Question about testing fuel pressure
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Question about testing fuel pressure
Hi guys. I have a 1985 Corvette with a lot of mods, and I suspect that my fuel pump may be insufficient at this time. My buddy has a dyno that can only go up to 300 rwhp. My fuel pressure gauge doesn't extend long enough where I can tape it to the windshield. If I put the car on the dyno and run it with the gauge hooked up, will it simulate me driving on the road for this test? I want to see if fuel pressure drops at Wide Open Throttle at high RPMs.
Thanks!
Thanks!
Drifting
Joined: Feb 2013
Posts: 1,465
Likes: 12
IF you have access to a dyno and can get the car safely strapped down and make a pull, someone could watch the gauge and you are making said pull and watch for fuel pressure drop.
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
Not much to go on here, but with lots of mods, a longer hose or longer-hosed FPG is a small expenditure with a potentially huge payoff.
The injectors need to be sized for the power produced. and the ECM needs proper programming, which is a project for it to run mods.
The injectors need to be sized for the power produced. and the ECM needs proper programming, which is a project for it to run mods.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
There is no reason why a stock fuel pump can't support 400HP. What is critical is that the fuel filter is new, the lines have no kinks or have been damaged and the fuel pump "sock" is clean. OEM fuel pumps have a "pulsator" that can be removed and a short piece of rubber gas line can be installed. The interior diameter of the OEM fuel lines are large enough to support the necessary volume of fuel for 400HP.
Does your car have an adjustable fuel pressure regulator? If not, get one and set it so it provides the stock pressure. Then fuel pressure can be adjusted as necessary.
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Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Then it's not a "dyno" in the sense that it measures power output of an engine. Given the mods you had listed, that "dyno" is not going to support WOT pulls with your car on it. And that is what lots of people are waiting to see from you; the results of some dyno pulls. You need that to determine what power the engine is making so that you can determine what to do next.
There is no reason why a stock fuel pump can't support 400HP. What is critical is that the fuel filter is new, the lines have no kinks or have been damaged and the fuel pump "sock" is clean. OEM fuel pumps have a "pulsator" that can be removed and a short piece of rubber gas line can be installed. The interior diameter of the OEM fuel lines are large enough to support the necessary volume of fuel for 400HP.
Does your car have an adjustable fuel pressure regulator? If not, get one and set it so it provides the stock pressure. Then fuel pressure can be adjusted as necessary.
There is no reason why a stock fuel pump can't support 400HP. What is critical is that the fuel filter is new, the lines have no kinks or have been damaged and the fuel pump "sock" is clean. OEM fuel pumps have a "pulsator" that can be removed and a short piece of rubber gas line can be installed. The interior diameter of the OEM fuel lines are large enough to support the necessary volume of fuel for 400HP.
Does your car have an adjustable fuel pressure regulator? If not, get one and set it so it provides the stock pressure. Then fuel pressure can be adjusted as necessary.
I also have an adjustable fuel pressure regulator and am running 60 PSI, but my engine gets progressively leaner the higher the RPMs go. And my tuner was having problems getting that to come down at high RPMs which is what makes me suspect the possibility of an insufficient fuel pump.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
So go to your nearest auto parts store and buy a 3 ft piece of high pressure fuel line, two steel or brass connects to splice the two hoses together and a four screw hose clamps and cut that hose to your gauge in half and splice in the 3 ft hose. Problem solved. 
Tape the gauge to the windshield and run it.
Tape the gauge to the windshield and run it.
Melting Slicks
Joined: Apr 2007
Posts: 2,616
Likes: 111
12 inches is looking for a buddy.......
http://forums.corvetteforum.com/c4-g...-my-buddy.html
Good luck!
http://forums.corvetteforum.com/c4-g...-my-buddy.html
Good luck!
Last edited by 856SPEED; Jul 20, 2014 at 05:31 PM.
Melting Slicks
Joined: Feb 2014
Posts: 2,409
Likes: 44
From: NC
12 inches is looking for a buddy.......
http://forums.corvetteforum.com/c4-g...-my-buddy.html
Good luck!
http://forums.corvetteforum.com/c4-g...-my-buddy.html
Good luck!
