So...the big question....
What size fuel pump do I need for my combination?
This is one of those cases that "Size Does Matter"
Let's look at some of the variables that need to be considered before you make that final decision.
G-Forces, these pumps as most fuel pumps designed for carbureted engines are designed to push fuel at relatively low pressures which are created by resistance or restriction in the fuel delivery system. When you launch and generate anywhere between 1.5 and 3 G's all the fuel in the column or fuel line is being driven back to the pump at the G force times the weight of fuel in the line. Without a pump that can overcome these forces the carburetor will temporarily run low on fuel. Will it melt down the motor, not in anything but an extreme condition, will it hurt performance, yes definitely. If you want the best possible and most consistent time slips then the pump must be able to handle the task at hand.
BSFC, so you did the calculations, weight to gallons conversion and your engine mathematically requires only 80 GPH. True, but did you account for the G force's of the fuel trying to reverse itself on launch, what about the gear ratio of 2.45:1, remember the HP formula- weight/over distance/over time?
If your fuel pump isn't up to the task it's very difficult to diagnose unless the problem is extreme and the engine stalls 20 feet off the line. Doing a plug check from a 60 foot shut down or 1st gear is pretty tough and by the time you get to the stripe the pump has recovered and the plugs look fine.
"I run a 10 second, 3500# car, Holley Blue pump and 5/16 line and it works great" and as soon as we put on the correct fuel pump and lines the car cuts .2 to .5 off the ET, runs way more consistent, drops 100 degrees or more on the EGT and 10 degrees cooler at the stripe.
If your not sure what pump you need, call that's what we do everyday, build, design and install fuel systems.
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