Understeer

[wardy18 33 1 Cars]

I find on our local hillclimb that in a very long right hander im getting alot of understeer and am jus tryin to think how to gain more grip to get me round! i did find lowering the temperatures to approx 22 psi all round gave me a great deal of grip an especially stop the rear end tryin to step out! Im thinkin i may try removing either the upper or lower strut braces to loosen up the front end slightly as with the upper strut brace an the lower omp sub frame brace fitted the front end must be very stiff an unable to flex to the corner at all? What do you think? Im also runnin about 2.3deg of camber, may try a little more or less, also what do you think?

[welshpug 1,657]

what torsion and Anti roll bars are you running? and do they match the front springs?

[wardy18 33 1 Cars]

To be honest with you, i really dont know the answer to any of those, i really could do with finding out the spring pressure or whatever it is an yeh the rear torsion bar, im pretty sure its standard front anti roll bar jus with extended (threaded bar) drop links!

[projectpug 0]

I would keep your strut braces in tact and look at beefing up the rear to try and match your front then you will have a nicely balanced car. I am in the same boat as you trying to get my rear suspension uprated to match my fronts.

[wardy18 33 1 Cars]

But the problem is understeer on the front end, the back holds well an has loads of grip once the pressures are right! Jus seems like i need to loosen the front slightly to get more grip to pull me round the long corners

[welshpug 1,657]

if the rear is standard and you have stiff front springs it will understeer, wither use softer front springs or stiffer torsion bars

[wardy18 33 1 Cars]

ok ive checked and it has a 21.5 rear torsion, not sure what standard is, also has Skip Brown Camber Casters

 

still have no idea what load springs its running and the front arb is standard with like i said adjustable drop links

[brianthemagical 1]

What are the tyre temps like and the condition of the fronts? Might be worth doing a track day and having a play.

 

Are the tyres the same fornt ane rear? Does applying some power make a difference? Did you set the car up with no aero first?

Edited August 31, 2008 by brianthemagical

[bren_1.3 1]

standard torsion bars on a 205 gti are 19mm. what anti-roll bar is on the rear?

[tom_m 0]

if you've got the full skip brown rear end, you'll have 21mm torsion bars and a 23 mm arb iirc.

 

try unhooking the front arb all together. to get a fwd car to go round corners you want a stiff rear and a soft front.

 

if you've got coilovers try a softer set of springs? PTS matched 185lb per in springs with 21mm torsion bars in the rally handbook to give you some sort of idea

 

or, dare i say it, a little less of the old right foot?

Edited August 31, 2008 by tom_m

[wardy18 33 1 Cars]

What are the tyre temps like and the condition of the fronts? Might be worth doing a track day and having a play.

 

Are the tyres the same fornt ane rear? Does applying some power make a difference? Did you set the car up with no aero first?

 

well yes the tyres arent the greatest, am running 16" x 8J with Matadors which have already been throu a season, i will be purchasing a set of 15" 9J tyres for my new wheels for next season, hopefully this will help alot

 

i have no way of getting to a track day as on this little island there is no such thing lol

[wardy18 33 1 Cars]

if you've got the full skip brown rear end, you'll have 21mm torsion bars and a 23 mm arb iirc.

 

try unhooking the front arb all together. to get a fwd car to go round corners you want a stiff rear and a soft front.

 

if you've got coilovers try a softer set of springs? PTS matched 185lb per in springs with 21mm torsion bars in the rally handbook to give you some sort of idea

 

or, dare i say it, a little less of the old right foot?

 

Im not sure if its the full skip brown rear end, i will measure the rear torsion car, is this simply the diameter of it, i wouldnt even know which part to measure, ive never done much with the rear beam?!?! where do i measure for the arb!??!?

 

so you mean just remove the drop links comletely or just loosen the brackets to the front arb on the sub frame so it can move around!?

 

yeh its a full set of SPAX RSX

 

.......and uh hum yeh maybe ill try being a little less aggressive i think!! smooth is the key

[Miles 331 1 Cars]

As Tom said try removing the Front ARB, this suit's some and not other's mind, Also try one thing at a time and no more as you never know if anything makes a differance (Good or Bad).

What type of Diff (If any) are you running?

[wardy18 33 1 Cars]

Ah ok so completely remove the front arb altogether, well to save massive work between runs i may jus remove the drop links an try a run an see how it handles! As long as the arb ends dont hang too low an catch on the course at all!

 

i run a gripper diff as advised by nick bv shenpar

[tom_m 0]

so you mean just remove the drop links completely or just loosen the brackets to the front arb on the sub frame so it can move around!?

 

yeah one of the drop links removed is enough to stop the arb doing its job. just be sure to secure it out the way if you remove both, you don't want it flailing around down there.

[tom_m 0]

i run a gripper diff as advised by nick bv shenpar

 

ahh that shed a little more light on things, if you're understeering with a diff i'd hazzard a guess you're being too aggressive with the throttle and locking it, once both wheels are spinning the car will plow on regardless of the fancy nature of the diffs internals.

[Tom Fenton 1,542]

To add to what everyone else has said, I think a wise move would be to establish exactly what you have, so spring rates, damper settings, anti roll bar sizes, rear torsion bar sizes, front camber, castor & toe, rear camber & toe, and document all of these.

 

Knowledge is power as they say. You can then move forward altering one thing at a time and record the results. A methodical approach like this is the only way to effectively develop competition car suspension IMO.

[wardy18 33 1 Cars]

Ah ok then so try an stay off the gas an drive it round instead of too much power an spinnin, im usually almost on full right hand lock with lots of power to get round this one long right hander

 

will definitely try un attaching the front arb thou

[wardy18 33 1 Cars]

To add to what everyone else has said, I think a wise move would be to establish exactly what you have, so spring rates, damper settings, anti roll bar sizes, rear torsion bar sizes, front camber, castor & toe, rear camber & toe, and document all of these.

 

Knowledge is power as they say. You can then move forward altering one thing at a time and record the results. A methodical approach like this is the only way to effectively develop competition car suspension IMO.

 

good advise,ill get on the case

[James_R 3]

Just undo one drop link both ends, or the ARB is leaft "floating" not good.

 

With the diff in the car you shouldn't be understeering, or you're just entering the corner too fast/too stiff at the front.

 

Can you get the car in to over steer with agresive turn in?? If not then the rear is probabaly too soft, on a fast fast corner you want the car pretty much balance on the throttle with the tail pretty much hanging out/getting dragged along and the front points you where you want it to.

 

How tight is the corner if? if you're using full lock, that's mental if it's open and fast