Which track pack replacement springs?

[jah29]

Had the the track pack suspension off my car and measured the spring sizes. The fronts are 1.875" diameter and 8" long. The rear are also 1.875" diameter but are 9.625" long.

RE Suspension Inc. sells hyperco springs in these sizes in 25 lb/in increments:

1.875" I.D. Coil Over Spring, Coil Over Springs, Hypercoils, RE Suspension Inc.- Racing Shocks and Suspension

Allegedly the track pack springs are progressive, 180-271lb/in for the front and 266-371lb/in for the rear.

Requesting opinions about which replacement size I should get. I was hoping to reduce body roll a little bit, but not overpower the dampers.

I could just get 275 and 375 to just replace the progressive nature of the stockers. I could bump the rates up to 325/425 just like the ohlins. Higher?

Ideas?

thanks,
justin

[fpitas]

There's a rule-of-thumb that you can only go about 30% stiffer without needing a revalve, and I doubt that will make a significant difference to body roll. The Cup Car has 458/571 lb/in springs, that's more like it.

Track pack (Bilstein) vs Ohlins vs Nitrons

There are various anti-roll bar options available, too.

Track Alignment/Swaybar suggestions

And here's a discussion of body roll and the Elise/Exige:

BODY ROLL !!!

[jah29]

thanks for the 30% rule.

I could be wrong, but my theory is that the extra body role is from the first part of the progressive spring's travel. If we increase the front by 30% higher than the 271 of the higher half of the progressive rate, we get 352 in/lb. That's a lot more than the 180 in/lb of lower part of the progressive rate.

I don't really know.

justin

[fpitas]

Originally Posted by jah29

thanks for the 30% rule.

I could be wrong, but my theory is that the extra body role is from the first part of the progressive spring's travel. If we increase the front by 30% higher than the 271 of the higher half of the progressive rate, we get 352 in/lb. That's a lot more than the 180 in/lb of lower part of the progressive rate.

I don't really know.

justin

That may work out. The remaining question is whether springs are available that have the right pigtail ends as stock. Blackwatch used to sell stiffer springs to fit the stock perches, but I don't think Fred carries them anymore.

Blackwatch Racing - Lotus Elise and Exige Superchargers, Parts, and Accessories

[jah29]

False alarm!!

Probably can't get a full set off springs. Hyper co makes a range of weights in the 10 inch length, but the 8 inch lengths are only very low rates. way too low.

don't know of any other sources.

justin

[fpitas]

There is still some hope. People talked about a threaded sleeve kit to allow mounting standard dimension racing springs on Bilsteins in these threads:

Track pack (Bilstein) vs Ohlins vs Nitrons

Bilstein Coil Over Sleeve Kit

[AZReason]

I can find you what you need up to 600 lbs/in except for the 325 rate (300 or 350). Unfortunately you have to order from 3 different sources for it to work.
PM me if interested.