Road / Track Suspension Compromise

[Bob Corb]

I originally specced my 7 with a sort of SLR race suspension set up (SLR dampers, 250lb/215lb front/rear (green) springs, 5/8s front and 9/16? rear (blue bushes) ARB). When I first got the car on the car the back end was all over the place so I set the rear ARB to full soft and changed the rear springs back to std non linear rate type.

 

This appears to work very well on the track giving mild understeer which is easily balanced out with power and a predictable wag if you lift off. Unfortunately the car still isn't great on typical country roads. It feels like the damping is too hard whilst skitting over small ruts in the road although when the car lands after "low flying" from hump back bridges the suspension take up is very good (although I should fit Watts links as the rear occaisonally bump steers on take off leading me to land with a bit of opposite lock!).

 

I was wondering if anyone had any experience with Ohlins dampers either the mono tube single adjustment sort or the 2 way adjustable remote reservoir types as Ohlins Racing UK claim "Our Road and Track dampers are renowned for their ride quality and driver comfort" At £380 (mon with spring) or £430 (remote thingies without spring) each they are a bit pricey to just "give em a try".

 

I noticed some Ohlins dampers on the R500 prototype a couple of years ago although I haven't seen any on production cars.

 

I was also wondering if changing from stiff/heavy A032s to CR500s would reduce unsprung weight to an extent that control would be improved.

 

Cheers

 

Bob

[Peter Carmichael]

Caterham were testing the valving with the 4 way adjustable Ohlins dampers, in order to put cheaper Bilsteins into production.

 

I can point you in the direction of Nitron for "Ohlins quality" at a cheaper price. Guy at Nitron thinks the Caterham Bilsteins have too much low speed damping and has specced a much more linear valving for my dampers. However this will not necessarily fix your problem.

 

Getting into the realms of adjustable damping gives you more variables to get right so that the whole show works together. You may find yourself lost between settings before you hit the sweet spot. FWIW, I reckon the 250-350 lb/in range is right for the front and somewhere around 120-150lb/in is right at the back. The standard progressive rears are in this range, but are too long to fit Nitron dampers.

 

Alternatively, you could try a set of standard spec dampers as opposed to the SLR racers. The race dampers have been described to me as being hideously compromised and cause of the entire basis of set up to be skewed around their bizarre characteristics. They are only viable because it is a single make series. (If you want to give standard spec a try, I have a full set off the car and available - these are the springs and dampers I ran at Curborough in May and at Llandow so they certainly work well enough and they have been the basis of my road set up for 5 years)

 

Peter *eek*Loadsachequestubs Carmichael