MichaelB145

I am dropping fuel pressure at WOT above 17lbs of boost. I currently have the RX7.com fuel pump (which Ari said its good to 500hp), Aeromotive FPR, and 1600cc secondaries. I am using stock fuel lines and stock primaries. What should I do? Could I do this.....


I have a brand new fuel pump from the RX7store.net extreme fuel system that I did not use. Could I use this fuel pump for my primaries, and use the RX7.com pump for my secondaries by using the carbon return line (cleaned out)? Its not being used anyways now. That way I could avoid runing bigger fuel lines and saves a bunch of money. Does anybody see anything wrong with this? I saw a FD at NHRA running 10's that used this set up. I probably would upgrade my primaries to 850's unless it would not offer any help.

My setup on 93 FD3S R1
Atkins 13B 3mm, Cryo frozen, Water jacket mod, Clearance rotors
A-spec GT35/40
Power FC w/ datalogit
Greddy 2 row FMIC
Fluidyne radiator

BDC tuned to 17lbs...but would like to go to 25-28lbs if tuning allows

MichaelB145

By the way...I have a 55 gallon drum of 108 VP CSP in the garage....the car does not see pump gas and I live at 5280ft above sea level.

cewrx7r1

iTrader: (2)

Two pumps would require two FPRs to be optimum.


Go search for my post on rewiring the FP for more voltage (power).

Carl Byck

Only if you use seperate returns, which you would not ordinarily do. Basicly, bad idea IMHO. Two pumps is fine, a single FPR will allow you to get the fuel pressure right. Why the two pumps though? What are your HP goals? Is the big pump not enough? If you really want to do it right, the smallpump would feed a surge tank, and the big pump would send the fuel up front. Carl

MichaelB145

Looking for 550 hp....currently Im tuned at 17 lbs at only 431hp. I would have never guessed I would need a second FPR. The set up in which you remove the stock emissions fume line sounds like is pretty popular....but your the first to mention the dual FPR.

TT_Rex_7

A single external fuel pump would handle those sort of power levels without a problem. However, noise becomes an issue. Most external fuel pumps can be mounted inside the tank though. This will help with noise levels.

If your set on running 2 fuel pumps, use 2 of the same kind. I think cewrx7r1 mentioned 2 FPR's because each pump will flow a diffrent amount of fuel at the same voltage. Therefore, it'd probably require 2 FPR's to set the correct fuel pressure. A single FPR, with dual inlets/single outlet may not be able to control the fuel pressure since 2 diffrent flow rates are entering it.

-Alex

MARTIN

No, you need 2 fprs if you want 2 seperate returns like micheal wants to run.. He wants to run a pump to each rail.. Which is not a smart way of doing things.. 2 internal pumps will be enough for that, and you can control the flow with a single adj. fpr.

MichaelB145

Is the FPR supposed to be installed before or after the fuel rail? Just wondering if that may be my problem. Has anyone put down about 500 hp w/ RX7.com fuel pump, stock lines, Aeromotive FPR, w/ 1600cc injectors? Im maxing out at 17lbs at 431 hp. I have had others tell me that set up is possible to about 23 - 25 lbs making close to 550hp.

TT_Rex_7

Which they make dual inlet FPR's for. You don't have to run 2 return lines.

However, I missed the part in his post about running a diffrent return for the second fuel pump!

-Alex

PDViper77

iTrader: (9)

Hey, I have 2 nippondenso FPs feeding each of my 2 fuel rails (pri 1000cc, sec 1600cc). My FPR has 2 inlets and one return so the two fuel rails go to each side of the FPR then the return line comes out the bottom. My fuel lines are made up of 3 3/8th" or -6 SS fuel lines (2 feed, 1 return). I have steady fuel pressure with this setup so that is not a problem. I did this to support my GT42R, but I need a new clutch before I can crank up the boost.

Rhymin

You sure do like talking about your 55 gallon drum?

z8cw

What was your idle fuel pressure and fuel pressure at 17lbs of boost? The regulator needs to be after the fuel line otherwise you wouldn't regulate the pressure.