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The mkiv Supra Owners Club

Fuelling A Rail


terribleturner
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What are peoples thoughts on a fuelling system that feeds either end of the rail with it's own pump?? I was thinking a of a system that would Y both pumps together and then Y them back off at the rail. Anything that people like or don't like about the each pump for each end idea??

you can do it either way. i personally have gone for dual lines using 6an ss hose. if you go the single route just make sure you use a big enough hose like 8an.

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I have three pumps and two lines/ tripple hanger:drool:
:shrug:

 

 

 

James,

Why do you need two pumps? Are you going bigger than T67?

What would happen if one pump fails?

I'm going to kit it simple with 1x Walbro, PE650 injectors, stock rail, stock FPR, no FPD Bypass.

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:shrug:

 

 

 

James,

Why do you need two pumps? Are you going bigger than T67?

What would happen if one pump fails?

I'm going to kit it simple with 1x Walbro, PE650 injectors, stock rail, stock FPR, no FPD Bypass.

 

hes got a T66. i think a 67 would be borderline on one pump

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Has anyone actually measured any fuel pressure drop off, which they've managed to directly attribute to the pump not being able to supply enough volume of fuel?

 

Not exactly, but when we first put the single on my car, (T67 with PE650's), I had two maps done for my E-manage. The race fuel map was set-up at 1.8 bar of boost, and the fuelling showed no signs of dropping off. (I'm purposely not quoting any power figures ;) ).

However, at TOTB last year my pump started to die and couldn't flow enough fuel to keep up with 1.7 bar. It was immediatly apparent there was a problem as car was running lean after 4krpm. No matter what fuelling adjustments I made, it would still run lean. After changing the pump, all was well again. (well, it wasn't, 'cause I'd adjusted the E-manage to chuck more fuel in, so it's initial run was stonkinly rich!).

So whilst there's no actual measurements taken, it can be fairly obvious.

 

Edited to add, you could also see the fuel pressure increasing as boost increased to a point, then the fuel pressure started to drop off as the pump couldn't keep up...

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I heard from several people now that 2 pumps isn't neccassary, but i'm also thinking that if i am pussing it and that ONE pump goes on me, if i go dual i will still have the 2nd to get me home.

 

Im gonna put either 720's or 780's in the rail and have the 2nd pump come on on full boost (or when it feels it's needed).

 

So there's nothing wrong with having 2 pumps with their own lines and fuel filters to either end of the rail?? It's just not a way i have read about yet and just want some clarification.

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but isn't there a danger that if the car is set up for two fuel pumps and one fails the mixture might well go very lean, very quickly?

 

I'm sure I remember a discussion about this once. Think it was Ian or Dude.

Correct. At least if one pump fails, the car just stops, not melts.

 

Obviously if you are going for BIG power, (600+++), then yes you need two pumps.

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