progressive spring on torque arm

[rubbinsracin]

i know the progressive spring has been talked abotu before, but i couldnt find anything that talks about which one to use. I have found some different options around and wondered what would be the best for a 602 car on a big 3/8th track that is pretty tacky all night long..

Here are the different things i have found 125lbs progressing to 500lbs, 225lbs to 500lbs, 200lbs to 600lbs, and a new one from afco appears to have alot more tightly wound coils that would give an even higher rate, but it does not tell what the rates actually are.

any input would be great. we have always just ran a standard spring under there ranging from 200lbs to a 450lb spring when we were trying different stuff.

[MasterSbilt_Racer]

http://www.4m.net/showthread.php?232...ressive+spring

If you aren't hooking up a legal 602 on a tacky track that size, something is seriously awry with your race car. LOL

[talclipse]

At racewise last year AFCO was pumping their new progressive 5th coil as cutting lap times by .1-.2 seconds per lap (with all these parts that we buy to cut .1-.2 seconds off per lap I don't understand why we all aren't breaking the sound barrier). As best I can recall they never really mentioned the specific rates; but did indicate it was much more progressive than their previous springs.

With all of that said there are a LOT of races out there being won the standard 300-350 spring on the 5th coil. If you are struggling with forward drive off with a crate car I would venture to bet that you have some setup issues elsewhere or possible running an EXTREMELY hard tire. I would think you may be looking in the wrong place to improve your handling. Look specifically at your entry handling and how you/ the driver is getting the car IN the corner.

[rubbinsracin]

The problem isn't hooking it up. We have just been hearing the same thing as above about it being pushed at the race wise classes. We have ran the progressive spring before with success but never on a crate car. We are just thinking of trying it but never realized that there were so many options i.rate. figure it can be used as a tuning tool like everything else. Or would we be just best off with standard spring

[MasterSbilt_Racer]

Don't get me wrong. I understand that the 5th coil plays some small role in the overall ride rate of the rear suspension. However, I don't mess with the 5th coil unless I have a problem putting the power to the ground. Lighting tires up on exit? Busting them loose halfway down the straight? Backing out of the gas on exit because the front wheels got too light?

I have no crate experience. But I have driven 400 to 500 hp lates against supers on small tracks. I could just pretty much hold it to the wood on tacky to average tracks.

I would suspect you need to work on carrying corner speed without bogging down your engine. I don't see what you hope to gain.

You seem determined to give it a try. Don't let me or anyone else stop you.

[talclipse]

The problem isn't hooking it up. We have just been hearing the same thing as above about it being pushed at the race wise classes. We have ran the progressive spring before with success but never on a crate car. We are just thinking of trying it but never realized that there were so many options i.rate. figure it can be used as a tuning tool like everything else. Or would we be just best off with standard spring

For me, as just another Saturday night hack, the thing I want most from my car is consistency with a progressive spring I think you lose some of the predictability due to the progressive vs. linear nature of the springs.

Only you can determine if its something that will benefit your team and is worth the time and $$$ to develop as part of your program. Based on my experience with the progressive springs (going way back here) it was one of those things that wound up in the "Well we tried it" pile next to the rubber biscuit J bar, and several other "speed secrets".

[rubbinsracin]

No. We aren't for sure going to run one at all. Thinking of leaving the 300lb spring we ran last year with our old regular late model motor. Anything to gain an edge you know.

[hpmaster]

We used one last year and had good results. What we did learn is the amont of preload was near 0 to only 1/2" or so to get changes from slick to tacky, which was less than what AFCO recomended. We made an panel we pulled off to the right of the driver on the deck so you could just adjust it in a minute. I would recomend checking it on a spring checker so you see what it actually does as to limiting total movement, easier to watch than to explain.