Cal Trac setup

[40Coupe]

I'm running Cal tracs on my '67 Camaro. Currently, I have them set with 1/2 turn of preload on each side with driver in car. I run AFCO DA's on all 4 corners, GM mono's out back and trick springs up front. I'm also running Hoosier C07 30 x 9 radials. On a well prepped track it hooks very consistently. On a poorly prepped track it will spin. What if any impact would taking out preload, even the possibility of running a gap do to the launch? I know it will certainly hit harder but will also be harder on the stock GM monoleaf springs.


I plan to do some preload tuning loops next time out. In previous testing it seemed like the combo has always wanted some preload.

Will significantly backing off the preload effect wheelie height?

[Richard Grant]

One half/one quarter a turn is a good setting. Less preload will increase your wheelie height. How old are your slicks? With your setup it will always be difficult to hook on a poorly preped track. New or almost new slicks are your best bet to hook consistently. Your problem is too much power for 9" slicks on a poor track. With that much power, I don't think you will ever hook consistently on poor track. Lots of luck.

[40Coupe]

Thanks for the reply Richard. Slicks are left over from last season. I plan to buy a new pair shortly.

I think I might try a little less preload just to see what happens......probably just go bumper on a good track and still spin on a bad one. LOL

[Geerhead55]

I know a lot of guys will toss the stock leaf springs and go with the Cal-Trac split leafsprings. They seem to ba able to take the "hit" a lot better. Go check out the big block Camaro stockers and talk to them. They're usually able to save you some guess work. We approached Dan Fletcher a few years back at Phoenix about this same issue and he was very helpful and friendly about it. ( Thanks Dan )
If you use the Cal-Trac springs you can get different front halves to alter the ride height if you chose if tire clearance is an issue. My 2 cents,,,,,,,,,,,,,, Danny Durham

[Tom Rix]

I agree with Danny. I have a 74 Buick Apollo (3400#) set up like yours with DA shocks front and back, Cal Tracs and Hoosier 9x30 CO6 radials. I had the same issue as you do. I played with Digital 7 programmable by taking timing out but it wasn't until I switched to the stiffest Cal Trac split mono that they offer that it made any difference. It now hooks great and 60's are from 1.27-1.30 consistently. If I have too little preload it will wheelstand pretty high for about 80-100'. Best change I made to the car!

Good luck!
Tom

[bob gonier]

Is your car a glide or a turbo ???? I dont think it will ever hook on a marginal track with a three speed and your power. Most of the people on this site race on an NHRA prepped track and thats a huge difference from what you race on. I race on a marginal track at best and I had no choice but to switch to a glide years ago to tame a bunch of the hit. With the turbo when it hooked it was great, but the problem was it didnt always hook. With the glide it always hooks. And in my case the glides actually faster to boot. Its not all about 60'............. Unless your running a Stocker.


JMO.........




bob

[40Coupe]

Thanks for the advice and real world results on the split mono's. This may be one of the puzzle pieces I'm missing. I'll contact Calvert and discuss my options.

Yes, I'm running a TH-400 with a heavy BBC up front. I realize it's not all about 60' but I built this combo to leave hard and produce wheels up launches. The downside is R & P wear and breakage. <frown>