LT1 fuel pressure

[Everett Vassar]

What is optimum fuel pressure for LT1 ? I haven't learned how to lengthen or shorten injector duty cycle with the laptop yet, but I guess I can make some rich/lean adjustments with fuel pressure?

[Ed Wright]

From the factory: 45 to 47 psi, with the vacuum hose off the regulator, & at WOT.

[Dan Fahey]

Originally Posted by Ed Wright

From the factory: 45 to 47 psi, with the vacuum hose off the regulator, & at WOT.

Mine is 38 to 43psi with vacuum hose!
Using LS1 Injectors.

D

[Ed Wright]

Originally Posted by Dan Fahey

Mine is 38 to 43psi with vacuum hose!
Using LS1 Injectors.

D

Dan, I know you are a mechanic, so I'm going to explain it.
Should be no manifold vacuum @ WOT, therefore, WOT with the vacuum hose connected is the same as testing in the shop with the vacuum hose removed from the regulator. I have had many LT1s through my shop, and don't remember seeing one with only 43 psi. Maybe your gauge, or you have a Walbro pump?

And Pure Stock rules allow different injectors?

My LT1 car has 60 psi.

[Dan Fahey]

Originally Posted by Ed Wright

Dan, I know you are a mechanic, so I'm going to explain it.
Should be no manifold vacuum @ WOT, therefore, WOT with the vacuum hose connected is the same as testing in the shop with the vacuum hose removed from the regulator. I have had many LT1s through my shop, and don't remember seeing one with only 43 psi. Maybe your gauge, or you have a Walbro pump?

And Pure Stock rules allow different injectors?

My LT1 car has 60 psi.

I had LT1 Injectors and replaced them with 24lb LS1’s.
IHRA tech went over the car several times and passed inspection.
They are a direct replacement using same Stock Fuel Pressure.
Using a Bryan Herter high test tune and seems to work fine.
Though could use a good Dynoing with current PS cam.

Still using ODB1 and TunerCat to make little changes.
Using high pressure Walbro Fuel Pump and adjustable Fuel Pressure Regulator.
Set the pressure range from 38/43 psi which is the Stock setting.



Dan

[Rich Biebel]

I ran my LT-1 stocker with 50lbs of fuel pressure and at that time ran 24lb Accel injectors. It went 10.50's in real good air at 125 in the then separate A/FIA class.....Car was about 200 lbs over the weight minimum for the class....


After selling the car I was given the opportunity to drive it again for 2 weekends. It still was run with around 50lbs of fuel pressure and had bigger injectors. It was a little heavier than when I ran it and ran 10.50's in real good air.....running B/SA.....It had a better engine and much better fuel map tune up. The car ran some 10.20's at Atco before the HP was hit a while later.