Drag Racing Tech - Suspension tuning help needed.

I am slowly turning the wick up on my ride in sig. The problem is I am getting closer and closer to putting her on the bumper. I have the front end tied down and the front shocks pretty tight and pulling 1.40 60's, but I am pushing the envelope.

My question is: Is binding the front end down the best way?
It seems to me, the most efficient way would have the car leaving forward instead of up, and I shouldn't need to tie the front so tight.
But how is this accomplished, by torque arm position or lower control arm position?
I am sure it is a combination of both, but which would have the most effect, or where would you start..

I understand that this is a complicated question and will be difficult if impossible to answer. But I am sure some have figured this out, so no use in re-inventing the wheel..

Current setup includes Qa1 single adj. up front. BMR torque arm, Comp Engineering drag shocks out back with stock rear springs.
Thanks,
Rick

torque arm position or lower control arm position?


What are there current positions?
Short or long torque arm?

What are there current positions?
Short or long torque arm?

It is the BMR short torque arm, and is not adjustable as is. The rear is a Moser 9" and does not have adjustable lower control arm mounts as is.
But, that is why I am asking. I can modify the torque arm mount and the lower control mount. But would like to know which way I need to go.

I think it really depends on the power level of the car and in your case I'd say no. If your really tight on the adjustment and having trouble controlling the front end you could run a slightly heavier spring up front. I'd start with 25 pounds heavier then it should put you in the middle of your adjustment and allow for better control. As far as the torque arm goes I'd keep it the same until you can get better control of the front end. However, I would make sure the control arms are at least level. I have 6 different length torque arms and have swapped from the smallest to the largest and still put the car on the bumper. It's a mount that was made for testing torque arms. http://i46.tinypic.com/w7n76.jpg

I think it really depends on the power level of the car and in your case I'd say no. If your really tight on the adjustment and having trouble controlling the front end you could run a slightly heavier spring up front. I'd start with 25 pounds heavier then it should put you in the middle of your adjustment and allow for better control. As far as the torque arm goes I'd keep it the same until you can get better control of the front end. However, I would make sure the control arms are at least level. I have 6 different length torque arms and have swapped from the smallest to the largest and still put the car on the bumper. It's a mount that was made for testing torque arms. http://i46.tinypic.com/w7n76.jpg

Wouldn't that mount make all of the torque arms the same length due to one mounting location on the chassis?

Wouldn't that mount make all of the torque arms the same length due to one mounting location on the chassis?

No, there are six different mounting points along that piece. Look between the large circles cut out and you can see the 6 mounting points with 9 holes of adjustment. The longest is 50+ inches while the shortest is 20+ so they are not the same length.

No, there are six different mounting points along that piece. Look between the large circles cut out and you can see the 6 mounting points with 9 holes of adjustment. The longest is 50+ inches while the shortest is 20+ so they are not the same length.

I think it is a cool piece. The effective Z Vector off the end of the TA is dependent on where the end of the TA attaches to the chassis since it is not a fixed link.

It looks like the adjustable mount has 2 fixed chassis mounting points. One x member near the trans and one near that short TA. That will effect the actual location of the Z Vector unless that multi piece is continuously welded to the bottom of the chassis.

A short TA that mounts at the back of the piece "should" have an effective length at the back x member.

A long TA that mounts at the front of the piece "should" have an effective length at the front x member.

Anything in between would be an interesting math equation.

I think it is a cool piece. The effective Z Vector off the end of the TA is dependent on where the end of the TA attaches to the chassis since it is not a fixed link.

It looks like the adjustable mount has 2 fixed chassis mounting points. One x member near the trans and one near that short TA. That will effect the actual location of the Z Vector unless that multi piece is continuously welded to the bottom of the chassis.

A short TA that mounts at the back of the piece "should" have an effective length at the back x member.

A long TA that mounts at the front of the piece "should" have an effective length at the front x member.

Anything in between would be an interesting math equation.

The piece is mounted in between the front and rear bars and that's what the torque arm actually mounts on. That gives me 6 fixed chassis mounting points which requires 6 different length torque arms. I have tried every one and the only real world difference I have seen is the longer one seems to go down the track smoother and be slightly less aggressive off of the line.

The piece is mounted in between the front and rear bars and that's what the torque arm actually mounts on. That gives me 6 fixed chassis mounting points which requires 6 different length torque arms. I have tried every one and the only real world difference I have seen is the longer one seems to go down the track smoother and be slightly less aggressive off of the line.

Here's the picture with the 6 chassis points highlighted. http://i46.tinypic.com/2912sl1.jpg

[QUOTE=TurboStangJON;16640865]Here's the picture with the 6 chassis points highlighted. http://i46.tinypic.com/2912sl1.jpg[/QUOTE


Cool piece. But IMHO it is only valid for long and short TA's due to the mount locations. A mid length TA may mount in the center of the piece, but it will not give a Z Vector in the center of the piece due to how it is mounted to the chassis. (Unless you used a fixed end TA instead of a slider link)

I have seen this design on another car built by a well respected chassis shop. It doesnt work. The length of the arm isnt relative in this configuration. You also have to figure in height. Moving the arm fore and aft doesnt do anything unless you can move height.

I have seen this design on another car built by a well respected chassis shop. It doesnt work. The length of the arm isnt relative in this configuration. You also have to figure in height. Moving the arm fore and aft doesnt do anything unless you can move height.

The height can be moved but only 3-4 inches. Didn't have any more room in the tunnel at the time.

You would have to weld a x member at each red circle in the pic for it to transfer the Z Vector at the end of the TA to that point with a slider end. (Or continuously weld the entire length).