I hope the "Phantom" will get some looks to this post.

I have a highly modified 3rd Gen. The trans is a T-10.

Stock Trans mont gone. Replace with a 2 X 3 square tubing mounted to home made frame rails / sub fram connectors.

Torque arm is now attached to the trans mount / cross member. Arm is mounted north of trans mount and will pull under accelaration.

Arm is attached via a very short 4 link tube with hiems at each end to adjust pinion angle.

My question is...

Due to the fact that both attachment points can pivot, how will this effect the car in transition from accelertaion to braking?

Under braking the arm will push town on the cross member but since the link can piviot at both end it may be like trying to push a string.

Will the rear end move fore and aft?

Hope to have the car on the track by Feb. I can refab the unit so that it will be fixed on one end if needed.

Please comment.

 

I'm sorry but I cannot visualize it for some reason. Can you post a picture? What did you mean to say when you said the connection is made " north " of the crossmember mount? How is the torque arm a four-link?

You've fabricated and installed this already? ...and you are only just now asking the question of how will it affect your acceleration / braking? I dont understand this. I'd like to help but need more description, especially on the issue of how the crossmember end is hooked up.

 

Thanks for the response.

I am not computer savey enought to draw you a computer picture.

Parts are made and have been installed out now painting chasssis

So try to see this.

<-front rear->
-0--------------------------------- torque arm
I
I
0
( ) trans mount

The front end of the arm is located next to the trans like stock, but mounts to the cross member instead. The cross member is below the torque arm. Look at the above pic. the "0" represent the hiem joint. The I represent the hollow bar that the hiem screws into. the hollow bar is short with hiem on each end. heims mount into bracket on cross member and torque arm. Torque arm is a modified stock unit that the front portion being modified. ie. shorted and boxed with a forward facing bracket to mount the heim.

Under acceleration the arm will lift the the link which will pull on the cross member.

Let me know if this helps.

Thanks for the interest.

 

If I understand the drawing I don’t seen an issue, but I also don’t see a reason to make the link length adjustable, it will have almost no effect on instant center.

 

Thanks for the help

It is adjustable because the hiems screw in. So no reason to make it non adjustable. No need to weld them in yet.

may need some slight tweeking at some point.

Glad that you do not see any issues.

Thanks for the help.

 

If I'm understanding it correct, it sounds kinda like a spohn unit with more heim joints?

 

Your axle is restricted by the lower control arms from moving fore/aft. As the axle moves up and down as suspension compresses and rebounds, the torque arm heim joint mounting point will move forward and backward with very little resistance due to the heims. That's a good thing. The bad thing is that as the link swings fore/aft, it does so in an arc, effectively lengthening and shortening the heim jointed link as your suspension travels up and down.

Luckily it's only a very small amount. As rear suspension unloads on hard braking, the torque arm pulls backward, and the heim joint essentially shortens, moving the mounting point downwards. Instant center will shift rearwards a small amount. I can't say how much without laying out YOUR suspension dimensions on paper and doing YOUR math for you...

Same thing for hard acceleration: The car squats on the rear springs, and the heim slides forward on the arc, again effetively shortening its length. Instant center again creeps rearward a few inches. I can't say for sure how much for the same reason: Your suspension geometry is unique to your car. You will need to know how long your heim jointed link is, and how much suspension travel you are getting on hard acceleration and braking in order to compute the exact amount of change you are getting on instant center.

A good picture of torque arm instant center is shown on this page from unbalanced engineering: http://www.unbalancedengineering.com/Camaro/TA/

By adjusting the distance between the heims you will get a very small amount of pinion adjustment, but it will be small. You can calculate it if you want using this formula:

Angle of adjustment = Arctangent ( Total travel of heim joint adjustment / (torque arm length+distance to axle centerline)).

Doing some quickie calculations with a guesstimate of 36 inches for the torque arm + differential to axle, and a one-inch adjustment range, I get something like 1.5 degrees of total pinion adjustment range.

As for transition between acceleration and braking, I suspect that you will see negligble difference in i.c. for the two. You have in essence created a stock torque arm with a small amount of pinion adjustment. It should work like a stock torque arm just hopefully be a bit stiffer.

Watch the heim joints: I hope they are Aurora ot QA1 extreme duty versions, because automotive use is very hard on them. They wear quickly unless you have teflon races in the heim joint. Regular old heims have a live expectancy of only a few thousand miles before they loosen up and rattle.

Good luck!

 

Thanks WS6

I will try to do the math when I put thing back together.

I just wanted to make sure that it would not do anything crazy.

As for Dean, I miss his posts.

Maybe he should come up with a new user name like Bo Duke or something that did not include V6 in the name and keep a low profile make a few generic posts and blend back in.

Thanks for all the help.

 

I'd like to see some pics of this setup. I'm still kinda lost on what your saying.

 

Ede is a piece of sh*t.

If they are going to erase my good informative posts, I might as well post some crap and make their job worthwhile- bringing it upon yourself EDE
Merry fukken Christmas.