Wonderbread

iTrader: (51)

Here what I have and whats goin on:

98 Trans Am
- 347 making 450 RWHP NA
- 9" Rear 3.70 gear...spool
- Pinion angle -3
- MT ET Street Radials 325/50/15 (28") tall running between 16-19 PSI
- PTC 4000 Stall
- QA1 R Series in the front adjusted to 2 300lb springs
- QA1 12 ways in the back on 5
- Spohn 1" Weld In Drag Bar
- Spohn Rod Ended Control Arms
- Relo Brackets, Control Arms on bottom hole
- Stock Rear Springs
- Raceweight 3650
- Leaving at approx 3000-3200
- No spin


Best ET 11.42 @ 116 w 1.52 60'

It did that once.... its seems to run a 11.46 @ 116 w/ 1.59 60'

The thing is the car squats like a SOB. I wish I had some pics, but do not. What should I look at or change? Any suggestions? TYIA

fasttagurl

iTrader: (12)

Some items to look at would be taller gears, PSI in tires is too high, heavy car, and try launching at idle and you will see the 60" and overall times improve! I tested this theory and mine runs SLOWER when it is stalled up.

LT1-DAN

It's called weight transfer. You cannot get rid of it completely. You could always add wheelie bars.

omcar

iTrader: (10)

Go to 3 on the rear QA1s...

Wonderbread

iTrader: (51)

So getting rid of some of the weight in the front would help?

I have a friend with a procharged car with stock shocks, springs, just some LCA's a torque arm, stock sway bar and the car leaves nice and the body rolls over the rear wheels like it should. Not down on the wheels like my car does.

Harley-Davidson88

iTrader: (71)

You can transfer weight to the rear without compressing the rear suspension.




To the OP...what are the rear shocks set at?

Wonderbread

iTrader: (51)

Rears at 5 front are at 2

LT1-DAN

Hard to say, maybe your suspension is a little too soft. Do you have more lift in the front or more squat in the rear?

BOLO

iTrader: (40)

I don't know how your rear qa1's works with the adjustments, but I would adjust them a little firmer.

I run CE 3 way adj. shocks and have them set at (firm). Check out video below in my sig. Hope this help.

Wonderbread

iTrader: (51)

Alot of lift in the front, front tires just barely leaving the ground... if at all. From what I have been told the tailpipes (That stick out about an inch further than the bumper...still ahve to fix that) look like they are gonig to drag the ground when I launch.

Bitemark46

I think -3 pinion is too much with sold CA's. Should be -1.5 to -2. Stock springs... what is the rating on them? If the rear is squatting then the springs are too soft. -Mark

Wonderbread

iTrader: (51)

Honestly not sure on the spring rating. The main reason they are still in there is because that seems to work out for everyone else that I read about. Now the car does have 130k on the body.... is it possible they are just really wore out? If I have to replace these any recommendations on what I should use? Should I just look for a set from a lower millage vehicle? I have a place local that has tons of used Fbody parts so it would not be a huge deal to pickup a set. If there is something better after market, I'm listening.

Bitemark46

Oh I also forgot to ask you.. Do you have rim screws? Ever check and see if the tire is spinning on the rim? -Mark

Wonderbread

iTrader: (51)

Yes I did have the rims screwed. They did spin in the tire before, so I had that done at the beginning of this season.

Wonderbread

iTrader: (51)

One thing I didnt mention is that last season the car was pretty much resting on the Spohn torque arm because the wrong bolts holes were used to install it. Last year the car launched straight.

Now I fix the problem and the car squats.

It still would not 60' better than a 1.58 last year. 1.52 is my best this year.

Harley-Davidson88

iTrader: (71)

I would try some stiffer rear shock settings.

Wonderbread

iTrader: (51)

Im going to give that shot this weekend. If thats not it... anyone else have any ideas?

RAGENZ28

iTrader: (5)

If the car squats it's either the shocks are set too soft, you have the wrong springs (rate is too low) or your instant center is too low. First I would set the rear shocks firmer, one click at a time same on both sides. If you go up a few clicks and it still squats then I would try a heavier spring, for something around 3600 pounds I would think it will run a 175-200 pound rate.

If your torque arm is adjustable try raising the arm up one hole which should raise the intersection point which should add more anti squat. I like to see the car leave without it squatting at all or having a slight separation on the launch.

You can get a 10" coilover spring for the rear with an adjustable spring perch which is nice because you can also set the rear ride hight without cutting the spring.

Best way for help, post a video so we can see how it leaves then it's easier to offer advice.

JL ws-6

iTrader: (50)

Leave the air pressure alone, you're on a radial they like air pressure.

The car is pig heavy, so if anything, the air pressure is going to help it. Stiffen the rear shocks up to 6 or 7, see if that helps some.

Stock rear springs are fine, I've gone as good as 1.35 60 on them at 3500 lbs, so you're not really on the wrong spring.

I'm willnig to bet that if you could get a couple hundred lbs out of the car, really from anywhere you can at this point it's going to help alot.

Pro Stock John

iTrader: (34)

All I have are stock rear springs.

Run the rears at 7/7 stiff, that's what I run most of the time, and fronts at 1/1. Squat can be the rear shocks being too soft and the car rocks back.

Here's a bad squat pic of my car circa 2001: