A couple ?'s on suspension setup

Doug Jacobson

Altitude Compensated
May 24, 2001
I don't like throwing the back end of my car sideways off of the line. I've been able to get a 1.86 60' spinning all the way out and would like a little help.

I have no swaybar, 2 airbags, boxed lower controll arms with poly bushings, 26x11.5x15 ET Sreets on 9" rims, and regular Koni shocks. I've been running 15 psi in the slicks and 15 psi in the right air bag and 7 in the left. I leave at 12 psi and think with a better 60' I could break the 11 second barrier on this tune. I cut a 1.74 60' last year with all stock stuff with the same tires and would like a little help with setup to get the car off the line better.

What tire pressure and airbag pressure would net some better times?
I hope you mean no Front swaybar when you say "no sway bar". The rear bar helps a lot during the launch.

For Air bag pressures, I recommend 20 psi on the right side and minimum on the left to start. The idea of the differential pressures is to equallize rear tire "weights" at launch boost. By powerbraking with one rear tire on the track scale, I found that more than 20 psi was required on the right side for the weights to be equal (I have no driver side airbag).

The more air you put in the driver bag, the more you have to put in the passenger to compensate.
Yeah the rear swaybar is still there. I'm definataly going to up the pressure in the right bag next time out. Does the tire pressure seem OK or am I right in assumeing that every car needs different tire pressure and a testing will only tell me what is right for my car?
Ditch the airbags and get a Wolfe swaybar.

Save yourself a lot of headache with those damn things, and you can change pre-load on the rear in a few seconds. Voila! No more torque roll. When you pick tires up off the ground in front, it will do so nearly even since it helps keep the torque evenly distributed to *both* rear tires...
Suspension setup

You don't say to which side the car is going to. This will give an idea of what the problem are related to the bag psi.
Also, are these 12psi launches w/ a park brake or ???
Have you tried to switch the shocks, tires or springs side for side and see what happens??
Are the tires the same rolling diameter?
Is the rear axle strait in the chassis?
Has the car been wrecked?
What is the pinion angle?
What shape are the rear bushings in? Upper and lower.
Is the steering wheel centered so you are not leaving w/ the ft wheels cocked?

These are some ideas to check as a process of elimination.

Back under the car:D
Hey Doug!
Congrats on the new ET. I meant to say that and get caught up on how it went Friday when I saw ya Saturday but things kinda got busy. Do you have any good videos of the car launching? If so I may be able to help you figure some things out.. Give me a call if you'd like.

Sounds like Friday was the day to be racing!

Chuck, I'll try to give answers by the Numbers

1. Car goes to the right then straightens out.
2. Tranny Brake - Stage Rite
3. Haven't tried that yet.
4. Yes
4. I would assume so. But you know what happens when you assume. :D
5. No
6. Stock, I have a pinion snubber but it hasn't touched anything since I put in the airbags.
7. The uppers are stock and in good condition. The lowers are Poly and almost new.
8. I think so, I try to aim it down the track. :) Straight out of the burnout box to the line.

Kevin, No videos I need it to launch like the purple truck. I think I could cut a 1.3X 60' :eek: Oh yeah the 8.90's would be nice also. :) I took the radiotor to be cleaned today with the idea of going back Friday. But the weather said it's going to be in the 90's friday so I may wait.

Thanks, Doug
you sure your posi is good??? you should be able to hook with your setup easily, even on a crappy track...are you spinning the tires on the rim?
Try launching with less boost. You may not be spining the tires off the line, but you might be slipping 30 ft out. If you launch at a lower boost level it will be further down the track before you make full power. Just a thought. Works for my car, but if you launch with too little it will also hurt. The track was really bad Friday night after the sun went down. Oh yeah, my ET streets like really big burnouts.
Azgn, I might be spinning the tires on the rim. On my first run I forgot to lower the pressure (20psi) and I noticed little rubber strands around the right rim when I dropped the pressure. I didn't notice it any later in the eve. after I dropped down to 15 psi though. I don't run any tubes but have the tires glued to the rims with 3M weatherstrip adhesive though. I may switch tires side to side to see if it may make a difference.

Brian, If I leave at any lower boost my 60' times drop into the 2.0 zone due to a severe lag problem with my convertor that I'm trying to sort out. I wish I could get the times you were getting on regular radials though. :)

BTW Brian, Did you go home with any money? Chad and I were talking about that and we both were kicking ourselves for not entering in the EFI class witha a little De-Tune. was the 11.92 your best run ever on the street radials? You really got the holeshot on that run.
I won $75 for the 3rd place finish. That will pay for part of the gas to get there. Yes, the 11.92 was my best pass ever on radials. When I figured out how to launch it the track hooked up great. I need to leave the chip timing alone and practice driving some more. That was the only pass all day that I didn't spin the tires somewhere on the track. I had a really bad reaction time on that run, but his was worse. I could hear him trying to catch up all the way down the track. I went a 11.92 @ 114, he went 11.93 @ 120. That was some good fun.

i run 28x10.5 mickeys on 10inch rim stock control arms mosier heat treated axels stock pos 30lbs air rt side 12 or 14 left and about 10.5 lbs air in slicks car 60s low 1.5s leave line with at least 12 lbs sometimes 20 psi boost hang on its a ride try this and see what happens good luck bret rudbeck ps might be those tires