Adjustable Fuel Pressure Regulator?

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RawbDidIt

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Flow rate increases with the square of pressure. I was on the edge of too little fuel and bumping the pressure gave me a margin of extra fuel.
Interesting, I appreciate the explanation... I imagine this only makes a difference if you increase air flow as well, right? Otherwise the ECM wouldn't use the additional flow rate available because the AFR would still be maintained at stoich. I would also imagine that the additional airflow necessary to require something like this would be forced induction rather than a simple cold air intake. More fuel only means more power if there's more air, does this fuel system need additional flow rate at WOT at high RPMS when air flow is maxed, or is this useless to a mostly stock engine with a couple of bolt ons? Curious as I prepare for a 383 upgrade when I may be increasing air flow through the engine due to displacement.

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JayMB

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What L31MaxExpress was getting at is that if you need to get a little bit more fuel out of stock injectors you can do it by upping the fuel pressure. Vortec trucks already run the injectors around 58 PSI. The 19 LB/hr injectors these trucks come with are inadequate for much more than stock power. A better solution would be to buy better injectors, and swap to an intake manifold that takes normal MPFI injectors.

Other than the intake plumbing and free flowing exhaust - Nothing matters unless you get a tune. Especially on these Vortec trucks, a mail order tune is probably the best performance bang for your buck you're going to get.
 

Schurkey

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Flow rate increases with the square of pressure.
Yes...and no.

If you're talking about fuel pumps, the gallons-per-minute is highest at "free-flow", essentially zero pressure. As the pressure goes up, the gallons-per-minute decreases substantially.

If you're talking about fuel system plumbing, or injectors, then yes--the gallons-per-minute increases with increased pressure.
 

RawbDidIt

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Yes...and no.

If you're talking about fuel pumps, the gallons-per-minute is highest at "free-flow", essentially zero pressure. As the pressure goes up, the gallons-per-minute decreases substantially.

If you're talking about fuel system plumbing, or injectors, then yes--the gallons-per-minute increases with increased pressure.
Ok, that makes sense that the injectors flow more with additional pressure, but does it really matter based on the upgrades the OP mentioned? I have a hard time believing that the fuel system is hampering the power in these engines, i was under the impression the biggest performance bottlenecks were regarding air flow and exhaust. From what I've heard a CAI and a tune don't really do that much with those areas. the headers help more, but is it enough to really make use of the additional fuel flow that may be available from increasing pressure to the injectors? Besides, if that really is the formula, 10 lbs of pressure on top of 60 lbs already doesn't sound like it would yield that great of results.

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Supercharged111

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Ok, that makes sense that the injectors flow more with additional pressure, but does it really matter based on the upgrades the OP mentioned? I have a hard time believing that the fuel system is hampering the power in these engines, i was under the impression the biggest performance bottlenecks were regarding air flow and exhaust. From what I've heard a CAI and a tune don't really do that much with those areas. the headers help more, but is it enough to really make use of the additional fuel flow that may be available from increasing pressure to the injectors? Besides, if that really is the formula, 10 lbs of pressure on top of 60 lbs already doesn't sound like it would yield that great of results.

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Tune was the first thing I did. Even on an otherwise bone stock truck it's a significant difference.
 

PlayingWithTBI

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Vortec trucks already run the injectors around 58 PSI. The 19 LB/hr injectors these trucks come with are inadequate for much more than stock power

19LB/HR injectors run @ 58PSI will flow 21.9Lb/Hr and support 332HP. At 70PSI they will flow 24.1Lb/Hr and support 364HP, according to the EBL Utility App if that helps any...
 

Awest623

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19LB/HR injectors run @ 58PSI will flow 21.9Lb/Hr and support 332HP. At 70PSI they will flow 24.1Lb/Hr and support 364HP, according to the EBL Utility App if that helps any...
Just to note. Those hp numbers don't include power enrichment either. So subtract another 20-25% on the hp.

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