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Is the stock hard fuel line fine for MPI?

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#1 Preludedude


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Posted 15 April 2018 - 07:55 PM

Is the stock fuel line sufficient for running a MPI setup?  I have a Walbro 255 pump but wasn't sure about having to upgrade the lines

I plan on getting an Aeromotive adjustable FPR with this setup....

#2 polarisman14



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Posted 15 April 2018 - 08:47 PM

I ran a sard adjustable fpr, Russell in line filter, walbro 255 pump on mine with 75# injectors. Ran 22psi boost on a med-large turbo on wiseco pistons upward of 400whp on stock hard lines with no problem.

'89 Starion SHP...FIP MPI, 3" Exhaust, TEP Cam, Turbonetics 11021-BB T3/T4 Turbo, Treadstone Manifold, 75# injectors, Mookeeh Sway Bars, GC Coilovers, Saleen Replica Wheels, the list goes on...AND IT FINALLY RUNS!!!


#3 scott87star


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Posted 16 April 2018 - 08:59 AM


Fuel Line Sizing — What Size Do I Need?

by Admin on November 16, 2012 in General, Technical Articles

Lots of strange information out on the internet regarding fuel line sizing and it seems like most of the time people run way more diameter fuel line than they need. This is an interesting article that I came across that seems to be pretty relevant.
Quick reference for AN to Inch line conversion:
-6AN = 3/8″
-8AN = 1/2″
-10AN = 5/8″
-12AN = 3/4″
Fuel Line Sizing
A question that is often asked of me when dealing with high horsepower applications is: “My fuel line is nominal 3/8” id. Don’t I need to increase the size of the fuel line to at least ½” id (from a #6 to a #8 or #10) to support say 600 HP”?
The answer is “NO”! A 3/8”id fuel line can easily support 600 HP given sufficient “pump head”! Given a big enough pump a 3/8” steel line could support 1000 HP.
The simple way to know is to install an electronic fuel pressure gage. If the pressure falls as the engine RPM’s go up you need more pump head. More pump head can be achieved with a bigger pump, higher pump voltage and/or increasing the line size. But before you do check out the following (and remember a dirty fuel filter is often the culprit of falling fuel pressures!).

If you're trying for big HP and not logging fuel pressure, well, that's a waste of your time.
Now selling true plug and play megasquirt!  Absolutely the best value in stand alone ECU's out there.

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ECU Vendor link:  http://www.starquest...howtopic=137426

#4 Fuze


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Posted 16 April 2018 - 10:07 AM

Dude it's fine as far as size goes...

Insta = @battlemagnet

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#5 croquest87


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Posted 13 May 2018 - 06:59 AM

Only thing l did is eliminate the cone pre pump filter and using metal wix before pump  w no damper after the pump to stock lines. In engine bay l am using 6an straight to stock filter and 6an to fuel rail w no banjos. And 6AN from fuel rail to rising fpr and 6AN from FPR return to stock return line it works fine. I did make small adapter bracket to bring stock filter holder up higher about 1.5" for more room for straight 6AN adapter and line for the bottom connection. Works well.

Edited by croquest87, 13 May 2018 - 07:00 AM.

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