Fuel Pump

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05-21-2005, 02:13 AM

philkeoghan

Junior Member

Thread Starter

Join Date: Mar 2004

Posts: 16

What are the signs that your fuel pump isn't pumping enough for your modifications? high knock readings? strange engine noises, not performing properly under boost?

how do you tell if it's keeping up with your demands? I have a datalogit but I am suspect that the fuel pump doesn't keep up

05-21-2005, 05:50 AM

jspecracer7

Senior Member

Join Date: May 2002

Location: Okinawa, Japan

Posts: 4,928

Your fuel pressure drops off at high rpms is the best indication you need to upgrade.

05-23-2005, 04:08 PM

rxstephen

Junior Member

Join Date: May 2005

Posts: 4

[quote name='jspecracer7' date='May 21 2005, 11:50 PM']Your fuel pressure drops off at high rpms is the best indication you need to upgrade.

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Correct. I tested my fuel pressure and found that it would drop below regulated (40psi plus the boost level you are running) when I went much over 4500 rpm on WOT.

Since then I have re-wired my pump using a separate relay and heavy duty wire to the battery and my stock FD pump will now maintain correcft fuel pressure right up to the red line and 98% duty cycle on the stock injectors. I also found that I had to lean out the conservative PowerFC base maps by quite a lot.

05-23-2005, 04:33 PM

jspecracer7

Senior Member

Join Date: May 2002

Location: Okinawa, Japan

Posts: 4,928

That is a very common problem with the FD...the 9v (or is it 6v) to 12v switch during WOT. This is the reason why I always run a separate wire/relay to the pump. What mods are you running?

05-23-2005, 05:08 PM

rxstephen

Junior Member

Join Date: May 2005

Posts: 4

[quote name='jspecracer7' date='May 24 2005, 10:33 AM']That is a very common problem with the FD...the 9v (or is it 6v) to 12v switch during WOT. This is the reason why I always run a separate wire/relay to the pump. What mods are you running?

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The engine has stock porting, injectors and turbos, it has:

FMIC (home made 3" plumbing with 450x300x76mm core)

Trust DP

mid pipe with resonator

RacingBeat catback

Race spec radiator

PiNZ water injection

PowerFC with Datalogit (plus WB O2)

Boost set at about 14psi on the track, 17psi on the street (water injection is a wonderful thing)

I'm having huge problems at the moment with fuel starvation on the race track with anything less than 1/2 a tank in left hand corners. I put in some fuel cell foam last night that fills up about 90% of the tank and the problem if anything is worse, but I've only been testing with 20L in the tank.

I'm looking at fuel surge tank options now.