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09-21-2014, 08:19 PM | #1 |
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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. Last edited by russellauto1; 09-21-2014 at 08:32 PM. |
09-21-2014, 10:16 PM | #2 |
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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".
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LOCOMOTION Racing |
09-21-2014, 10:18 PM | #3 |
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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.
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09-21-2014, 10:21 PM | #4 |
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Re: Problem cutting a light
Whats the launch rpm?
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James Boyce 6052 K/SA Stock National record holder 2015,2018,2 times in 2022,2023 |
09-21-2014, 10:27 PM | #5 |
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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.
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09-21-2014, 11:06 PM | #6 | |
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Re: Problem cutting a light
Quote:
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.
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LOCOMOTION Racing Last edited by Myron Piatek; 09-21-2014 at 11:09 PM. |
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09-21-2014, 11:39 PM | #7 |
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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.
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09-22-2014, 12:11 AM | #8 |
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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...
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09-22-2014, 08:02 AM | #9 |
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Re: Problem cutting a light
All these ideas are great.
Mark, the harder I leave on the starting line, the harder the car lifts the front and hits the rear tire. When the front of the car lifts more, the slower the car reacts. The converter works great. I cannot see it being that because of how consistent it is. Gump, I have thought about taller tires for the rear. I have non to try at the moment. I have 50psi in the front tires trying to make them the least amount of contact with the ground. They are 165/70/r15 volkswagon tires. Not race front runners. I have tried bumping in 2 bumps at the line. It kills the et and made the lights drop to .590- .600 range. As far as the efi having a flat spot. I have tried another chip in the ecm from another tuner and it slowed the car down and the reaction got slower. I Have cut some .530 lights with the car, but I was anticipating the light. All these Ideas are great. What about torque arm angle? Do I have too much front end travel? Thanks AAron |
09-22-2014, 08:25 PM | #10 |
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Re: Problem cutting a light
Cheap way out: Leave at a different spot on the tree?
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