ride-height Vauxhall race-damper

[Marius]

I´ve just gone through some pictures & videos from Curborough and saw that the rear end of my 7 is obviuosly higher than on many other cars. I´ve fitted the Bilstein Race-dampers (green springs, factory kit) which are height adjustable BUT I´m not sure about one thing:

 

I´ve cuurently adjusted the dampers so that the springs are just being unloaded when jacking the rear of the car up. My feeling sais that I should lower the rear-end further but then the spring would (theoretically) become a loose fit when the rear end lifts. This could happen at some place on the Nuerburgring so it´s worth thinking about.

 

Do I worry myself too much ? Can I lower the platforms further without fearing the spring to rattle around when being unloaded ? What did the race-teams with this damper-setup ?

 

By the way, dampers are mounted to the straight-through hole in the DeDion-Tube, not the lower thread.

 

Marius

[Paul Ranson]

You can put 'helper' springs between the spring seats and your main springs. These are very low rate and are ususally completely coil bound, but when the main spring fully extends they expand to take up the gap and keep everything in place.

 

DT catalogue, bottom left of p258 for example.

 

Paul

 

 

[Marius]

Hi Paul, that´s what I thought about but is that really the way everyone went ? There´s still so much thread left on the damper to lower the springs and I´m sure there are lots of Cat7s around who ride MUCH lower than me with the same dampers.

 

Hmmm....

 

Marius

[Peter Carmichael]

Marius,

 

Have a look at...Helper springs

[edmandsd]

Are these dampers the same as the ones they use on the front of the Vauxhall race cars ?

[Peter Carmichael]

moving to the lower damper mounting point would lower the car, but I suspect the real culprit is the rear spring rate (215lb/in). This is very high and you would be better off with something in the 140-160lb/in range.

[Peter Carmichael]

Dave,

 

The open and closed lengths are very much different for the rear dampers. The valving should be different also.

[edmandsd]

I guessed that would be the case Peter - I was misled by the green 250lb springs, which I agree seem far too hard for the rear.

[Peter Carmichael]

Greens for the rear are 215lb/in IIRC. I have some that have never been fitted because they are stupidly stiff.

[Marius]

But what did those Vauxhall racers do some years ago ? Did they use the lower thread on the DeDion (can´t imagine ´cause they tend to break) or did they just screw the springs down to Africa ? Helper-springs would have not been allowed or am I wrong ?

 

Peter, do you know what springs Caterham supplies for the rear end Bilstein race shocks ? Just a softer spring won´t lower the car or would it ????idea.gif

 

Marius

[Peter Carmichael]

I believe spring rates and anti-rollbars are free up to a limit (ie. no more than 400lb/in at the front) - it is just the dampers that are to a set specification.

 

A softer spring, with the platforms set to just touching the spring will compress further by the time it is loaded. A softer spring will give a lower ride height.

[Marius]

Hmm, so I´m slowly getting on now. Now which springs come as standard on the race-dampers rear ? Is that 215 or 250 and which ones would you lot recommend ? I mainly use the car on tracks so don´t worry for comfort. I read somewhere that Caterham once spent lots of hours on tracks to find this setup for the Vauxhall. So there must be something usefull about it.

 

Marius

[Bilbo]

Hi Marius

 

Well as you may have read I changed mine to Garry and Len's set up. The old Vauxhall race front springs were 250 lbs and the rears 215 lbs. I found the fronts too soft the rears to hard. Mind you I wa happy with them after the Spax when I bought them.

 

I use to set mine up so the back was 155 mm at the front of the rear wing and 145 at the rear of the front wishbone with me in the car. You need to remember I am 18.5 stone and that meant that the rear springs were never loose.

 

Not saying this is the best set up but it suited me with the de-dion rear. In fact I had the car ride height set a little too high, lots many speed bumps near me! Still do for that matter.

 

I am not going to comment on the new set up until after Cadwell on Friday. Seems I had it right for Curborough in the wet but not in the dry. Then again the clutch was slipping by then and I was blaming myself rather than the car. Still it seems too high at present. Oh setting it up by measurement with me in the car was not that far out when Garry flat floored the car. He did say the ride height was a little high but we kept my preference.

 

You need to remember that although the Vauxhall race set up was better, when I bought mine than the others, they were really provided to give conformity to the race series! Think they were the only adjustable ride height ones at the time. Were the Vauxhall race solid axel then (1992)?

 

 

1988 200 bhp, 146 ft lbs, 1700cc Cosworth BDX with Brooklands and Clamshell wings Q 979 CGY