roll bar settings

rs phil · Sep 6, 2009

had car around mondello pk on friday,understeer was shocking worse than ever before

left the rs with manthey earlier this year for goe corner weight etc for ring setup,which feels like it has a lot of roll,which would make sense for there

cup diff plates also,i know this gives more understeer off the power but even lifting and powering back on still wouldnt hook up on the front,rear grip was bril

front and rear bars are at mid positions, i was going to stiffen rear bar to last setting and soften front bar one setting?

im running michelin cups and rears are using all the tyre but fronts have maybe another 10mm to outer edge to use,3deg front and 2.5 rear camber,and i would think toe in on the front
i would think a setup for nurburgring gp track would be more suitable

any help would be appreciated as i hate understeer...would prefer oversteer[

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Melv · Sep 6, 2009

Try full soft at the front and full hard at the rear, maybe back one stop on the rear to suit your style -the car rewards trail braking.............

NB Dya have a strut brace?

chfs911 · Sep 6, 2009

Full stiff on the front and mid on the back works best. If you soften the front and stiffen the rear you'll get more oversteer all right.

If the former does not work then look at the tyre camber settings. Try 225/45 on the fronts for more grip.

rs phil · Sep 6, 2009

forgot to say im running bbs race rims,18s- 10 rear 265,and 8.5 front on 225

i would have thought soften front and stiffen rear to reduce understeer

like you say melv,i think full hard on rear and back one click or full soft on front

i noticed manthey lowered the rear alot and raised the front maybe 5mm,so alot less rake,which would give so much rear grip i guess

i have never adjusted them so i am looking foward to see the difference

chfs911 · Sep 6, 2009

So do I, 18" 265 and 225. Can't see why you'd need to go full soft on the front unless your tyres are shot!

Check the manufactures dates.

rs phil · Sep 6, 2009

bought tyres this year and lots left on them especially the fronts

if i stiffen front bar and leave my rear as is (mid) will i not get more understeer?,i know the diff has a lot to do with it also

it used to be quite tail happy prior to set up and diff rebuild,but this was due to spinning inside wheel,mondello is all 2nd 3 rd gear corners so it need to be sharper

Stewart H · Sep 6, 2009

I run mid point on the front and full stiff on the rear. It has virtually cured understeer - does try to oversteer as its basic response now though.

rs phil · Sep 6, 2009

probably worth trying rear bar first and work from there?

rs phil · Sep 8, 2009

this is how bad it was[

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http://www.youtube.com/watch?v=Nqk_ai_W8_4

carreraboy · Sep 9, 2009

full front soft rear

paul howells · Sep 9, 2009

That is shocking handling from a rs
Tires up to temp?Pressures? oversteer and understeer.
wooly turn in.
what rake do you now have.
do you have the figs for the new set up and the old.

PhilRS · Sep 9, 2009

It does not look too good!

Looks to me like badly overheated tyres. What were your pressures? They should be between 1.9 to 2.1 bars all round, depending on taste. You look like you are driving with 2.5+ bars there.

rs phil · Sep 9, 2009

dont know what the geo is,have emailed manthey but no reply as yet

yes its shocking wanted to burn the car after a couple of laps,everyone was struggling with understeer that day,some drifting had been on the week before so track was not great either

i was running 30psi hot on front and 38 psi hot on rear,i tried lower pressure before with cups at rear and car was very oversteer,but then the diff was worn

the oversteer was due to rears overheating as i was out for so long trying to get the fronts to work...its was better when it had knackered diff and no geo done[

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paul howells · Sep 9, 2009

Mich cups should be around 32psi hot all round.
New diff plates will cause the car to push,whats the back end like on lift off.What diff plate percentage are you running?
If your backs were overheated the fronts would certainly be up to temp/correct pressure.
There are so many things that effect a 964,how much fuel in etc
Get tire temps and pressures right first,then play with your roll bars,full stiff rear and front one off full stiff on a dry day,check pressures,if still understeering soften the front bar one hole or half hole at a time.
Manthey settings are normally good,ring settings are not always good for tracks.
How old are your tires?

PhilRS · Sep 9, 2009

ORIGINAL: paul howells

How old are your tires?

Good point! I know someone who ran a 911 with Michelin Cups all round, but one of the front tyres was one or two years older than the three others (but had same thread depth). The car was awful to drive, unbalanced with *massive* understeer coming from the older tyre. Those nice oils in tyres like to evaporate!

BTW, 38 psi is 2.65 bar which is of course way too high.

Hacki · Sep 9, 2009

ORIGINAL: paul howells

Get tire temps and pressures right first,then play with your roll bars,full stiff rear and front one off full stiff on a dry day,check pressures,if still understeering soften the front bar one hole or half hole at a time.

Perfect way to do it. See how it reacts, and then set up the rollbars. Make sure it´s neutral in fast corners, you might have to accept very little understeer in slow corners then. Max pressure in hot tyres 2.4 bar.

rs phil · Sep 9, 2009

where is date on cups?

Hacki · Sep 9, 2009

ORIGINAL: PhilRS

ORIGINAL: paul howells

How old are your tires?

Click to expand...

Good point! I know someone who ran a 911 with Michelin Cups all round, but one of the front tyres was one or two years older than the three others (but had same thread depth). The car was awful to drive, unbalanced with *massive* understeer coming from the older tyre. Those nice oils in tyres like to evaporate!

BTW, 38 psi is 2.65 bar which is of course way too high.

Actually a good point! First step is a proper set of tyres, same age (not too old), same tread wear and maybe you´ll have to run it on your car for a few hundred km before you start setting the car up. Even a perfect set up won´t work with bad or mixed tyres.

The video actually looks like a tyre problem to me.

rs phil · Sep 9, 2009

bought the tyres earlier this year from simply tyres...had quick look cant find date on them, front has 2008,and rear has 1908..dont think these mean anything

handled ok apart from diff before i got manthey to sort geo and diff,and was great around the ring,spoke with 3 other guys and they said they were sufffering from understeer also...but not as bad as mine, same tyres for all 3 occasions

so maybe my rear pressure were too high,track was bad grip due to drifters laying down poo poo rubber,and my bars need little bit of tweaking,spoke to some people and recomended softer rear bar is a must for mondello

what pressure start cold with cups?cheer for all the help