DragStuff

I have a set of Caltracs on a 68 Nova. At the initial settings, the car pushed hard to the driver's side. I added more preload to the driver's side, thinking that would make it go more straight. But, that made it worse! It pushed harder to the driver's side. So I took that back out and put some preload on the passenger side bar. That worked. I had to add a little at a time til I got it going straight as an arrow, so to speak. Can anyone tell me how and why?

Also, everything I have read says that I need around 4 degrees negative pinion angle for a car in my horsepower range. I had right around 7. I took 2 degrees out for about 5 degrees total to see if I could get a few more hundreths out of it. The next trip down the strip, the thing bound up and shook the whole way, .05 slower! Needless to say, I am putting the wedges back in.

I had Slide-a-Links on the car before the Caltracs. They seemed to be a lot less finicky than the Caltracs. By that I mean I had to do alot less adjusting to get the car going down the strip straight. And alot less aggavating. The lock nut on the front of the Caltracs between the pivot plates is a pain in the hiney to get to. I finally went to the flea market, bought two cheap chinese 1 1/8" wrenches, cut most of the boxed end off, and milled them down until they fit nicely between the plates. I have yet to get my 60's down where they were with the Slide-a-Links. The difference is only a couple of hundreths. Could be other diffrences I guess.

I put the Caltracs on the thing because everyone said they were the way to go. And they probably are. They are a little more robust than the Slide-a-Links. However, quality and craftmanship, in my opinion, are equal.

Here's some reading for you -

http://www.yellowbullet.com/forum/showt ... p?t=288916

Your first guess is what usually works, putting preload on the side it's driving to. What you're doing is cranking weight into that corner. Now why you had to do opposite is a good question. Just remember there are a lot of things that can make them do that. Uneven tire rollout or uneven tire pressures for example.

The other question is how did you set it up to begin with? Did you have the driver in the seat at race weight? Was you playing with gaps or initial preload?

Either of your pinion angles "should" have worked, you'll hear a lot of debate on that one. I am surprised the driveshaft? shook at 7 degrees? That's kinda odd... That pinion angle changes a lot from launch to say the 60' mark and of course power level, not sure you can say one angle fits all cars?

John_Heard wrote:Your first guess is what usually works, putting preload on the side it's driving to. What you're doing is cranking weight into that corner. Now why you had to do opposite is a good question. Just remember there are a lot of things that can make them do that. Uneven tire rollout or uneven tire pressures for example.

The other question is how did you set it up to begin with? Did you have the driver in the seat at race weight? Was you playing with gaps or initial preload?

Either of your pinion angles "should" have worked, you'll hear a lot of debate on that one. I am surprised the driveshaft? shook at 7 degrees? That's kinda odd... That pinion angle changes a lot from launch to say the 60' mark and of course power level, not sure you can say one angle fits all cars?

I cant reply!

This thing has wiped my reply out twice. I am kinda mad about it.

Far as I know nothing is broke on the forum?

It was probably me. I set it all up according to the Caltrac brochure.

At 7 degrees it wasn't binding or vibrating or anything like that. I was just searching for a little ET when I went to 5 degrees. I wound up at no preload or gap on the driver's side and a full turn on the passenger side. Thanks John and Mike.