Problem cutting a light
 

I have a 93 Formula f body firebird I run In D/PS.I am having trouble cutting a light with the car. I shallow stage, rpms at 1500 at start. I leave as the last yellow is starting to come on and the car gives me a .671 light. I made a second pass to make sure it wasn't me, it was another .6719. I have been fighting this all year. I have put air bags in the rear with 25psi in right rear, 5 in drivers. I have tried 35psi to 10 psi and no difference. Lower control arms are level with the frame ties. I have tried lowering them and it seems to hit tires harder. The torque arm is in the stock setting, but not mounted to the trans. Springs are v6 springs with a 1/2 coil cut off. The rear shocks are 50/50 new lakewood. Stock anti roll bar. I have 145#s of weight in the rear of the car to make weight. The converter is built for the car combination. I have 4.56 rear gears with 26x8.5 rear tires.
The front suspension has 6" of travel for the front tires to fall out of wheel well. Lakewood 90/10 shocks with stock springs on front with 1 coil cut off. I was thinking of making front end limiters so i could make the car move forward. In the car, it seems like the car is trying to rock back on the rear tires, while lifting the front. The 60ft times are great. Here are my times

1.608 60ft
8.10 1/8th
82.56 1/8th mph
12.82 1/4
102.89 1/4 mph

I run 22 psi in the rear tires. The 60s are very consistent, and the car runs dead on the money every pass. Ran two 8.102 Saturday in tt and dialed in a 8.09. Ran 8.10 1st rd and lost because i had a .6719 light. I practice on a practice tree every night. I am very consistent on it in several different situations.

I am going to lower the torque arm 1 1/4 inches in the front and see what happens. Is that the right move ? Also how many racers use front end limiters on there stockers? Is 6" to much travel? Was thinking of limiting to 4" and see what happens. I am looking to classracer for help. Thanks In advance.

Re: Problem cutting a light
 

It's a good sign if you're consistent. But is there another carb you could try? Could you have a carb "flat spot" that's not very obvious? Converter might be at least part of it, but that's still a lot to be "off".

Re: Problem cutting a light
 

It's a fuel injected car. It could possibly be converter. I ordered this one from mark yacovone . I have never tried another converter in it.

Re: Problem cutting a light
 

Whats the launch rpm?

Re: Problem cutting a light
 

Starting line rpms are 1500. I've tried 2000, but 60s slowed down and didn't seem to improve lights.

Re: Problem cutting a light
 

I'm not familiar with FI cars, but I suppose it could still have a "flat spot" at the hit if the fuel curve isn't correct. Kind of like having an accelerator pump squirter that is way off on size and/or duration.

Off hand, I can't imagine a converter affecting RT's that much.

As an experiment, perhaps you can compare yourself to someone else in another car or practice tree to see how much of a variable you might be. Just trying to cover all the bases.

Re: Problem cutting a light
 

Joe, How high can you foot brake it to? I can't imagine a higher starting line RPM not affecting r/t.
Being a Pure Stocker with limited duration, it may indeed go faster leaving at a low RPM.
You might end up with an eliminator setting and a different one for qualifying ..Not unheard of.

Re: Problem cutting a light
 

The last thing to leave the line is the front wheels...start limiting all the wasted motion that the car goes through........too much front end travel......not enough air in slicks ect....even consider solid body bushings...

Re: Problem cutting a light
 

How much air in the front? With 26" it would take a large change in air pressure to affect rollout. Also, how high can you make the rear tires? Lastly, you sound consistant at the tree. Try (in testing of course), bumping in deeper on the line. Two runs only bumping once, then two runs bumping twice etc. It is worth a shot.

Re: Problem cutting a light
 

You might want to try a taller rear tire. I believe the class allows a 29.5" x 9".