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Low fuel pressure at high RPM

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Old 08-16-06, 05:59 AM
  #1  
240RWHP 270TRQ @ 0.9Bar

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Low fuel pressure at high RPM

Steve Kahn was here on the weekend to tune my car. We managed to get more done this time than before until we ran into another problem. It seems that my fuel pressure is dropping at high RPM. We were doing 3rd gear pulls at about 10psi and at about 6000RPM the fuel pressure would drop sharply and I would lean out.

Steve upped the duty cycle on the injectors to compensate, but I'll have to fix this before he comes back again, possible in Sept.

Steve recommended changing my fuel filter to start, but I'm also suspecting my FPR, just because I don't know what kind it is, if its working properly or if is even installed properly.

I have 550cc primarys and 1600cc secondaries, as well as a 255lph Walbro fuel pump. The engine is street ported and I'm running a TD07-25G turbo setup w/ all the goodies. The car is a S5 FC3S.

Any ideas would be appreciated.

-Kenji
Old 08-17-06, 07:58 PM
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doesnt sound like the fpr or the filter. i think its the pump
Old 08-18-06, 05:40 AM
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Run another walbro .
Old 08-18-06, 07:43 AM
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spending too much money..

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yeah thats a big *** turbo for such a little pump but of course at 10 psi you couldn't be seeing all that much power as 10 really isn't alot for that turbo.
Old 08-20-06, 08:36 AM
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have you considered getting larger fuel lines ...i had a similar problem and this worked a treat!
Old 08-20-06, 12:05 PM
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240RWHP 270TRQ @ 0.9Bar

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Someone else mentioned the bigger fuel lines. How big are we talking? Will it really make a difference??

Keep it comming guys.

-Kenji
Old 08-20-06, 02:52 PM
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bigger fuel lines make all the difference in the world.

10an feed
8an return
Old 08-20-06, 05:11 PM
  #8  
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12 an feed and 6 an return..... thats my set up....

dont know if it will work though


lol
Old 08-20-06, 10:01 PM
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that would be best, give you sme growing room in the future, but in all honesty id get away from that in tank bullshit.

high hp = sump + aeromotive or weldon fuel pump
Old 08-20-06, 10:43 PM
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On an FD, you can make 500 rwhp with stock fuel lines and an in-tank pump (apexi bnr). Is the FC that different?
Old 08-20-06, 10:59 PM
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spending too much money..

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nope same numbers for the fc as well. Wtf! 10 AN fuel lines that is freakin' crazy!
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