body roll

[hasben]

Our car will not roll over as much as it should. We have checked ride heights, j-bar has 5" of rake. Car has Q/C and jbar located appx 1 " below pinion. Shocks are not binding nor birdcages - what are some additional areas to check?

[js11]

What kind of rear suspension, front clip, springs, etc are you working with?

[johnny v]

Tear drop tank or regular rectangle or Square? Alcohol or gas?......... RR spring?

I am right in the middle of a winter refurbish on a 09 harris , pulling a 32gal tear drop cell and putting in a 16gal rectangular cell..... previous owner ran on alky, we are on gas.... we are only putting in 8 to 12 gal of gas..... Weight way down low in the tear drop.....

Going to raise the CG..... been looking at lots of cars.... probably put the bottom of the cell 2" below main frame rail ( looking at it from the rear)..... might even make a couple of sets of mounts to raise or lower it easily .....

[hasben]

Johnny you know the car. 4bar chevelle clip kk704 tires

[hasben]

springs 650/600 front and 200/225 rear. i think - book not here

[johnny v]

Johnny you know the car. 4bar chevelle clip kk704 tires

I'm old and forgetful, refresh all our memories with details...

[js11]

I'm assuming you're running the spring behind on the LR.

For what it's worth...

My experience has been that if the car is not binding though suspension parts, the slip yoke at the tranny or through the shocks, you might have too stiff of a RR spring, or too still a RF spring, or both. You don't want to go too soft at the RR corner though, because that will decrease side-bite...even if you do increase body roll. You can also hang ballast high and to the RR side of the chassis to help things along (above and just behind the tire).

Further to that point, if you already have the softer spring on the RF, and the 225 is on the RR, try putting the 200 on the RR ( I would also run a 200 or 175 on the LR). Also, make sure your LR shock is not topping out. All this assumes you have the correct offset on the QC, and that you've strung the car to make sure things are square-up.

Also from past experience, I'm thinking that 5" static rake (and 1" lower than the QC pinion at the QC plate) is a bit too much. I've often found that too much rake at the J-bar makes corner exit too skaty and erratic. Try 4' from static, and a little higher than the yoke at the QC. Then lower both ends if you feel you need to lower the RC.

...Just my immediate thoughts on the question. Good luck.

[hasben]

johnnyv you are on target with the fuel cell. When you set that little cell, mount it as close to the decking as you can.

Our fuel cell is rectangular.

We have been having trouble with the rear seal and thought it was possibly the yoke bottoming out. We cannot duplicate that in the shop. That is one of the things we have checked. We have debated about decreasing the angle in the jbar. In fact upon checking we have 6.5" of rake. That could be some of our problem. But the chassis mfr recommended that setting on the rear end.

[js11]

If your damaging the rear seal of the tranny, then that is not helping. It could very well be affecting the other aspects of the suspension. I would try to get at least 2.5" of barrel sticking out the the back of the transmission seal, and at about 2" in (that's assuming it's a Bert or some other aftermarket tranny). I have experienced this in the past. Once I ironed that out, it was amazing the difference in how the car responded.

I don't know how you are simulating this in the shop, but on the track there is a lot of movement that can be hard to replicate in the shop. If you go on Youtube you can find some Mods with suspension camera footage that will be very helpful to see.

[hasben]

we have about 2" of the yoke in the transmission at ride height. It is the long yoke. Transmission is only 3 years old and will accept long yoke. Only getting about 1 1/2 " travel on pull bar. It is a new yoke and not distorted.

[oldtrackchamp4x]

Is the car getting on the RF? How much shock travel do you have left on RF? If there is over 3/4 to 1 in left i would soften the RF spring to 500-525 and LF to 550-575. Can also add lead up high on RR side over rear end. Also agree with js11 on changing rear springs. Works for me. JMO

[HEAVY DUTY]

I have not seen the LR drop mentioned. If the LR tops out too quick, it will keep the car from getting on the right side. Too much causes worse problems though.

[hasben]

we have chain limiter on car which stops roll before topping out lr shock. We have even put a 2" extention on shock and lengthened chain. No change in rf travel still 1 1/2" to 2". Cannot find any binds in shocks or birdcages.

[HEAVY DUTY]

we have chain limiter on car which stops roll before topping out lr shock. We have even put a 2" extention on shock and lengthened chain. No change in rf travel still 1 1/2" to 2". Cannot find any binds in shocks or birdcages.

How much does it drop? 4 to 4 1/2 " from ride height to chain tight is about right. Different ways to measure changes it a little. I would measure with all 4 wheels on ground and jack up under seat to simulate roll. Measure between thecaliper brkt and bircage straight up to the deck. That or the Center of gravity height. If they are ok, you have a front end geometry problem ( too much antidive)

[hasben]

we measure from bottom of top overrail to top of top of axle tube and it measures 4.25" from ride height to full travel that is allowed. we run usra kk704

[JustAddDirt]

we measure from bottom of top overrail to top of top of axle tube and it measures 4.25" from ride height to full travel that is allowed. we run usra kk704

Depending on how far in the framerail away from tire, that could be 6" of drop at the contact patch of tire. May be too much.
just an observation.

[thfleshman]

if the car is not rolling over (assuming all binding issues if any) are fixed in suspension get a long yoke and try to bury it in the trans we had issues and the yoke actually was binding on the shaft(not the housing) because the yoke was hitting the shaft where the output shaft splines ended. we took the output shaft out and had it relief cut about .010 and its perfectly fine now. I believe the new trans may even be doing this from factory now?? thats just hear say

[hasben]

we have checked the yoke travel into the transmission. No problems.

[JustAddDirt]

If you are on a 225 on the RR with a KK 704 tire you may be too stiff depending on tracks ran. I run UMP tires, and that 225 RR spring works well on our tires. But we have a softer sidewall.
What are your shock valvings?
If you have some stiff valving, or alot of low speed in the RF you may need to soften the RF spring 50# at a time till you get some movment. 1.5-2" is not alot of travel. Are you on a bumpstop on the RF?
Chassis roll, or hike does not always promote forward traction or sidebite.
What is the car doing, or doing wrong?
Is it skating across track on entry or through middle?
No forward traction?

[MM90]

Body roll doens't create sidebite, sidebite creates body roll.