I am thinking about converting my 96 over to the Ls1 engine management. From what i understand the Ls1 uses a constant 58 pounds of fuel pressure. Lt1's use a vacuum operated 43 pounds of fuel pressure. What fuel pressure regulator would be needed to get the constant 58lbs of pressure without a vacuum port. This Ls conversion seems to be really cool deal. I just want to figure out all i would need before i start spending cash.

 

How about deal with things in programming rather than overcomplicating the fuel system.

 

I recommend against the Aeromotive adjustable FPR. Search here and you'll find lots of other negative feedback on it.

As already mentioned, you could tune to use the LT1 FPR, and not worry about replacing it. Or find another adjustable unit.

 

The only thing the PCM has to know is the flow rating of the injectors. It has no way of knowing what the fuel pressure is. If all you are doing it running an LT1 engine with an LS1 PCM, you don't have to change the fuel pressure to 58psi. If you wish to delete the vacuum compensation (which makes sense), you can do that by simply removing the vacuum reference line from the FPR.

 

Thanks Injuneer. That makes sense. Thats kinda of what i was looking for. I just thought it would be convenient to run at 58 psi so i wouldnt have to go to a bigger injector when i do my AI heads and cam.

 

Just get the constant set correctly in the PCM with whatever pressure you go with. When using an adjustable on an LT1 this is what I would do to calculate a new constant. Something to think about when doing the swap. I am sure something similar is needed for the LS1 PCM.

"The fuel injector constant is affected if you run a fuel pressure different than the stock 43.5psi. If you do, divide your new pressure by 43.5 and take the square root. Then multiply that number by your fuel injector's rating. So, for stock 24# injectors running at 60psi of fuel pressure, you'd do 60 / 43.5 = 1.379; then sqrt(1.379) = 1.174; then x 24 for a new injector constant of 28.18. What you are doing is telling the PCM you have the equivalent of larger injectors that flow more, so they won't be pulsed as long (as the higher fuel pressure is a "replacement")."