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throttle hesitation
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http://www.clubcobra.com/forums/backdraft-racing/86864-throttle-hesitation.html)
| Cashburn |
04-14-2008 10:52 AM |
Hello,
You can change the primary jets to eliminate the stumble. In our area/elevation we up the jets a couple of sizes. Typically the carbs show up with 68's on the primary. We usually jump to 71's sometimes 72's to get rid of the stumble. You can also increase the squirter, but this sometimes will lessen it but not eliminate it. Check to see if you have a 50cc accel pump or 30cc. The lightness of the car makes it a bit more difficult to dial in. Don't get rid of the vaccuum secondaries IMHO. The mechanical is better for a race car, but on the street a properly dialed in vaccuum secondary responds better. Check on the jets and see what you got.....
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| Got the Bug |
04-14-2008 11:18 AM |
Warren - Thanks for the tip on the Holley book. I got to get myself edumicated.
Jay - Any tips regarding low RPM surging? I no longer have the stumble, but noticed a low RPM surge over the weekend.
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| wtm442 |
04-14-2008 11:53 AM |
Quote:
Originally Posted by Got the Bug
(Post 834593)
Warren - Thanks for the tip on the Holley book. I got to get myself edumicated.
Jay - Any tips regarding low RPM surging? I no longer have the stumble, but noticed a low RPM surge over the weekend.
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Check to make sure the float levels are not too high. Also could have plug going south or a bad plug wire. If its at a really low RPM, increase the idle speed :LOL::LOL::LOL: If you hear any noises, turn up the radio :JEKYLHYDE:p:LOL::eek: |
| MaSnaka |
04-14-2008 12:15 PM |
It seemed the first and only thing Holley Tech said to me was to get a bigger accelerator pump nozzle. Didn't really seem to care about anything I had to question him on. I communicated via the email and it took weeks to get a reply from Holley. My second request for further info was completely ignored, again via the email.
The bigger nozzle helped. I think I still need a bigger one.
It's my understanding that the jets sizing has nothing to do with the hesitation. When you open the throttle most all vacuum is lost and thats the purpose for the accel. pump. It only works for the first squirt of fuel to get the rpms up. Once vacuum is restored fuel is pulled through the jets at the rate the orofice allows, hence your A/F mixture.
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| Cashburn |
04-14-2008 12:19 PM |
Check your float level.... throw a vacuum gauge on, could be a slight vacuum leak at the manifold or throttle shafts..... any oil consumption?
May just need to richen up the idle circuit.....
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