Breaking traction- bumpy surfaces?

[Edmundo2]

I recently bought a nice 987.1 Cayman S. It's well sorted and runs KW clubsport coil overs with R spec heights and geo...

I'm starting to notice that when driving on rippled or poor surfaces under acceleration in lower gears the car seems to break traction a bit too readily and I find myself backing off a touch to be sympathetic to the drive train. It sort of scrabbles for traction a bit too much on surfaces I would think it should just get the power down on..

I could just keep my foot planted but I'm just canvassing thoughts on the cause..? Has anyone else found similar..?

I'm not sure if it's something to do with the KW settings or whether its "something they all do Sir" or whether an LSD is needed if want to limit it?

Any thoughts?

[supersport]

What state are your tyres in. I have found a number of my cars will start to do this, especially in damp or cold conditions when the tyres are shot.

[Evo9lution]

Assuming that it's just the rear breaking traction? Was the car mainly used on track before as, if so, it may be a little too stiff for bumpy roads.

You could soften off the bump/rebound on the rear but that will affect the overall handling of the car (more towards understeer) so maybe best to soften off all round a click (or two, if necessary). Or, have a play and soften the rear to see how you like that vs softening all round.

Also, has it got a/m ARBs? If so, this may be reducing flex, thereby causing traction issues on bumpy roads, so if they are adjustable you could try adjusting the rear to a softer setting (again, it may affect the handling of the car a little but maybe not too much on the road). Could always try this first as some flex can help with traction.

Of course, it could also be tyres, if they're old or had hard use (seen too many heat cycles), or lacking tread.

[Jazzer]

You need to be careful with applying power on a rough surface or cambered road, as you can very easily be thrown off line and into trouble.

A smoother, gentler approach is far more effective-and safe!

I once witnessed an M3 literally fly into a tree when going up a hill for this very reason.

You live and learn, as I did with my first RWD car.

[Edmundo2]

Hi.

Tyres are new Michelin Pilot Sport 3.

Re driving style I appreciate comments and whilst I'm not Ari Vatenan I've been hillclimbing single seaters with three times the power to weight ratio of the croc for the last 10 years so it's not a lack of rwd experience.. ( lack of talent perhaps..!? )

My suspicion is just a lack of compliance. I don't find it too harsh for B road blasts and its great through the corners. I notice it in a straight line which suggests to me it's not the arb's?

Will try softening off a couple of clicks perhaps with a a tad more on the back to see?

It does seem to spin an inside wheel pretty easily on off camber tight corners also.. I appreciate its open diff so LSD would sort this but not sure if it also points towards stiffness/rebound etc?

Edited by Edmundo2 on Tuesday 19th May 23:04

[edc]

Michelin Pilot Sport 3 is a middle of the road tyre.

[Edmundo2]

edc said:

Michelin Pilot Sport 3 is a middle of the road tyre.

...but new and driven in a straight line on a warm dry road with 300 Bhp in 1250kgs.....its not the tyre. It can't grip if it's not in contact with the surface

[edc]

Sure but the tyre choice seems odd for the type of car you are aiming for. I would soften off the dampers and try again down the same road.

[Evo9lution]

Maybe MPS4 / MPS4S would have better characteristics (Cup 2s even more so) but I think that MPS3 should be fine in the main?

Even if in a straight line, if the road is uneven, stiffer ARBs will make traction a little worse due to reduction in flex (the more the car can flex the better the tyres can grip the road). It will be less noticeable on smooth surfaces (in a straight line) as the car only squats to the rear rather than side-to-side (here a softer damper setting allows the car to squat more and allows more mass to push down on the rear axle and creates more grip ...).

Just food for thought but this basic article may help a little: https://5xracing.com/p-24306-sway-bar-tuning.html

Try softening a click and see if that makes a difference. See if the rear ARB can be loosened off and see if that makes a difference. You may need to try a combination to get it right.

I doubt it will be this but it may be worth checking, when the bushes for the rear ARB mounts started to go in my Evo it made the car feel very light & floaty in the rear under hard acceleration. Maybe check this too ...

[Edmundo2]

Apologies, tyres are MPS4 not 3... My understanding is they are pretty well regarded on a Cayman. I have no frame of reference yet but feel pretty good to me..It's just what was on the car when I bought it with no more than about 500 miles on them. I also want it to be ok in wet so hopefully they are a good choice?

Will try soften a touch as you say

[Evo9lution]

MPS4 are good mate

[Dr S]

Lack of traction is often a sign of too firm of a set-up. I'd have someone experienced softening your set-up and see if you continue experiencing these issues

[Ultrafunkula]

Might be worth checking tyre pressures too, just to be sure

[frayz]

KW Clubsports are a superb damper as are the MPS4 you're running.
Back off the bump and rebound to a sensible level and start there. Sounds like you have a great setup to play with and see no reason why you shouldn't be able to get it exactly as you want it.

[AW10]

When was a proper 4 wheel alignment last done?

[Edmundo2]

Hi. Will check but pretty sure R spec geo done not longer before I bought it..To be honest the ride is fantastic and it tracks and corners superbly...The breaking traction I mention is only under low gear acceleration across rippled surfaces so not a big or frequent issue..

I think it's more a reflection of our roads than the car but will try softening just a touch to see if it helps without compromising the ride or handling which are great..

[timg4d]

If it was you who got FTD at Harewood with the Force PT, lack of talent is not going to be the issue. I sometimes can unstick my Boxster briefly if there’s a bumpy section - not often, but if it does it’s usually when coming out of a junction and turning.