The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)

- Engine & Drivetrain (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=24)

- - 383 Fuel Pump? (https://67-72chevytrucks.com/vboard/showthread.php?t=776680)

CPride

12-04-2018 11:17 PM

383 Fuel Pump?

I have a side project...a 69 land cruiser with a fuel injected 383 Chevy. Trying to figure out how to calculate the fuel pump psi..or should I just go over and put a regulator? If so what psi should it be set at? Any help or clues to figure it out would be sorely appreciated.:metal:

mongocanfly

12-04-2018 11:28 PM

Re: 383 Fuel Pump?

What type fuel injection you have?...better to be over and control with a regulator

CPride

12-05-2018 03:59 AM

Re: 383 Fuel Pump?

HERE are the two on it now.

mongocanfly

12-05-2018 05:09 AM

Re: 383 Fuel Pump?

Youll need something capable of 85pph and 21psi.....according to the specs

CPride

12-05-2018 10:45 AM

Re: 383 Fuel Pump?

Thanks but that's not entirely true. 60 PPH@12 PSI 85 PPH@21 PSI

To quote a Holley rep when I asked this question:

Quote:

depends on application, the injectors are designed to work with a factory GM style fuel system for 90-95 pickups, so 11-12 PSI, but the injectors can handle up to 21-22 PSI. It depends on how much flow your horsepower needs dictate.

So therein is the question. How much flow does a 383 need?

mongocanfly

12-05-2018 11:14 AM

Re: 383 Fuel Pump?

Gotcha....the holley rep wouldnt recommend one ?

weq92f

12-05-2018 02:37 PM

Re: 383 Fuel Pump?

22psi doesn't sound high for FI. Just run a pump into a regulator then adjust to your engine's needs.

My big block with 4 80#/hr injectors runs happily at a regulated 35 psi on a return line system.

Hth,

-klb

Captainfab

12-06-2018 12:21 AM

Re: 383 Fuel Pump?

I think first you will need to come up with an approximate HP number that the 383 is developing. Then the necessary fuel flow can be calculated.

https://fuelinjectorclinic.com/hp-calculator

B. W.

12-09-2018 05:56 PM

Re: 383 Fuel Pump?

You need to know the approximate HP of your engine. Use a program like desk top dyno or the Comp Cams calculator. Then you can calculate your fuel pressure based on injector size.

If you are running a modified GM TBI setup you will need the ECM tuned or run a program like Tuner Pro so you can tune it yourself. If you run Tuner Pro it has a utility that you can plug your #s into & play with different fuel pressures.

For example, I have a 383 with a big block throttle body & 80# injectors, my fuel pressure is set at 22 psi. This setup will support 393 HP. Obviously, if you have a 200 horse motor & run 80# injectors at 22 psi you will be over fueling. That's why it's important to know your approx. HP.

(What Captainfab said, just more words!)

Here's a link with a lot of info:

https://www.dynamicefi.com/Tune_Intro.php

All times are GMT -4. The time now is 03:21 AM.