Coil Springs

Post discussions on potential upgrades and modifications here, as well as documenting successfully implemented projects.

Moderator: Board Moderators

Post Reply
guysnook
Verified Poster
Posts: 7
Joined: Thu Aug 03, 2017 12:00

Coil Springs

Post by guysnook »

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

Pete Boole
Senior Poster
Posts: 3720
Joined: Tue Apr 04, 2006 21:28
Model: Elite
Colour: Monaco White
Year: 1974
Location: Nottingham

Re: Coil Springs

Post by Pete Boole »

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 :oops:). Great on the track - horrible on the road!!

Are your dampers adjustable? Single or double?

Pete

guysnook
Verified Poster
Posts: 7
Joined: Thu Aug 03, 2017 12:00

Re: Coil Springs

Post by guysnook »

That sounds like fun!!

The Quantums are single / adjustable.

moriniman
Junior Poster
Posts: 25
Joined: Tue Aug 11, 2020 23:27
Model: Excel
Colour: White
Year: 1985

Re: Coil Springs

Post by moriniman »

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

User avatar
Hawaiis0
Senior Poster
Posts: 4144
Joined: Sun Jun 30, 2013 18:39
Model: Excel SA (No 3); Elite 504
Colour: BRG; Dirty White
Year: 1986
Location: West Oxfordshire

Re: Coil Springs

Post by Hawaiis0 »

I think the 350/300 rate is for the SA with the heavier gearbox
Nothing is fool proof. Fools are clever!

moriniman
Junior Poster
Posts: 25
Joined: Tue Aug 11, 2020 23:27
Model: Excel
Colour: White
Year: 1985

Re: Coil Springs

Post by moriniman »

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.

Post Reply