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Old 04-14-2006, 06:31 AM
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Humbucker Humbucker is offline
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Join Date: Dec 2004
Location: Chattanooga, TN, TN
Cobra Make, Engine: Superformance #1408
Posts: 80
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Default More carb tuning problems.

Well, I'm just about at the end of my upgrade project. Now that all is done, I just have some minor tuning issues. The car is running like a scalded dog, but I do have one little issue.

It seems to happen at lower RPM, perhaps 1800-2500. The throttle response curve doesn't seem as linear as it used to. The problem seems to be more prominent in 1st, 2nd, and 3rd gears. I can apply the throttle and feather it the best I can and it seems to accelerate somewhat and then, *bam*, the flood gates open. This causes me to break the tires loose in 1st about 5% of the time. The best I can figure would be a transition problem. The following excerpt from http://www.nastyz28.com/perftune.html seems to apply.

"Transition

The system controlled by the main jets does not want
to come in early. The idle system is at the end of its
delivery and the main jets do not want to feed because
they're not getting enough signal. There are many ways
to fix the problem. Less high-speed air bleed will help.
You can go a little richer on the mains. Any air bleeds
above the fuel level will slow down the initiation of
the main jets. This goes for the small air bleed in the
dogleg of the high-speed air channel in the metering block.
The drawback of small high-speed airbleeds is that the
system goes rich under full power. Now you have the
information to go play."

Does this sound like it could be my problem? Also, before the new heads and intake, I was running 71's in the front & rear. I rejetted to 76 in the primary (thinking I was initially at 72's). Could this be the problem as well? I was thinking of backing down to 73's in the primaries and trying again. Opinions?

Thanks all! I'm just about to the point where I can start giving advise now. It's been a great learning experience.
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Jake - Ringgold, GA
Superformance #1408
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