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-   -   FI Duratec fuel requirements (http://www.focusfanatics.com/forum/showthread.php?t=289079)

sporadic 05-31-2012 12:23 PM

FI Duratec fuel requirements
 
I've asked around, used some calculators, but I can't get a straight answer.
I currently have 55# injectors, stock returnless fuel system and it works perfectly at 220whp (approximate).

At what point should a BAP be added? When should I make the jump to 80# injectors? How about ripping that out for a return style system?
The (max) goal of my next build is 25psi on a D20 with a GT2871R. That should be right around 400whp judging by dynos I have seen.
I've been told the 55# injectors and a BAP will be sufficient for 400whp. I've also seen where CFM is trying to sell a 300whp kit that includes 60# injectors and a BAP. Seems overkill if the previous statement is accurate.

Pardon my rambles. Lots on my mind planning the build.

1turbofocus 05-31-2012 02:14 PM

I would add the 60lb and watch the fuel psi , if you see it dropping then add the BAP , My opinion is to add the return system about 350HP for safety

Tom

sporadic 05-31-2012 02:31 PM

Quote:

Originally Posted by 1turbofocus (Post 4192770)
I would add the 60lb and watch the fuel psi , if you see it dropping then add the BAP , My opinion is to add the return system about 350HP for safety

Tom

What is the main benefits of going return style vs. just bigger injectors like 80lb?
Edit: OK so I have learned that general fuel control is simplified with a return style with less ramp-up in fueling.

At the moment I'm assuming the maximum output of the stock fuel pump is what is the limiting factor when we're talking about moving to a return-style system.
At some point the stock fuel pump just can't flow anymore, regardless of injector size. THAT is when I figure a return style fuel system is required.

1turbofocus 05-31-2012 06:13 PM

You are correct , its the fuel pump not the Injectors

Idealy you want 1psi fuel psi fro each psi of boost with base fuel at 41psi , so 10psi boost you would want 51psi fuel , this is hard to do with the tuning software we have to use and the returnless fuel system , so what happens is as you go up in boost the injectors do x amount of dutycycle as the fuel psi falls off the dutycycle goes up to make up for the loss/lack of fuel psi to maintain A/F this is why it is best to always run larger injectors then needed because you burn up a lot of injector dutycycle just from not having enough fuel psi

With a return system you put a Vac line on the fuel psi regulator so every psi of boost adds 1 psi of fuel psi , makes life easier

Tom

sporadic 05-31-2012 08:30 PM

Quote:

Originally Posted by 1turbofocus (Post 4193123)
You are correct , its the fuel pump not the Injectors

Idealy you want 1psi fuel psi fro each psi of boost with base fuel at 41psi , so 10psi boost you would want 51psi fuel , this is hard to do with the tuning software we have to use and the returnless fuel system , so what happens is as you go up in boost the injectors do x amount of dutycycle as the fuel psi falls off the dutycycle goes up to make up for the loss/lack of fuel psi to maintain A/F this is why it is best to always run larger injectors then needed because you burn up a lot of injector dutycycle just from not having enough fuel psi

With a return system you put a Vac line on the fuel psi regulator so every psi of boost adds 1 psi of fuel psi , makes life easier

Tom

That does sound simpler to tune for. Know where I could find a list of parts necessary to convert to a return system?

1turbofocus 05-31-2012 08:52 PM

Fuel cell , lines , fuel psi regulator , fuel rail

Tom


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