The Lotus Grand Tourers

I cracked/broke a front spring on my Excel Se (1987) yesterday so need to sort a replacement. The car had the Lotus Bits suspension upgrades some years ago and has since had a set of custom Quantum dampers.

The car gets used on track days and I'd like to use stiffer springs as replacements.

Does anyone have any experience of this and suggestions on spring rates?

Thanks

My experience probably won't help you very much as it was in an Excel with a 5.7 litre V8 in it. I ended up with 680 lb/in springs at the front (cannot remember what the back was ). Great on the track - horrible on the road!!

Are your dampers adjustable? Single or double?

Pete

That sounds like fun!!

The Quantums are single / adjustable.

Stock rates (pre 1989) are;

300 lb/in front
250 lb/in rear.

I have a pair of post '89 rears and they appear to be a little softer.

My '88 is on AVOs with adjustable spring platforms and 2.25" coils and a handwritten note in the back of the workshop manual that came with the car says;

350 lb/in froint
300 lb/in rear

Ride quality is still pretty good, probably in part due to the fact that it has adaptors so the spring load still goes into the chassis, not through the damper top mount. It doesn't use the rubber spring isolators though. Poly bottom bushes are all of course splitting.

Even before I bought this car, I was thinking about suspension for my '85 project Excel. It has dampers with adjustable spring platforms and I've just machined up adaptors to allow use of the spring seat on the chassis and also the isolators.

https://youtu.be/HhPO2el09Cw

I think the 350/300 rate is for the SA with the heavier gearbox

Hawaiis0 wrote: ↑

Tue Mar 12, 2024 23:20

I think the 350/300 rate is for the SA with the heavier gearbox

The auto box isn't made of cast Iron you know!

The part numbers only differ between pre and post '89 cars, not between base, SE and SA.

The note, written on a blank page at the back of the manual almost certainly refers to the spring/damper kit fitted to my car.