Caltracs - install, set up, tuning

[milner351]

I was tipped off to a sticky on the YB forums about cal-trac set up. I've copied and pasted it into word, and edited it so it's easier to read. Do the guys with experience running caltracs on leaf spring cars have anything to add to this?

I don't expect my falcon to have the power to pull any wheelies, or destroy the tires - so it's probably not the best test case for this - but I thought others may benefit from the discussion.

1. FRONT: make sure the front control arm are not binding. this is one of the biggest issues. you can do this with after market bushings or control arms or just elbow grease. the control arms should fall on there own without having to push them down. the front springs need to be of a drag style that will give you the best weight tranfer you can AND MUST HAVE ATLEAST 5" OF UPWARD TRAVEL IN THE FRONT END. shocks should be of a good drag style i like d/a afco's. AFTER DOING ALL THE ABOVE SET THE SHOCKS AT FULL LOOSE FOR THE FIRST FEW RUNS.



2. FOR THE REAR same thing binding is the number 1 issue most the time it's in the shackels and the front leaf spring mounting bolt.. every car i see the bolts are over tightened you should be able to push the rear down 5-6" easy without the shock or caltrac mounted. lube all bushings well and don't over tighten. know that there’s no binding, any adjustment later will work..



3. i always start in the upper hole and preload of 1/16 gap. this will give you a lot of pressure over the rear tire. shock settings ON REAR, i always start at full tight on extension... know that the car is setup for a test pass have someone video it.. THE CAR WILL DO ONLY A few THINGS NOW.



a. IT WILL HOOK AND PULL A HUGE WHEELIE

- IF IT HOOKS AND PULLS A HUGE WHEELIE THEN TIGHTEN THE FRONT SHOCKS THIS SHOULD BE THE ONLY REASON TO TIGHTEN THE FRONT SHOCK

b. IT WILL HOOK AND DO WHAT YOU NEED

c. IT WILL HOOK AND pull left or right

- IF IT HOOKS AND PULLS TO THE RIGHT OR LEFT THEN PUT A LITTLE PRELOAD ON THE SIDE IT PULLS TO.

d. IT WILL HOOK AND SPIN 20FT OUT

- IF IT HOOKS AND SPINS 20FT OUT START LOOSENING THE EXTENSION ON THE REAR SHOCKS 1-2 CLICKS AT A TIME TO IT HOOKS AND STAYS ON THE REAR TIRE.

e. IT WILL KILL THE REAR TIRE BY HITTING IT WAY TO HARD

- IF IT KILLS THE REAR TIRE YOU NEED TO PUT THE BARS IN THE LOWER HOLE AND ADJUST THE SAME AS YOU WOULD IN THE UPPER HOLE.

[TC]

3. i always start in the upper hole and preload of 1/16 gap.

I'll have to dig up my installation instruction on the Cal-Trac's I put on the '71 GMC, but if I remember right there isn't suppose to be any gap, it is suppose to rest on the spring on the drivers side and your suppose to put a 1/2 or 1 full turn of preload on the passenger side....... Or at least that is how I remember it.........

[Joe Grippo]

That YB info is pretty much it. The only thing I'll add is I always make my adjustments to the bars with me in the car and I'll have my brother or buddy set them. I don't use any pre-load and my gap is a little less than 1/16", Early on John told me to use a dime and set them so it just slides out from between the spring and the stop bolt. I run mine in the lower hole and I use his shocks at all four corners. I made 5 runs on Sunday (2 time shots and 3 rounds) all 60' times were between 1.403 - 1.409!

By the way Milner, I will be at Milan next weekend for the NMCA/CJ Shoot-Out...Let me know if you are going to be at the track!

[milner351]

Totally Cool Joe! I will probably be thrashing on the Falcon - but would love to meet up with you somehow, my shop is just North of I94 near the 275 interchange, about 45 minutes from Milan.

