Handling

leaded · 18-04-2014, 10:30 PM

I love the stock CSL handling but on track the front end understeer quickly became the limit and after going to Spa last year and seeing the performance of modded suspension and top mount setup cars I felt I needed to make that jump.

Over the winter the car has had all the suspension bushes replaced, subframe boot floor replaced and new rear subframe bushes, Ohlins road and track suspension and Turner top mounts fitted. Simpsons set the Geo up, Road and also a track setting with the front.

My problem is the car feels awful, I've messed up BMWs ultimate creation!

It feels like it's going to spit me off the road at any second.

The front end at speed wanders around, it feels like windy weather blowing the car around. Under braking the car will pull left or right and I end up fighting the steering wheel. The car turns fast and is much more responsive so much so that it feels it can get stuck turning and you have to back off on the steering input.

Maybe it needs a bit of time to get used to it but it doesn't feel great, I'm always on edge wondering what's coming next.

The Turner top mounts were fitted and the castor adjustment is set to the indicated 0 on the mount. Simpsons didn't check the castor but set the car to slight toe in, 1.75 degrees neg camber front for the road. I have crap tyres on the back (Michelin SS front) which they thought could be the problem (back tyres) but it feels more severe than that.

Is anyone running the turner top mounts and if so what is the castor setting set too?

Anyone got any thoughts on causes, how do people find their cars drive on the road with similar setups?

shane@mbtech · 19-04-2014, 10:21 AM

Get the geo checked. Sounds like its out to me.

shane@mbtech · 19-04-2014, 10:22 AM

Sounds as though front is toeing in by the description you give.

**shimmy** · 19-04-2014, 10:28 AM

Get front toe checked incase they have set it track instead of road and then when it is moved it might have gone too far to toe in.

shane@mbtech · 19-04-2014, 10:28 AM

Toeing in too much

JBird · 19-04-2014, 10:31 AM

I'd try the car with something like pilot sports all round before investigating further. Some of the characteristics you are describing can occur on a simple road car on a motorway if bad enough tyres are fitted. Test driver from BMW just told me supersports are known for some instability, and with crap on the rear you could be magnifying the issue. Maybe sace the SSs for the road and use something else on track???

leaded · 19-04-2014, 04:44 PM

Thanks for help. The Geo has just been done by Simpsons. It does feel like a toe out problem but it's set on the road setting with toe in not the track setting.

Has anyone got a picture of their turner adjustable top mounts on the car they could post please. Simpson said they didn't check the castor and I suspect this could be the cause as it's set to the max setting, opposite to what turner suggest when fitting them.

Just been in Germany and can't go over 100mph due to instability, car is horrid to drive.

Tyres are the same as I was using before I changed the setup and ran fine however I have got a set of cups to try.

**alexk** · 19-04-2014, 05:35 PM

Additional caster is good for turn in and stability (also return of steering wheel to center).
The CSL has 7.5deg caster from the factory, I run in mine aprox. 9.5deg.

There is something else wrong with your car.
What exactly do you mean the car is not stable.
Is it difficult to drive it in a straight line ?
Is it doing strange weight transfers ?
Can you elaborate ?

leaded · 19-04-2014, 07:49 PM

Need to check castor is right and set to standard CSL setting so I can rule that out.

Does the castor look right in the pics? It is set to the maximum fwd. so to adjust would move the shock top towards the back of the car and therefore more castor.

Got a track event tomorrow so might just move it to the other extreme and see if it makes a difference. Changing the castor shouldn't effect the camber setting I don't think but maybe the toe slightly. Worth a try anyhow.

leaded · 19-04-2014, 07:50 PM

Passenger side.

18-04-2014, 10:30 PM	#1
leaded S3 - On the open road Join Date: Nov 2011 Posts: 83 Casino cash: $2452	Handling I love the stock CSL handling but on track the front end understeer quickly became the limit and after going to Spa last year and seeing the performance of modded suspension and top mount setup cars I felt I needed to make that jump. Over the winter the car has had all the suspension bushes replaced, subframe boot floor replaced and new rear subframe bushes, Ohlins road and track suspension and Turner top mounts fitted. Simpsons set the Geo up, Road and also a track setting with the front. My problem is the car feels awful, I've messed up BMWs ultimate creation! It feels like it's going to spit me off the road at any second. The front end at speed wanders around, it feels like windy weather blowing the car around. Under braking the car will pull left or right and I end up fighting the steering wheel. The car turns fast and is much more responsive so much so that it feels it can get stuck turning and you have to back off on the steering input. Maybe it needs a bit of time to get used to it but it doesn't feel great, I'm always on edge wondering what's coming next. The Turner top mounts were fitted and the castor adjustment is set to the indicated 0 on the mount. Simpsons didn't check the castor but set the car to slight toe in, 1.75 degrees neg camber front for the road. I have crap tyres on the back (Michelin SS front) which they thought could be the problem (back tyres) but it feels more severe than that. Is anyone running the turner top mounts and if so what is the castor setting set too? Anyone got any thoughts on causes, how do people find their cars drive on the road with similar setups?

19-04-2014, 10:28 AM	#4
shimmy CSL Register Uber-poster! Join Date: Apr 2008 Location: Uk Posts: 14,646 Casino cash: $43909	Get front toe checked incase they have set it track instead of road and then when it is moved it might have gone too far to toe in. __________________ .

19-04-2014, 05:35 PM	#8
alexk Driving it like I nicked it Join Date: Mar 2009 Posts: 2,785 Casino cash: $29948	Additional caster is good for turn in and stability (also return of steering wheel to center). The CSL has 7.5deg caster from the factory, I run in mine aprox. 9.5deg. There is something else wrong with your car. What exactly do you mean the car is not stable. Is it difficult to drive it in a straight line ? Is it doing strange weight transfers ? Can you elaborate ? __________________ www.clubcsl.com - I am a BMW Motorsport fan ! My youtube channel is here

19-04-2014, 10:21 AM	#2
shane@mbtech CSL Register Uber-poster! Join Date: Feb 2009 Location: warrington Posts: 5,419 Casino cash: $19783	Get the geo checked. Sounds like its out to me.

19-04-2014, 10:22 AM	#3
shane@mbtech CSL Register Uber-poster! Join Date: Feb 2009 Location: warrington Posts: 5,419 Casino cash: $19783	Sounds as though front is toeing in by the description you give.

19-04-2014, 10:31 AM	#6
JBird S5 - Full Throttle Join Date: Mar 2012 Location: Munich Posts: 280 Casino cash: $5259	I'd try the car with something like pilot sports all round before investigating further. Some of the characteristics you are describing can occur on a simple road car on a motorway if bad enough tyres are fitted. Test driver from BMW just told me supersports are known for some instability, and with crap on the rear you could be magnifying the issue. Maybe sace the SSs for the road and use something else on track???

19-04-2014, 04:44 PM	#7
leaded S3 - On the open road Join Date: Nov 2011 Posts: 83 Casino cash: $2452	Thanks for help. The Geo has just been done by Simpsons. It does feel like a toe out problem but it's set on the road setting with toe in not the track setting. Has anyone got a picture of their turner adjustable top mounts on the car they could post please. Simpson said they didn't check the castor and I suspect this could be the cause as it's set to the max setting, opposite to what turner suggest when fitting them. Just been in Germany and can't go over 100mph due to instability, car is horrid to drive. Tyres are the same as I was using before I changed the setup and ran fine however I have got a set of cups to try.