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larger injectors question


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6 replies to this topic

#1 baccaruda

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Posted 03 October 2003 - 04:33 PM

If I install larger injectors on an EA82T for more fuel at high boost, will they be giving more fuel all the time or just when needed? does the car send an on-off signal to it or will it progressively increase the amount until it's getting as much as needed?

#2 MilesFox

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Posted 03 October 2003 - 06:33 PM

something about bosch L-type injectors, somethimg about injectors on nissan z-cars will work. look into that
i dont know specifically, but i read something about it a time ago

#3 Skip

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Posted 03 October 2003 - 06:57 PM

Andy, please spend your money on an A/F ratio gauge (meter).
Then, if you see a lean condition at the boost you are running, think about larger poundage injectors.
I run 14 -15 psi daily and have never seen a remotely lean condition when on boost. Always very rich (on twin meters I have currently connected for calibration purposes).
Subarus are way over engineered in many aspects of performance.
Most notably the fuel delivery system.
Just one man's real life experience.

#4 ramperf

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Posted 03 October 2003 - 07:22 PM

If you put larger(more lbs per hour) they will flow more lbs per hour all the time. Pulse time is controlled by the ecu. You can increase pulse time by turning up the fuel pressure. This will richen up the mixture.
Ron

#5 Skip

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Posted 03 October 2003 - 07:40 PM

Ron please reread what you just said
"You can increase pulse time by turning up the fuel pressure. This will richen up the mixture."

Don't you mean increase the flow rate?

The ECU will "tick tock" faster I believe with a higher fuel pressure or larger injectors. This is only when it is not thinikng the engine is on boost.
(hot wire MAF info)
My observations have been that the ECU does NOT know the engine is at a positive intake manifold pressure. (The pressure switch only lights the dash light, I've had it unpluged). It goes into it's full rich map, ignoring the 02 sensor, when certain parameters are met. Engine temp, RPM, TPS reading and vehicle speed are involved.
Please tell me if you know different from my empirical observations

#6 baccaruda

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Posted 03 October 2003 - 09:00 PM

thanks guys.
skip, thanks for the push toward an a/f meter first.. i would intend that actually but since i had the fuel injector Q in mind now my brain spit it out. a lot of the ausubaru guys upsize their injectors but many of them put on bigger turbos as common practice too :P

#7 Adam N.D.J.

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Posted 04 October 2003 - 02:24 AM

Actually, if you put larger injectors in there, they WILL flow more, BUT, the computer will compensate once it see's that it's running too rich, lowering the pulse width of the injectors, and leaning out the mix. Once you get into boost, the computer goes into a default loop, and in some systems tunes out the O2. So when you went into boost, your larger flow injectors will dump in more fuel than stock, and you'll prolly run way richer than normal (at same boost levels as stock). So you can compensate this richer mix by adding more air (more boost). The problem is finding larger injectors that will work. Ours are held in differently than most systems, and use rubber hoses instead of a snap lock to connect the injector to the rail. Although if you get creative, you won't have a problem getting around this. Anyways in summary, if you keep off the boost, you'll have basically the same fuel mileage, but once you hit boost, you'll be able to watch your fuel gauge drop. Lotsa Luck.




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