S3 rear spring length

Simple question: what is the free length of standard rear springs on an S3 Elan?
Jim

from the W/S manual

Thanks for that, I looked in Bucklands Bible but never thought of the manual. So…8 inches fitted and 14.71 free, but how long should it be, fitted, with the wheel off but jacked up at the chassis?
Jim

My S4 Sprint is 11 inches as you described. Hope it helps.

Jim

What are you trying to determine from this measurement as it relates more to the shocker rod length and not the spring.

regards
Rohan

Rohan,
My car sits a bit low at the rear despite torquing up the wishbones etc. as prescribed. It had new Tony Thompson standard springs and inserts about 18,000 miles ago and has always been low, to the detriment of the exhaust. With the car jacked up at the chassis, wheel off, but everything connected the measurement of the spring length is just over 10". I`m wondering if a spacer at the base (or top) of the spring would be a good or terrible idea. I occasionally use the car on circuits but not competitively, but we mostly do historic rallies which sometimes set the regularities and tests on less than perfect surfaces.
Jim

Jim

The spring length you are measuring is set by the shocker rod length and has nothing to do with the ride height.

What is you ride height with normal 2 person load. If its lower than the Lotus specification allowing for any difference in tyre diameters between the Lotus original and what you use now then then your springs are either too short a free length or too soft a spring rate.

Regardless of the actual ride height and why it is what it is, the real issue is what do you need to do to avoid the exhaust hitting the road.

You really have a possible 3 options assuming all the other components are in good condition and you dont want to go to taller tyres…

a. Longer springs or spacers as you suggest to increase ride height at current spring rate.
b. Stiffer springs which can be used to increase ride height depending on their length but also will reduce bump deflection and help prevent the exhaust hitting the road. If changing the rears you also need to change the front springs to keep the handling in balance.
c. Stiffer or longer rubber springs ( bump rubbers) on the shock struts to restrict maximum deflection at full bump to prevent the exhaust hitting. Alternatively you can put plastic spacers on the orginal rubber springs to bring them into play earlier. These springs deteroriate with age and may need replacing if gone soft. Restrciing full bump deflection a little on the Elan has some handling benefits also in my ecperience.

cheers
Rohan