getting a noticeable bog under rapid acceleration, any ideas

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
hey grumpy I installed a 750 cfm holley carb ,
on my chevelles 383 and I'm getting a noticeable bog under rapid acceleration,, I have yet to start tuning, but I have verified the fuel pressures a rather consistent 5.5 psi, and the floats are correctly set so fuel levels keep the sight plug lower threads barely damp at idle, I have to ask if the primary acceleration pump squirters , should continue to provide fuel as the secondary acceleration pump squirters kick in,or do they trade off, , for example does the primary acceleration pump supply fuel until the secondary's are fully open, even though the secondary acceleration pump has kicked in at some point, any ideas

low pressure electrical fuel pumps are available for carb applications
http://garage.grumpysperformance.co...hing-the-drive-train-to-the-engine-combo.741/

http://garage.grumpysperformance.co...electing-a-torque-converter-stall-speed.1715/

http://garage.grumpysperformance.co...late-gear-ratios-and-when-to-shift-calcs.555/

all it takes is a tiny bit of research and some math to calculate the ideal rear differential gearing, tires size etc. and transmission gear ratios, and you can certainly select the correct torque converter stall speed if you have a dyno graph of your engines power curve without much difficulty, an hour or so spent in reading and research will provide you with a great deal better performance from most cars.
and a couple days worth of research and doing some math on all of the power trains component parts will provide you with a wealth of info that can prevent you from making costly mistakes.



https://www.holley.com/products/fue...ed_fuel_pumps/carbureted_electric_fuel_pumps/

http://www.jegs.com/c/Fuel-Carbs-Intakes_Electric-Fuel-Pumps/10307/10002/-1

http://www.edelbrock.com/automotive/mc/fuel-pumps/

http://www.mechanicalcaveman.com/best-electric-pump-for-carburetor-fuel-pump-review/


the primary squirters fuel volume should over lap a great deal.
it certainly should not run short of fuel early, and should still be concurrent with the secondary squirters, ie over lap, and both primary and secondary jetting and power valves should be selected to keep the fuel/air ratios reasonably consistent during the transition phase.
yeah I know most of you skip reading the links, but for those that want answers,
the links and sub-links will provide a great basic reference


http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

http://garage.grumpysperformance.com/index.php?threads/holley-accelerator-pumps-cams.1790/

http://garage.grumpysperformance.com/index.php?threads/holley-annular-vs-down-leg-boosters.5229/

http://garage.grumpysperformance.com/index.php?threads/holley-carb-power-valves.1639/

http://garage.grumpysperformance.com/index.php?threads/spark-plug-info.202/

http://garage.grumpysperformance.com/index.php?threads/verifying-your-real-advance-curve.4683/

http://garage.grumpysperformance.com/index.php?threads/the-trucks-just-not-running-well.13435/

http://garage.grumpysperformance.com/index.php?threads/reading-plugs.5428/
 
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