I can only dream of being as fast or consistant as you're car - I don't have the cash for adjustable shocks now, and I have stock leafs in the rear and a stock M2 front end with unknown springs..... that will have to do for DW this year. It is what it is. I don't have a trans brake - will be foot braking it - so - it won't hit the tires anywhere near as hard as your car.

I have to modify the front spring pockets to allow the caltracs to rotate - I made the spring pockets longer than they needed to be in an attempt to match up the contour of the frame rail.... most of that will have to be trimmed away (or notched) to allow proper rotation.

[JeffMcKC]

That looks like a Post from my YB brother Jeffc or Jeff2 because he calls me Jeff1
The only thing I would say is,,,, Pushing down on the car is fine, but pulling up is the issue, Back and Front, because the axle is going to separate and resistance to that will be the issue, it likes to be easy and lots or travel to start with. Remember Jeffc wrote that for High HP cars (his has went 1.13) I would not be worrying about flipping over. LOL Good Luck!

[Joe Grippo]

No transbrake here either...footbrake only. I'll call you next week.

[TC]

Alright found the instruction for the Caltrac's for my truck, this is what it says.....

With Caltracs installed, reinstall the rear tires and lower the car to the ground. For an initial setting have the driver in the car, (or a similar amount of weight). Turn the Force Transfer Link 1/4 TURN evenly side to side to establish pre-load. Tighten the Force Transfer Link lock nut. That's it.

I think some of the stuff I said before was from an article I read, but this is the way the instructions say to set it up initially....... Not sure why you'd want a gap and allow the spring to twist, but I'm sure there's a reason for it........

[Barry Donovan]

Alright found the instruction for the Caltrac's for my truck, this is what it says.....


I think some of the stuff I said before was from an article I read, but this is the way the instructions say to set it up initially....... Not sure why you'd want a gap and allow the spring to twist, but I'm sure there's a reason for it........

the diagonal line from left rear to right front,
right rear to left front.

framed cars try to hide it, but time will show..a good floor pan all four corners, and bushings that squish. An allowance of twist in suspension is the real cure.
they used to play with those on regular cars here, needed rally type suspension just to go down the road.

the weirdest outcome was the dusters and the like, rip front of rear spring mounts right off the chassis. Did not see that again until 80s camaro tin canniness.

[Beagle]

very interesting thread John, and thanks HOOK AND PULL A HUGE WHEELIE guys for the responses...

[Joe Grippo]

very interesting thread John, and thanks HOOK AND PULL A HUGE WHEELIE guys for the responses...

9-10MUSCLEPALOOZADAN0009 by Joe Grippo, on Flickr

[CDMBill]

I found the YB thread very helpful and this distillation is helpful too.

[milner351]

I got my bars used but still in the box from a friend - the instructions.... not so much, thanks for the quote TC.

The instructions say to adjust each side evenly at ride height with driver (as Joe said he does) to establish pre-load - but they don't say how much pre-load to establish.

[TC]

I got my bars used but still in the box from a friend - the instructions.... not so much, thanks for the quote TC.

The instructions say to adjust each side evenly at ride height with driver (as Joe said he does) to establish pre-load - but they don't say how much pre-load to establish.

In the quote it says to use a "1/4 Turn" of pre-load, that is the starting point, then you can use what the OP said about fine tuning it...... Launch the vehicle if it pulls to one side add more pre-load to that side bar or vise versa if it pulls to the other side. I would probably just do hole shots until the car goes straight adding a 1/4 turn of pre-load at a time to which ever side it is pulling to.........

[Joe Grippo]

The only pre-load I use is my weight sitting in car. In my opinion, if you adjust the stop bolt evenly on both sides while your in the car the left side will have some defacto pre-load. How much exactly I don't know but I have never put in any extra and my car leaves straight and square.

[CDMBill]

Joe, I see you get a lot of rear separation. Have you played with slowing the extension on the back and if so to what result?