Caltracs - install, set up, tuning

[CDMBill]

On the front shocks the DA BNC Afco's are the hot ticket at moderate prices. They have valving to control bounce hence the 'BNC' and you can slow down the front if that becomes neccessary with the extension tuning. Santhuff are top of the line as are JR1, and I hear good things about the Strange parts but have not run them.

On the back, going to the upper hole will make the hit more violent and will escalate the need for a DA shock to control extension as Jeff mentions. You'll get ET improvements if you can get the car to launch forward rather than upward, but its not as impressive. Small tire cars do seem to benefit form the height sometimes as the time at 100% weight transfer covers the torque multiplication peak 20-30 ft. out.

The open tracker roller perches will free up the front suspension adding to your speed of roatation on the launch, e.g. bigger wheelies absent adding control via the shocks.

[CDMBill]

Treed by Jeff.

[TC]

I will soften the rear shocks first and that doesn't do it I guess I will move to the to the top hole in the Caltracs.

I'm not sure if moving to the top hole is the right way to go..., on the ladder bars on my '71 Camaro I have 3 mounting holes for the front mount for the ladder bars, the way it was explained to me is to run the ladder bars in the top hole, but if I pull the wheels to much that I need to drop it down a hole and if I still pull the wheels after I get to the lowest hole then I need to go back and see the guy to have wheelie bars put on....... I would assume the Cal-tracs work the same way, so moving to the top hole on the cal-tracs, might make you wheelie even more/easier........

[JeffMcKC]

They do not work the same way, and your ladder bars don't work that way either.

Ladder bars holes are all above 100% anti squat, the more seperation you require to plant the tire the higher hole you might use. Wheelies have little to do with seperation and should not be treated like they do.

[TC]

They do not work the same way, and your ladder bars don't work that way either.

Ladder bars holes are all above 100% anti squat, the more seperation you require to plant the tire the higher hole you might use. Wheelies have little to do with seperation and should not be treated like they do.

That is just how the guy that tubbed my car explained it to me about which hole to put the front mount of the ladder bars in...... I think it has to do with instant centers....., he did say the top hole was the optimum hole to run it in, but like he said if I pull the wheels to high, that I can drop it to the next hole down to combat pulling the wheels to high....... But then he builds Prostock chassis's, so I'm sure he doesn't know what he's talking about..........

As for the cal tracs and which hole to run it in, that is a phone call away, as Calvert with each kit recommends which hole to run it in, like with the one's for my GMC they recommend the bottom hole.......

[JeffMcKC]

Sure he does TC, Maybe in 1972. There is not a Pro Stock running a Ladder bar. If he did build them there is no way he made such a stupid statement as that. A high HP car with ( depending on how high the top hole is) will not drive well on the Top end and will drive the wheel into the pavement. You should ask him again, this is another case of you not knowing for yourself but blind following a incorrect statement thats easly proved false.

[CDMBill]

Since this is a Cal-trac thread I'll relate some information I received at Pomona last Weekend. John Calvert was there along with several of their race cars running their equipment of course. I ran my current set-up by them to see what I might be leaving on the table and the big distinction that emerged and that often gets lost in translation is whether some one is running bias ply slicks or drag radials or radial slicks each of which requires a different approach, especially when it comes to shock settings.

Most of the information out there is for bias ply slicks and the key difference is the extension or 'rebound' setting, at or close to full stiff for drag radials, far softer for bias ply's but in either case starting from the baseline layed out at the beginning of the thread and following the directions from there will get some one from baseline to an effcient launch pretty quickly.

[TC]

You should ask him again, this is another case of you not knowing for yourself but blind following a incorrect statement thats easly proved false.

It's not that I don't know, it's what I was told, thing is you don't know how he set the suspension up to begin with, so not knowing that, how can you make a blanket statement about what it will do?? Like you said, "depending on how high the top hole is", well lets just say the top hole isn't high enough to cause the problems you are describing......Lets say the top hole is the optimum position to have it in........

I guess the question is Jeff, what do you do on a ladder bar car if it pulls sky high wheelies and adjusting the shocks doesn't keep it from doing it.........

[JeffMcKC]

I would aim for 100% anti squat to start with on a bias tire ( no rise or squat from the rear) or as close as you can with the mounts you used, or on a radial 120%.

There are sevearl things, but as said before, you need to seperate the wheelie from the ladder bar settings. First a Wheelie is a Lack of Power for the way the chassis is set up. ( Drag Radials differ) The tire on a Bias tire should not be dead hooked, if it is dead hooked on a bias or radial then it becomes easier for the pinion to climb the ring gear than to move the tire, We then have a wheelie. To know a wheelie out you can first try to pick the unsprung wheight of the front up quicker, by tightening the ext of the front shocks to work as a limiter. Then you could also use a limiter, but that might be harsh and shock the tire into spin not slip. You could move weight forwards. You could change 1st Gear ratio on a Bias to a lower gear to gain tire speed, on a radial tire take away mech gear so it does not have leverage to climb and will loosen the converter at the same time, add power, add air to the rear tires. Tighten the rear shocks on ext to limit the ext. , lower the rear of the car.

TC none of this is touching the ladder bar position, because the ladder bar position on a ladder bar car is a huge change, minor changes are done with ride hieght.

You want as little of anti squat/Percent of rise/Rear axle seperation as you can, and still plant the tire. (read this as wasted motion and energy) Making changes for wheelies are just not done in this area, unless you have totally missed the set up to start with, and your trying to kill way more seperation than you need, to get the tire to slip, but your correcting the seperation issue, not a wheelie issue by doing that.

As Bill said Drag Radials are a different animal.