View Full Version : spring rates
07-15-2010, 07:54 PM
5th coil progressive spring at 34" does it work?want to try what will it do?how soft dare go on lr with a stacked setup have a 225 now and want to stack it with a 400 will give me a 144#. to lite?I need ti tighten up on throttle in midle up on track.... maybe a rf tie down? NEED HELP. Have to set-up for driver
07-16-2010, 02:15 PM
Sounds like if all you are trying to do is tighten the car from the center off (on the throttle, or when the driver picks the throttle back up) All you would really need to do is increase wedge.
Increasing wedge will in turn free the car up off the throttle. So to compensate for that, I would soften the RF 25-50# and let it ride.
Doing too many changes like you are describing will get you out in left field in a hurry. I'd make smaller changes and really take notes with your driver on how they affect the car.
Stacking the LR allows you to run a softer rate of spring on the LR and still hold the car up without the threat of coil bind. Keep in mind when you soften the spring it is going to free the car up on entry off the throttle (similar to the wedge adjustment). So softening the RF again would be necessary.
We've run LR stacked with various combinations as well as barrel and normal springs. We always seemed best/most consistant on a plain 200-225# (we run 14").
The 5th coil thing we usually ran farther out than 34". Rule of thumb the closer to the rear end housing the stiffer the spring you need to run because of less travel. Think of it as having a 100# spring for the first inch or two of travel when you normally have a 325-350# spring there. It doesn't provide the instant traction/thrust you will be used to and if you have an engine with a fair amount of torq. the driver may have issues with breaking the tires loose in the slick.
Go out to 36"-38" with the progressive on the lift bar. The traction again won't be as instant, but similar to what it would be like with it out that far and a softer spring.
The best conditions we found to use the progressive on the lift bar is on a tacky track that is a little rough or whoopy. When your car scotches and does that shutter thing and the engine bogs and the car almost looks like its hopping. The progressive helps smooth that out.
It can work on a slick track but alot of factors have to go in its favor (engine/driver/setup combo and the drivers preference on what they like the feel of).
Hope this helps on your decision.
WV Race Fan
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