2ktransam

iTrader: (12)

I recently pulled my trans to put a tighter converter in and now I'm having trouble hooking. I forgot to mark which hole I had the torque arm in the relocation bracket and now the car squats bad on launch. I'm sure the tighter converter is taking away some of the hit too but it was a must to run nitrous. All other settings are the same. Lca's, tires and shocks are set the same but the car is reacting completely different. I have the long BMR torque arm with the relocation mount. Which way do I need to go with the front of the torque arm?
I also just installed some Viking da rear shocks that will help some too. I used to 60' 1.41 on motor now the best I can get is 1.50 spraying 20' out.

Old converter

New converter

topgun542

iTrader: (6)

What was wrong with the new launch? does it spin with more power? Looked good to me.

2ktransam

iTrader: (12)

The new launch squats the rear hard and doesn't actually plant the tires. If you watch the wheel it is spinning just enough to drop the nose and unload the rear. The old launch hit the tires and was up and out smoothly. Now the car rotates back compressing the springs and wastes all of the forward energy. If I spray off the line it spins all the way through 1st gear.

z28a4

iTrader: (1)

Move the torque arm up, tighten compression and loosen the extension.

93camaro_zzz

iTrader: (13)

^ What he said, move the torque arm up.

jblankenship

iTrader: (5)

If you move the torque arm up it will lower the back of the car. This will cause less angle on the rear control arms. You need to measure the angles of the rear control arms. My guess is you need to move the torque arm down. This will raise the rear and may give you back the correct angle on the lower control arms. The torque arm is not the problem.

z28a4

iTrader: (1)

Can you elaborate? I've never noticed my rear ride height to change because of adjusting the torque arm, never paid attention though either. Not saying your wrong, I just can't visualize it. I am however planning on playing with it at the track tomorrow. Maybe I'll take a tape and do some before and after measuring.

Rob

BMR Sales2

iTrader: (40)

Changing the torque arm mounting position will not change ride height of the car. It only changes the instant center/lift point of the car which induces squat or anti-squat. Granted, Torque arms are a little different than this, but these illustrate how instant center and such is figured and its effects

jblankenship

iTrader: (5)

That picture is 100% incorrect for a torque arm car. Changing the torque arm location on the front will absolutley effect ride height. Especially, if you don't reset the correct pinion angle. Hell, setting the pinion at the adjuster will effect the rear ride height. It rotates the axle housing up or down when you adjust the torque arm. The only way to move the instant center is to shorten or lengthen the torque arm or adjust the lower control arms.

jblankenship

iTrader: (5)

What is the motor combo, how much nitrous,spraying out the hole, weight of car, trans, rear gear,, etc...?

Trying to get it work on motor is pointless if your goal is to spray the car. Mine will move around on motor on the 2-3 shift because there is not enough power to keep the rear planted compared to spraying the car it is 100% stable.

Do you have adjustable control arm mounts? What hole are they in? Are you on a radial?

I can help you get it close.

BMR Sales2

iTrader: (40)

I am sorry to say, but the only correct information in this post is the fact that the picture is not a 100% accurate representation of a torque arm, as I prefaced when I posted it. It still is an accurate representation of how instant center affects anti-squat and such.

z28a4

iTrader: (1)

Just moved my torque. No ride height change.

jblankenship

iTrader: (5)

Please explain how moving the front of the torque arm up or down could not effect ride height when it rotates the axle housing and the spring perches are on the back of the axle tubes?

So do you move the torque arm up or down for more anti squat?

You guys come in here with a picture of a 4 link car which is not how a torque arm car works. The torque arm does not push the car, only the lower control arms. The torque arm only effects instant center based on length of the torque arm.

The lower control arms are what effect antisquat.

His problem could be pinion angle crossing the centerline of the ujoint on launch. Especially if the torque arm was put back in the wrong spot.

I've gone back and forth on here with you guys before about pinion angle, because forever ya'll had people setting drive line angle from the drive shaft.

So, what should he do to correct the problem? Because, moving the torque arm up and down is not going to fix it, unless the small amount of ride height change from the torque arm corrects the lower control arms.

SoFla01SSLookinstok

I don't believe in the front tq arm mount changing ride height. Heck, change the front location & just adjust the rear so it's where it was. Some people change the front location & have no change. Some see slight changes.

I really cant add much for the problem. It does seem to squat a bit more. But now with the tighter converter you have different tq hitting the rear wheels. What about maybe spraying earlier? You also have the new shocks to play with.

jblankenship

iTrader: (5)

He doesn't know where it was. If you move the front and don't reset your pinion angle it will slightly change rear ride height. You'll notice below that I talk about centering the rear wheels in the wheel well. Guess why? Because, when you use the rear of the torque arm to adjust pinion angle it moves on a axis, which will effect ride height and the location of the rear in the wheel well.

Everytime I have set the rear suspension up I start by unhooking one side of the anti-rollbar. Put someone or something in the driver seat to simulate driver weight. Set the driveline angle, center the rear wheels in the wheel wells(square the rear), next set the rear control arm angle, and lastly reconnect the anti-rollbar set neutral. Then adjust shocks at the track. FWIW my rear vikings are at 5 extension and 15 compression. Best 60' 1.36 at 3700 lbs.

Shocks don't effect antisquat. They only control the rate.

SoFla01SSLookinstok

I don't want to start a war man. If his TA wasn't already adjust for proper pinion angle should just use that as a guide to find where it was. I actually agree with your posts. Except the ride height change. How much change are you talking? .007"?

Sounds like a good process. Nice time.

I never said they did. So say he gets it back in the same location & it is the same? Friendly discussion.

jblankenship

iTrader: (5)

The problem with squatting is nothing more than a lower control arm adjustment. The rear of the lower control arms need to be moved lower.

Good read: http://www.yellowbullet.com/forum/sh...d.php?t=506618

SoFla01SSLookinstok

That is a good sticky. So IF all he really needed was more AS, & his LCA's were already set to the lowest spot, I guess the next step would be the shorter TA.

jblankenship

iTrader: (5)

No, the next step would be to either raise the car up some or longer relocation brackets. The shorter torque arm just hits the tire.

2ktransam

iTrader: (12)

So it finally stopped raining long enough to go test some more. I tried spraying off the line this time and nothing I tried would keep it from lighting up the tires. To answer some questions I am at stock ride height with LCA relocation brackets. Lca's are in the bottom hole which is 3* up hill towards the front of the car. I moved the torque arm up two holes from center and adjusted the shocks all over the place. I'm at a loss at this point.
No matter what I tried it would hook and lift the tires a couple of inches and then light the tires up. I had the rear shocks pretty tight and started to get some separation in the rear but it's just wouldn't hold the power. I'm sure some of my issue is a crappy track but I think the car should hook at only 700rwhp.