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Discussion Starter #1
After reading some of the posts here, I'm kinda convinced that FMU + our returnless fuel system might not be a very reliable combo.

However, will our stock fuel system more than sufficient in delivering fuel for additional injector? Since the additional injector duty cycle will over lap the stock injectors, at high boost, will it cause a problem?

What are the costs and skills involved in making a return fuel system + fuel rail upgrade? Is it highly recommended if I want to go PFC + larger injectors in the future?

BTW, I've a 1zzfe Matrix. And I'm not planning for mad boost, but at least driving daily at 7-9psi.
 

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ztan said:
After reading some of the posts here, I'm kinda convinced that FMU + our returnless fuel system might not be a very reliable combo.
Based on what? What posts are these?

The guys with the SF FMU have had the easiest time tuning...

Anyways you are better off just going bigger injectors and PFC than you are trying to make the 5th injector work right.
 

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I was kinda wondering on this too, do you think the pfc has made the return fuel system conversion kinda pointless for our cars, or is there still a point where it would be needed, as in, do you think there is a flow or hp level that would require a return fuel system?
 

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Discussion Starter #4
It was a post titled "SF fuel system revisited".

it is also partly due to my perception that FMU is a "squeezer" on the fuel line, and in a returnless fuel system the high pressure part of the fuel line might starve out of fuel quickly since it is not a circulating and continuous system.
 

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the only part of my fuel system that is the same as an fmu is that it raises fuel pressure with boost .so the result is the same however the system is completely selfsustained in it dosn't require an exsiting return fuel system to operate so far i have made just under 300hp to the wheels on a stock 1zz w/stock fuel system and my fuel kit on 15psi.at this point it still wasn't lean but we didn't wont to break a motor since it was completely stock .
 

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hmm.... so the best thing to do might be to watch fuel pressure with the existing system and watch a/f, and if the pressure drops too much might be time for a differant setup...

So you got 300 horse with the stock pump also? maybe the single line would be fine for almost anything with a 255 lph pump then.
 

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did not know that....

now I do
 

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It also has a self contained return system of sorts which is part of why it doesn't have problems.

Its really a pretty slick design. I hated the idea at first too (you can look back about 6 months and I was seriously wary about it) but now that I've had a chance to work with it I think its a pretty good solution really. Still not as elegant as a power FC but for the price I think it does a good job.
 

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Even for a serious turbo system you don't need to mess with the stock fuel lines and rail. We still have 100% stock parts from the tank to the injectors in our MR2-S. You do need a way to raise pressure with boost. The SF unit does this, as does the adjustable boost referenced regulator that we used to replace the stock regulator in our car. Along with the bigger injectors and higher flow fuel pump this setup has been working great. We're approaching the limits of the 550's unfortunately, so bigger injectors will be going in when we tune it for over 400whp.
 

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monkeywrench said:
Even for a serious turbo system you don't need to mess with the stock fuel lines and rail. We still have 100% stock parts from the tank to the injectors in our MR2-S. You do need a way to raise pressure with boost. The SF unit does this, as does the adjustable boost referenced regulator that we used to replace the stock regulator in our car. Along with the bigger injectors and higher flow fuel pump this setup has been working great. We're approaching the limits of the 550's unfortunately, so bigger injectors will be going in when we tune it for over 400whp.
Must be nice ;)
 

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Originally posted by monkeywrench
Even for a serious turbo system you don't need to mess with the stock fuel lines and rail. We still have 100% stock parts from the tank to the injectors in our MR2-S. You do need a way to raise pressure with boost. The SF unit does this, as does the adjustable boost referenced regulator that we used to replace the stock regulator in our car. Along with the bigger injectors and higher flow fuel pump this setup has been working great. We're approaching the limits of the 550's unfortunately, so bigger injectors will be going in when we tune it for over 400whp.
:drool:


What size is available larger than the 550? I haven't seen any adveritised anywhere.

EDIT: Post # 500 !!!!! whore!!!
 

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Liqquid said:
:drool:


What size is available larger than the 550? I haven't seen any adveritised anywhere.

EDIT: Post # 500 !!!!! whore!!!
Common sizes are 650 720 850 1000 1200 etc. But you can get almost any size custom
 

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Boosted2.0 said:
Common sizes are 650 720 850 1000 1200 etc. But you can get almost any size custom
The trick is getting them to fit the 1zz head and to work with the PFC. We'll post results once we get them working. So far not many people need to go bigger than 550cc but many are working in that direction.
 

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monkeywrench said:
The trick is getting them to fit the 1zz head and to work with the PFC. We'll post results once we get them working. So far not many people need to go bigger than 550cc but many are working in that direction.
Whats hard about that? Are those injectors a non standard impedence or something?
 

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good question, I know the 2zz uses "high impedance" injectors that will not fit the 1zz.....

and I know that when it comes to nitrous setups none of the "NOSsle" or NXL kits will work (ones that put a plate beneath the injector)... not sure if that is related to the injector or clearance.

all of the above you probably already knew!!
 
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