Bogs only during off idle acceleration...
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From: Michigan
Bogs only during off idle acceleration...
My new setup is in the sig. The car runs great except for coming off of a stop sign. If I slowly put my foot into the gas, it runs okay. If I give it any kind of quick jab with the gas to get the car moving quickly, it bogs for a second or two (sometimes pops, I'm assuming a backfire in the intake) and then the car suddenly launches. After I get going, the car runs great. No problems under part or full throttle. It is only on the initial launch when this occurs. My idle/drive vacuum is about 6.5", and I just put in a 4.5" power valve. Is this a mismatch? Could my accelerator pump be bad/mismatched? Any help would be grealty appreciated. Thanks
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From: Michigan
Okay, I think I misworded my problem. It's more of a slight hesitation, not so much a bog. If the pumpers weren't working, wouldn't the car just fall on its face? The car runs awesome at full throttle. Thanks again.
Last edited by CamaroX84; May 4, 2003 at 11:19 AM.
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It sounds lean from your description. Your idle vacuum sounds incredibly low as well. Your cam duration is probably a part of that, but you should be generating more idle vacuum than that. What is the hot idle RPM, anyway?
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From: Michigan
The vacuum reading was in drive. In park, it's at about 10". I don't know what could be causing the low vacuum besides the cam. There is abslutely no vacuum leak. Hot idle RPM is about 700. Thanks again.
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From: Elizabeth, Colorado
Car: '94 Corvette
Engine: LT1
Transmission: 4L60E
Most of the time automatics with double pumpers require a little bit bigger Accelerator Pump Discharge Nozzle. In other words, you need to try bigger squirters...
http://store.summitracing.com/produc...earchtype=ecat
If your running a .028, try a .035 or something till you get rid of the off idle lean. Don't over do it though. If your nozzle are to big, you'll also pick up a bog. Dumping out black smoke will clue you in if there to big.
BTW: There is an accelerator pump tuning kit, which might save you some money in the long run. It comes with nozzles & cams.
Ron
http://store.summitracing.com/produc...earchtype=ecat
If your running a .028, try a .035 or something till you get rid of the off idle lean. Don't over do it though. If your nozzle are to big, you'll also pick up a bog. Dumping out black smoke will clue you in if there to big.
BTW: There is an accelerator pump tuning kit, which might save you some money in the long run. It comes with nozzles & cams.
Ron
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