres, maybe not quite what you have but they are a racetrack type tyre. I definately can't get any wheelspin on dry bitumen when moving and I would struggle to get much even from a standing start (without destroying my drivetrain anyway). It still seems very neutral to me though. Through the higher speed corners (80mph+) under full throttle the back feels like it is just starting towards oversteer, it never does but it doesn't understeer either. I can get understeer by going into a corner too quickly but most cars will understeer if you do that, they all have limits. Also a lot of corners I can accelerate out of with full throttle from the apex without much or any understeer.

So with just lower stiffer springs, Koni's, and M3 offset control arm bushes (I haven't tried the camber adjustments on a track yet) my 323i feels ok. That is why I thought that maybe it was something to do with the suspension setup? But then Bilstein should know what they are doing and I imagine you do too so I don't really know.

If you want even more camber than the strut top adjusters can give then I think people bend the strut towers in, kind of serious modification though.

Aston

Ah, yep, see what you mean re the pressures.

Pressures depend on track / air temp & every tyre has a different 'best' operating psi & it's not strictly true that dropping the pressures offers more grip, if it's too cold they won't warm up enough & if it's too hot they'll overheat. It's a complicated science that not many people (including me) understand fully

The E30's do have alot of understeer & the camber needs to be adjusted in line with ride height, have you adjusted the toe at all? if not give it a try before adding lots of - camber. Also, are the front shocks adjustable? If not then i would strongly recommend changing them to adjustable & softening off the front's a bit & hardening the back & then try again. Moseley Motorsport sell adjustable camber/caster bushes for the rear & top mounts for the front's www.moseleymotorsport.com.

^ What he said about the tyre pressures. Something you have to try and see what happens, which it sounds like you did (the 20 years experience probably helped too ).

Sounds like my car is a bit wrong, I have the rear shocks at there softest setting and the fronts at about medium (how many turns do the Koni's have? I am using about 2 turns on the front). But it seems to work, and to change the rear shocks I have to take them out, so I'll leave it for the moment.

I still don't know why my E30 would seem fairly neutral when they are supposed to understeer. I actually thought they were supposed to oversteer? I thought the E21 was known for it's tail happyness and the E30 was just a bit more refined, but still willing to slide about if provoked?

Aston

All things considered re weather/conditions and temperature, of course.

Taffy - given I'm probably going to go for -2 camber, any thoughts on what toe geo?

Aston: car behaviour is massively different on track compared to road - powersliding round a tight corner or roundabout can often be more about loads of low-gear power and torque overcoming cold road tyres on a poor surface.

I think there's probably fewer than ten corners on all the UK's circuits combined where second gear is essential (hairpins at Anglesey, Mallory and Rockingham, bits of Bedford, maybe Silverstone complex...), with most road cars using only third and fourth for an entire day's driving.

That means your minimum track speed can actually be, on occasion, the maximum speed you might achieve in normal road driving.

Try breaking traction in first or second on the road - pretty easy; Try breaking traction in third or fourth - virtually impossible. The rear of a (set up for the road) car is that much more stable when it has only lateral forces to cope with instead of both lateral and longitudinal forces, so as speed gathers (and through high speed corners where torque can't break traction) the rear is doing half the job it was designed for, the front is doing twice what it was designed for (direction and grip).

At low speed, basically the power to the rear overcomes the grip at the rear before the grip at the front is challenged.

Having said all that, a car, of course can be like a set of clothes. What suits one person won't suit another - Schumi likes a pointy car that'll kick sideways, Alonso's car is set up with understeer, Ralf's is set up to turn left and T-bone anybody that gets anywhere near him ...

about Ralf.

I don't understand exactly what you are saying though, I use my car on the road and on the track (both bitumen and dirt). Probably a total of 20+ races and track days in the last year and a bit. I have been to a few tracks with different corners, some 2nd gear lower speed, some 4th gear higher speed, and some in between.

You can break traction in 1st and 2nd on dry bitumen!? I could in 1st if I used a lot of revs and destroyed my drivetrain, definately not easy, and probably not at all in 2nd (well maybe a little if I give it heaps exiting tight roundabout with gravel on the inside or something, not that I've tried ).

Oh and I wish I could powerslide around roundabouts but unfortunately my driving sucks .

I think my car must have about 2 degrees negative camber now, I haven't spoken to the guy who set it up yet but it is at the max of the adjustment plates. Not sure what the toe is either, as soon as I finish my exams I am going to see him.

Aston

Breaking traction on the road - sorry, to clarify, conditions where the car or road allow it: T junctions, roundabouts, tight bends, poor surface, no traffic, lots of provocation...

... the point being it's an entirely different set of dynamics at track speed over road speed.

Oh, okay.

I thought we were only talking about on a race track, sorry I got confused.

Aston

I do it all the time - get confused that is.

you might find these useful:

https://secure1.nexternal.com/shared/St ... =526679635

Damn, link doesn't work directly to page, bloody frames; so click on Suspension & Steering, then click on Misc Performance Components then on E30/E28/E24 Fixed Camber plates.
Looks like they also have some adjustable plates.

I've got these on my Milltek BMW race car. I get almost exactly -2Ԛ° camber with these on my suspension. Cheap and easy to fit.
hth,

Toe out / Toe in depends on track, more toe out = better turn in but Less stability so for instance you wouldn't want loads of toe out at Thruxton where it's 5th gear for 80% of the time, or conversely you wouldn't want loads of toe in at somewhere short & twisty like Croix

Another thing to consider would be the M3 style eccentric bushes which would mean you keep more front tyre in contact with the road at turn-in so reduce understeer I believe.

Powerflex do them:-

http://www.powerflex.co.uk/products.asp ... ubmit1.y=9

What toe out does anybody use?

Depends on track, last year we went from 30min out to 5 mins in

I prefer Oulton, Anglesey, Brands, Rockingham. Occasionally Silverstone and Combe. Prefer good turn in and slightly slippy back end. Hate understeer.

^ That's how I feel. Unfortunately, as you probably know, the fastest setup is usually one that is mostly neutral but has just a little bit of understeer. Less fun, so not what I'd do for my track day car, but what would be best in a race car.

Aston

It's all down to preference, personally i prefer a softer set up than most

my sport corners fairly neutral particularly on trailing and on the throttle...

try offset top mounts on the front (from dealer) and offset m3 tca bushes

ure steering will go light in the centre but will feel great when loaded up!

a stiffer rear arb will also help a lot.... renew droplinks and all suspoension bushes also with poly items and ure e30 will go round the outside of imprezas....

-3degrees to -5 degs of camber at front and couple millimeters of toe-out at front. We run -5degs and 3mm toe out and car is really good at turn in.

-5, bloody hell!