Darn.

One thing I think of is "when is a shorter torque arm needed"? Is there some sort of guide line? I think all of the serious f-bodys I see, that can drag the bumper, have the shorter torque arm.

Your setup, the way it is, may not even be much more than 100% AS. With everything else the same the shorter TA will raise this value.

 

This is a drawing I generated when setting up my car.

 

I've always heard that a long torque arm is better for high horsepower. Not sure if that's true though. I'm going to move my torque arm back down this weekend and move the lca's up to the middle hole. I think the 200 shot might be too much for this crappy track all at once.

 

I think I've heard that also. But I think it refers to much higher hp & maybe a bigger tire? I really don't know either. I guess the best thing is keep testing & taking notes. You may also be right with the instant 200 shot. What about a nitrous controller to ramp the spray?

 

Have you scaled the car? The front shocks may be rising to to fast.

 

I'm running in two street classes and one of them doesn't allow a progressive controller. I might put one on for next year and just use it as a window switch for that class.

 

I have not scaled the car yet. I need to find someone local that can do it. I have the front pretty tight. If I go any tighter on the front shocks it spins off the line. The front shocks are set on 7 and if I go to 8 it spins before it starts lifting the nose.

 

Once you get the car on the scales, you may be shocked what you see.

Before:
Best I could before adding weight.



After:



This was with 8 gallons of fuel, 200lbs in drivers seat and 60lbs. added to right rear. Noticed front spring lengths are almost identical at adjusted length. Same with rear, which was almost and 1" difference. Will be fine tuning weight balance to get it right on this winter to get it right on.



Will not be able to get to the track till next year. After the balancing, and taking some test hits on the back road, noticed the the frontend rise is not as prominent and the car has more of a frog like motion.

 

From what I have seen on my car with the long torque arm, not as much power. Raising the torque arm plants the tires harder at the initial hit, but they come unplanted faster. Lowering it doesn't hit the tires as hard, but they stay planted. So for my car, I use a lower mounting point, because the 6 speed crushes the tires on the hit either way. I need it to stay planted longer. But I'm still not in the bottom hole of the bmr relocation bracket either. My lca's are in the bottom hole, approx 3 degrees downhill to the rear. Doesn't separate or squat where it is set.

What are your front shock settings? It could also be that you need to tighten front compression

 

Front shocks are single adjustable set to 6-8 depending on the track. I moved the torque arm back down to one hole below center. That's as low as my exhaust will let me go. I set the pinion angle to -2* and moved the lca's to the middle hole which is level. I loosened up the rear shocks and foot braked the car and got good separation which is an improvement. I'm going to try that this weekend and get the car scaled before the next event.

 

If you are stock height with relocation brackets and in the bottom hole I can guarantee that you are hitting the tires too hard. You are driving them down and they are bouncing back up like basketballs. You are making the right move moving them up a hole.

 

I also believe when you measure the angle of the lower control arms you should take the measurement compared to the chassis. If you are measuring 3 degrees but the car has a rake they could be 5 degrees running downhill compared to the chassis.

 

I hope you are right. That's what it looked like in the videos from last weekend. On motor it was working great, 1.41 60' normally. I think the 200shot is too much for the lower holes.

 

This is stock front suspension with oem 150,000 mile shocks, intrax lowering springs, swaybar removed.

Rear is lower control arms at 1.5 degrees down compared to the chassis, bmr xtreme anti rollbar, cut stock springs, viking shocks at c=15, r=5, -2 degrees pinion angle, long BMR torque arm as low as the front will go.

275/60/15 Pro, 20 psi, leaving on 250, 3.70 rear gear.

 

The chassis is 2* downhill and the lca's are level. When I foot brake the car they go uphill 2* from the chassis lifting.

 

This on motor with the Na converter. The car was working good then.

 

Does it come back down real fast? If you are hitting the tire hard enough on motor to lift the front that much you are probably killing the tire on spray. I bet it leaves fine with the control arms moved up.

 

I actually set a jack under the front end to zero out the chassis and make suspension adjustments easier. But yes you definitely have to take the rake into consideration if you don't zero it out like i do.

I also agree that the middle hole on the lca's is better if you are stock height. Mine is about an inch lowered.

 

The tighter converter only pulls the tires about 2" on motor and sets it back down quick. The spray comes on at 3k which is about 2 tenths of a second after wot. It gets all kinds of stupid and drops the nose really fast.

 

You may need to lower the window switch so your not hitting the tires twice. Just went through the same thing.