As long as you have good enough wiring the Walbro 450 would be fine.....in E85 i don't think there are many other options from walbro......and i wouldn't trust anything else as an in-tank main pump, it does sound like you have a lazy pump....

China FPR's...

Nick73, 350Kpa is 50 psi, about right(higher than stock 300Kpa) for a base pressure for 1000cc injectors to aid atomisation.

You could bench test your fuel system somewhat, use an airline on the FPR and pump 2 bar into it with a base pressure of 350 Kpa... see if it gets to 550Kpa, then if you want to simulate injectors working in the mix add a 1mm hole bleed into a container and do same test, you can then play around and test pump current and voltage etc.(current would tell a lot...pump should go rated max current, under or over by too much and its no good)

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MY99 WRX EJ2.35L 720whp 9.48@147mph
https://youtu.be/c_lYEG0_Dyo

^sorry you're right I was dividing instead of multiplying the conversion doh!!

Nothing to see here!

But yeah it sounds very much like a dud pump or fpr.

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Bye bye betty blue. Hello F6.

There is a new walbro out now. Same size as the 450/460, but flows about 520. Uses more power though.

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Doing it for all the wagons out there

I've got full 12 gauge (4mm^2) wiring to the pump. I did some testing to the FPR by applying compressed air but I didn't simulate the flow as suggested.

I could do some measurements to the pump but I've decided to order the 450 Walbro next. I'm still not sure if I need a PWM controller for the pump as it could potentially flow too much at idle for the return line. Fuel heating could also be an issue?

I did some more googling and both the FPRs are knockoffs of the original Aeromotive 13101. But I've taken both apart and the machining work seems good. The system holds pressure for some time after the pump is powered down. I've heard that genuine FPRs won't hold pressure for a long time either since they are not designed to do that.

At this point I'm sure the problem is flow related, it's either the pump being lazy and/or the FPR leaking too much fuel the return line. What FPR would you recommend? Preferably something with two AN6 inlets.

So, I ran some flow tests for the fuel system. I disconnected the return line and routed it into a fuel canister. Then I ran the car for about 2 minutes and measured the fuel amount. I did not account for the fuel consumed by engine since it's not much of the total. I did the test with 3 Bar and 5 Bar fuel pressures. Here are the results:

258 lph @ 3 Bar (320 lph)
200 lph @ 5 Bar (263 lph)

Values inside the parenthesis are ones reported by the manufacturer.

At both pressure levels the flow is down about 20%. During the test the pump was seeing more than 13.5V at the terminals so it's not an electrical issue. Could be a bad pump or just too restrictive fuel lines (for the pump of this size). I haven't measured the pressure at the pump outlet but I suspect it would be higher.

This all combined with a china FPR which most likely is letting too much fuel through, lower pump voltage and heated fuel would explain the problems we had at the dyno.

Edit:
I also checked the pressure at the outlet. Pressure at FPR was 3 Bar. The gauge at pump outlet showed over 4 Bar. I've previously verified that gauge reads the same as the fuel pressure sensor. So that's over 1 Bar pressure drop between the pump outlet and the FPR. At slightly over 4 Bar, the pump should do 287 lph so actually it's not doing that bad.

Edit2:
Checked the pressure in the engine bay, right before the filter: 3,4 Bar. So that's a 0,7 Bar drop from the pump to the filter. The rest 0,4 Bar comes from the filter and fuel rails.

Attached Thumbnails

 

Wait u have a china fpr ...... bin that crap and get a genuine turbosmart 800 or 1200

Sent from my SM-G955F using Tapatalk

I have the Turbosmart 1200 with the two outlets. Works well easy to set up.

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Bye bye betty blue. Hello F6.

Most of the name brand FPR's work ok, Aeromotive, turbosmart, Sard, Tomei, Fuel lab, etc i have used with e85 well past 500hp and stock fuel lines, i would suggest though that is your serious about a competent fuel system you should be running a surge system/tank.....it will become big problem with a standard mounted pump.

I don't think fuel heating will be much of a issue with a single 450, in Australia we run 35-38 degree days on dyno with-out issue with fuel heating(with bigger pumps/multiple pumps even)....and even 40+ on street, if your worried put a cooler in return line.

4mm2 wire is only just good enough....how long is it, do the math.

Again your no where near the limit of your fuel lines, a lot of people around here used to run all day everyday 500hpatw with a old 255 walbro and 8mm line in subarus and nissans etc........and you'll never be with a 16g turbo

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MY99 WRX EJ2.35L 720whp 9.48@147mph
https://youtu.be/c_lYEG0_Dyo

Re the cable.

4mm^2 wire is very different to 4mm "auto" wire.

4mm "auto" wire is only about 1.8mm^2 cross sectional area. (About 16g sizing)



If its a genuine 4mm^2 wire it will be absolutely fine. If its a 4mm auto, then you should go up to a heavier gauge wire.

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Doing it for all the wagons out there

The wiring is an actual 4mm^2 cable. The FPR will be replaced this week. And as the surge tanks, I don't want to add complexity to the system if it's not absolutely necessary. I'm not sure if I'm ever to going run at such power levels that require the surge system. The car has to pass yearly inspection & emissions test.