Author Topic: Qjet guys with more than 500 hp?  (Read 1718 times)

Offline 77cruiser

  • Qjet Hero
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Qjet guys with more than 500 hp?
« on: October 11, 2016, 02:23:00 PM »
What does your fuel system consist of? Are you using a mechanical pump or electric?
Currently I'm using a carter 120 street pump & just added a 1/2 inch line from tank to pump & it still leans out a bit at around 5700 - 6000.
Cliff said he had issues with the same pump not keeping up too.
I went to the track once this year & ran 12.15 @ 112 it layed down @ the top of 1st & 2nd.
Maybe the best option is to go to some kind of electric pump, but I'm trying to avoid that.
Jim

Offline qjetsrule

  • Carb lover
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Re: Qjet guys with more than 500 hp?
« Reply #1 on: October 11, 2016, 10:46:06 PM »
I ran a '70 olds 442, 11.80's @ 113 with points, stock $18 autozone mechanical pump, and stock fuel lines. I think a quality fuel pressure gauge is important to monitor pressure throughout the rpm range. this helps troubleshooting performance problems like hesitation, and power fall off at high rpm. holley's fuel pump calculation figure about 41gph for a 500hp motor which is well below most aftermarket pump's output. their engineers also say pressure and volume are inverse proportional, meaning as pressure increases volume decreases and vise-versa. good luck

http://documents.holley.com/techlibrary_fuel_pump_tech_info.pdf