Recommended Fuel Pressure?

[JCampbell]

New engine for my Suburban, trying to tie up some details.

Fresh L31 Vortec longblock, internally stock. Fresh 5.7 injectors. Ultimate'd throttle body. Mercruiser TBI intake, Thorley tri y's w/ Y pipe.

Looking for reccomendations on fuel pump and FPR spring. Not certain on what pressure I should be looking for. 14? 16? 18?

[Chewy1576]

When you say 5.7 injectors, I assume you mean 60 lb/hr injectors? An 18 psi spring will be a small bump in fuel pressure, without supplying too much fuel.

What year is the Suburban? An EP381 pump will supply more than enough fuel to provide 18 psi and is a direct replacement in the TBI trucks and it came stock in Vortec trucks also.

[JCampbell]

I'm assuming they are the 60#/hr injectors. I haven't pulled them yet to verify.

Sub is an 88 K20.

I appreciate the info.

<a href="http://s151.photobucket.com/user/JasonCampbell1180/media/My%20Trucks/24X625011.jpg.html" target="_blank"><img src="http://i151.photobucket.com/albums/s160/JasonCampbell1180/My%20Trucks/24X625011.jpg" border="0" alt=" photo 24X625011.jpg"></a>

[Fast355]

New engine for my Suburban, trying to tie up some details.

Fresh L31 Vortec longblock, internally stock. Fresh 5.7 injectors. Ultimate'd throttle body. Mercruiser TBI intake, Thorley tri y's w/ Y pipe.

Looking for reccomendations on fuel pump and FPR spring. Not certain on what pressure I should be looking for. 14? 16? 18?


I would use the 1992-1994 4.3 W CPI Astro pump. Along with an external regulator. Would try around 20 psi with the stock 61 lb/hr 350 injectors.

Kinda doubt you will like the stock L31 cam in that setup.

[Hog]

I would use the 1992-1994 4.3 W CPI Astro pump. Along with an external regulator. Would try around 20 psi with the stock 61 lb/hr 350 injectors.

Kinda doubt you will like the stock L31 cam in that setup.

What did the 5.7 Vortec/TBI marine engines run for injectors and at what fuel pressure?
I agree with your fuel pump recommendation, its the EP381 which was also used on the 1996-97 Vortec 4.3/5.0/5.7/7.4 and the GMC turbocharged 4.3 trucks 1991 Syclone and 1993 Typhoon.
That's the same pump that Chev Performance Parts recommends for their Ramjet 350(351hp@5000rpm/403lb/ft@3600rpm and Ramjet 502(502hp@5300rpm568lb/ft@3600rpm/Ramjet 454-ZL1(510hp@5750rpm/493lb/ft@4250rpm) crate engines.
Certainly enough fuel for a TBI Vorec engine.

peace
Hog

[Fast355]

What did the 5.7 Vortec/TBI marine engines run for injectors and at what fuel pressure?
I agree with your fuel pump recommendation, its the EP381 which was also used on the 1996-97 Vortec 4.3/5.0/5.7/7.4 and the GMC turbocharged 4.3 trucks 1991 Syclone and 1993 Typhoon.
That's the same pump that Chev Performance Parts recommends for their Ramjet 350(351hp@5000rpm/403lb/ft@3600rpm and Ramjet 502(502hp@5300rpm568lb/ft@3600rpm/Ramjet 454-ZL1(510hp@5750rpm/493lb/ft@4250rpm) crate engines.
Certainly enough fuel for a TBI Vorec engine.

peace
Hog

46 lb/hr injectors with a 30 psi regulator.

[Hog]

46 lb/hr injectors with a 30 psi regulator.

Thanks Fast, much appreciated.

peace
Hog