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Author Topic: Do I need a better pump.  (Read 2947 times)

Offline 77cruiser

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Do I need a better pump.
« on: July 27, 2016, 01:02:09 PM »
I have this one.

https://www.summitracing.com/parts/crt-m6900/overview/make/chevrolet

But I have 5.5 psi at idle but drops to 3 psi at WOT. That checking at the pump not the carb so it could lower at the carb.
Stock 3/8 line from tank, 1/2 inch pickup in tank no sock to plug.
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Jim

Offline qjetsrule

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Re: Do I need a better pump.
« Reply #1 on: July 27, 2016, 04:20:33 PM »
according to holley's calculator, that pump will supply a 1000hp engine. unless you got a bad pump, something else may be wrong. good luck

http://documents.holley.com/techlibrary_fuel_pump_tech_info.pdf
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Offline Cliff Ruggles

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Re: Do I need a better pump.
« Reply #2 on: July 27, 2016, 07:18:42 PM »
I tried one of those pumps decades ago and found it to be little if any better than a stock pump.

It would NOT keep up with the 428 engine only making about 400hp that was in my car at that time.  I was trying to feed it with stock lines and modified pick-up as well.  Not sure if it needs bigger lines, or what was going on but I removed the pump and went to an electric pump and things were fine.......Cliff
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Offline 77cruiser

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Re: Do I need a better pump.
« Reply #3 on: July 28, 2016, 04:28:14 AM »
I know the pump should supply more than what I have. I thinking restriction before the pump.
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Jim

Offline Jeffs68

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Re: Do I need a better pump.
« Reply #4 on: July 28, 2016, 07:18:06 AM »
Are you having a drivability issue, is the carb running out of gas, or are you just worried about the pressure drop?
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-Jeff

Offline 77cruiser

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Re: Do I need a better pump.
« Reply #5 on: July 28, 2016, 03:53:43 PM »
I goes lean in 3rd gear.
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Jim

Offline Jeffs68

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Re: Do I need a better pump.
« Reply #6 on: July 28, 2016, 04:58:52 PM »
Are you using a A/F gauge?

Is it losing power?
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-Jeff

Offline 77cruiser

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Re: Do I need a better pump.
« Reply #7 on: July 28, 2016, 07:27:30 PM »
Yes to both.
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Jim

Offline Jeffs68

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Re: Do I need a better pump.
« Reply #8 on: July 29, 2016, 06:25:51 AM »
So what is that 77 cruiser, what motor is in it, what's the carb # (maybe Cliff can make a recommendation) , what rear end and transmission?
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-Jeff

Offline 77cruiser

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Re: Do I need a better pump.
« Reply #9 on: July 29, 2016, 07:59:22 AM »
421 sbc dyned 530 hp, 200-4r 3.73 rear. 4200 lbs. of Monte.
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Jim

Offline Jeffs68

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Re: Do I need a better pump.
« Reply #10 on: July 29, 2016, 08:20:34 AM »
I would try an electric pump.
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-Jeff

Offline 77cruiser

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Re: Do I need a better pump.
« Reply #11 on: July 29, 2016, 07:35:53 PM »
I wish you would have said that.
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Jim
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