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Old 08-17-2012, 02:05 PM   #1
simenad
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Default Adjust FPR, more fuel?

Is it possible to adjust the FPR so the engine get's more fuel? Without mapping it? Or would I ruin the map and the original levels?
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Old 08-17-2012, 07:58 PM   #2
the suicidal eggroll
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No. If you were to crush the FPR or otherwise increase the fuel pressure, it would initially make the system run richer than target, which would cause the closed loop system to lower your long term fuel trims to pull all of that fuel right back out. In the end, the only thing you would be doing is making your AFR Learning more negative, as well as increasing the load on the fuel pump, reducing its capacity.
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Old 08-18-2012, 12:41 AM   #3
lukeskywrx
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What MAF? -Speed Density!

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Injectors flow more fuel at higher pressure but pumps flow less, if you can get enough pump flow at high pressure you can get more fuel in the cylinders. If your baseline pressure is too high you will hit the min .6ms base pulsewidth and run rich at idle.

All about give and take.
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Old 08-18-2012, 12:51 AM   #4
the suicidal eggroll
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Quote:
Originally Posted by lukeskywrx View Post
Injectors flow more fuel at higher pressure but pumps flow less, if you can get enough pump flow at high pressure you can get more fuel in the cylinders. If your baseline pressure is too high you will hit the min .6ms base pulsewidth and run rich at idle.

All about give and take.
That's all fine and dandy, except the OP said "without mapping it". If you don't tune for the increase in fuel flow, you'll just run richer than target, which will cause the closed loop system to pull everything back out via AFRL.
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Old 08-18-2012, 05:04 PM   #5
lukeskywrx
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What MAF? -Speed Density!

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Missed that bit, To OP don't be stupid tune your fuel if you change any fundamental constants in engine operation.
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Old 08-23-2012, 06:34 AM   #6
ride5000
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Quote:
Originally Posted by the suicidal eggroll View Post
That's all fine and dandy, except the OP said "without mapping it". If you don't tune for the increase in fuel flow, you'll just run richer than target, which will cause the closed loop system to pull everything back out via AFRL.
well, ultimately, that would buy you a bit of IDC headroom.

so it's not totally pointless...
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Old 08-23-2012, 08:01 AM   #7
jkopinga
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^^^ It's sort of true but in terms of drivability it wouldn't be THAT nice on CL to OL transitions, etc. I would AT LEAST change scalar and latencies so that the higher Fuel Pressure is applied in a proper manner not affecting the rest of the tune.

Jasper.
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