MeanYellowZ

Is this a bad idea? Trying to get this figured out for a friend....running an F.I. pump designed for high pressure use, regulating it down to 5-7 psi for carb and running it all the time. Gonna hurt it? be okay?? I guess we're gonna use a nice 3 port return design. Any other problems you guys forsee with this combination?

Don't Know a Lot About F.I. Racing

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Currently own: 2001 Xtreme, 85 IROC, 87 S10
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greearhr

I ran such a set up with a Barry Grant V.F.I. throttle body injection system that ran about 15 psi. The pump was a standard 90 pounder.The V.F.I. didn't work out so I put the carb back on and dropped the pressure to 7psi. It worked OK but there was a lot of fuel running through the return line. It gurgled and may have aereated the fuel in the tank. Bottom line, it worked.

ede

randy why not go to a mechanical fuel pump? cost you about 20 dollars, if the cam has a drive lobe for a fuel pump, use the return line for a vent, or get a mechanical pump with a return.

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ICON Motorsports

1st & 3rd

Steves ZZ5

I agree with ede.

It's gonna be alot less expensive to simply run the mechanical pump that is already installed on PJ's engine. They do sell let-down regulators for FI to carb, but they're not cheap. Jeg's or Summit has them.

Now, simply plumb the pressure line from the tank, right into the inlet of the mechanical pump. You might as well leave the FI fuel filter right where it is under the car. Or, you can run a length of fuel hose in place of the FI filter and add a carbed type in-line fuel filter up front directly after your mechanical pump. I personally prefer the FI filter beneath the car, because it's less engine clutter in my opinion.

It's very important that you REMOVE the in-tank TPI pump, because it's of a gerotor design. You can't pull enough flow through this type of positive displacement pump if it's sitting idle in your fuel tank. Simply replace your in-tank TPI pump with a length of fuel line that reaches exactly to the point where the suction of the in-tank pump was (throw the pump "sock" away, since you won't be needing it). Make sure that you secure the end of that piece of fuel line so it doesn't decide to curl up in the future. If it does curl, you're gonna basically lose tank capacity since you are no longer picking up from the very bottom of the tank.

PJ. . . .Are you going to sell the rear end out of the GTA or what? I'm interested if you are.

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86 Trans Am WS6 Black with tinted windows, shaved door handles
ZZ4, Mini-ram, true duals
***Too many other mods to mention***

"In the future, cities will become deserts,
roads will become battlefields, and the hope of mankind
will appear as a stranger" The Road Warrior

Ray87Z

I've been running the Mallory 3-50 psi return style regulator on my stock TPI fuel pump for over a year now. No problems.

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray