Chevelle Suspension Help!!

[Ovrnightr]

I have a suspension problem with my 69 Chevelle I was hoping you could help me with. The car twists quite a bit off the line which causes the 60’ times to be slow and inconsistent. On a good track it lifts the driver side front wheel about 2’, the passenger side 1’. The passenger rear dips about 5” – 7”. The best 60’ is 1.635. The average 60’ is 1.675 – 1.725. On a marginal track the 60’ averages high 1.70’ to low 1.8’s with some tire spin.

Car details:

-Competition engineering 3 way adjustable shocks. Front set : 90 – 10 Back set: 50 – 50
-Moroso Drag springs. Front 47160 Back 47500
-Hotchkis upper (adjustable) and lower control arms.
-Moser 12 bolt rear end (with the raised upper control arm mounting location) 4:56 gears. Pinion angle set 2 – 2.5 negative degrees.
-29” x 11.5” Hoosier Quick time pro tires @ 9 psi.
-Turbo 400 transmission with a trans-brake. Launch RPM 4800 on the rev limiter. The converter will stall to 5200.
-Car weighs 3300 LB with driver.
-Engine has ~600 HP at the fly wheel, ~470 at the wheels. (Dyno tested)


What can be done to increase the 60’ times and straighten out the launch?

[Ed-vancedEngines]

This application is one of the few applications where I feel that adjusting a pre-load with an anti-roll bar is beneficial. Because of your triangulated rear upper control arms you can not adsjust your bars with any pre-load adjustment.

I suggest to get a good high quality anti-roll bar from Wolfe Racecraft-Jerry Bickel-Rick Jones etc. I stay away from the lower priced anti-roll bars because they do break parts and can cause serious handing problems during a launch. You can add a spring spacer onthe right rear and the left front to also help some.

IF you could move the front of bottom bars downward below a neutral level position and also move the front of the top bars downward the same amount or maybe even a little further I think you would see most of that Barrel Roll disappear too.

With the basic stock chevelle suspension though use a good anti-roll bar and set some pre-load in it gradually increasing it as you feel it out. Too much pre-load the car will want to go left.

With a chevelle I also suggest to lower the rear ride height as much as possible without hitting frame or bottoming shocks too.
Ed

[SSEA]

Here you can get moore info http://www.chevelles.com/forums/forumdi ... 88ae8&f=13

[awesomebill]

I have a suspension problem with my 69 Chevelle I was hoping you could help me with. The car twists quite a bit off the line which causes the 60’ times to be slow and inconsistent. On a good track it lifts the driver side front wheel about 2’, the passenger side 1’. The passenger rear dips about 5” – 7”. The best 60’ is 1.635. The average 60’ is 1.675 – 1.725. On a marginal track the 60’ averages high 1.70’ to low 1.8’s with some tire spin.

Car details:

-Competition engineering 3 way adjustable shocks. Front set : 90 – 10 Back set: 50 – 50
-Moroso Drag springs. Front 47160 Back 47500
-Hotchkis upper (adjustable) and lower control arms.
-Moser 12 bolt rear end (with the raised upper control arm mounting location) 4:56 gears. Pinion angle set 2 – 2.5 negative degrees.
-29” x 11.5” Hoosier Quick time pro tires @ 9 psi.
-Turbo 400 transmission with a trans-brake. Launch RPM 4800 on the rev limiter. The converter will stall to 5200.
-Car weighs 3300 LB with driver.
-Engine has ~600 HP at the fly wheel, ~470 at the wheels. (Dyno tested)


What can be done to increase the 60’ times and straighten out the launch?

I run a 68 Chevelle for a couple of years with stock suspension like yours. Left straight as an arrow and would drag the bumper. Heres what I run. 3900 lbs wme in it, 454 th350 9" convertor 4.10 gear. I had the front and rear sway bars, good ones, full exhaust and drove it everywhere. I decided to loose some weight and pulled the front and rear sway bars off, took it to the track and had a Mister Twister. Car rolled over just like the Chevelles do. This roll effect is only caused by the engines ability to kill the right rear, passenger side, spring. With both front and back sway bars, this kept the car from twisting. Actually they are what is called now, ANTI-ROLL BARS. They have been around for years. I reinstalled the front and back bars and the car went right back to dead straight. I also had a right rear air bag with 60 PSI. Just a front H/D bar will help the twist a lot. The reason the r/r of the car is allowed to go so low is because the r/r spring is being collasped and the r/r rear tire is being lifted off the track. That is why a really good rear sway bar eliminates this systom. Try it, or at least look into it. Also, the more engine you got, the worst the roll will become and the car will start to vere to the right really bad.

[Milan..]

You will need a roll bar , Wolf racecraft is a good one , Hr partsnstuff is good to for a bolt on. And a pair of at least single or double adj.(pricy) rear shocks to control the hit. Also a full tank of full and some ballast helps too. Check my cardomain...Thanks Milan..

[beth]

An air bag in the right rear will have you fixed in a couple of passes adjusting the pressure. Lots lighter than sway bars.

[awesomebill]

An air bag in the right rear will have you fixed in a couple of passes adjusting the pressure. Lots lighter than sway bars.

For the added stability on the gas and off the gas, the trade off is minimal in e.t. because this is static weight, not rotational. The e.t. will be much better and will cut down on the abuse of the left axle and body twist. Your car will launch better and you will be able to hit it much harder with little to none body roll. The air bag is o.k. and works fine but get running faster, or over 150 mph and watch what happens when you let off the gas. The right rear tire will be loaded way more and could lock up and could cause a mess. What goes fast must slow down faster if you don't have a chute.

[TORQUE INC]

the HRpartsnstuff bar is pretty much a bolt in and is very tuneable

Lowering the ride height will do alot for your 60 ft times as ed mentioned earlier.

TI

[awesomebill]

The air bag is o.k. and works fine but get running faster, or over 150 mph and watch what happens when you let off the gas. The right rear tire will be loaded way more and could lock up and could cause a mess. What goes fast must slow down faster if you don't have a chute.

try and stay the topic

This guys engine only puts out 600 HP and the car 60's in the 1.60's I dont see him going 150 mph any time soon.

If you read his comment, his car twist quite a bit. I think we are staying with the topic here. I know that the sway bar will virtually eliminate any twisting affect he has completely.
600 hp when properely used will put his car into the 10.20's at over 130. This is very fast and does require some suspension work. If I had 600 hp and the car was going 10.60's, I would be looking for a better 60 than 1.60. Meaning At 3500 lbs a 600 hp engine should put the car into the low 10's.
Any help with the car not twisting or using up the left rear tire and axle will excellerate the car faster threw the 60. And if he ever used NOS for just kicks, with what I have suggested would be no problem. Spend the money right the first time and the next time you won't have to.