The HPP Racing tune that wasn’t a tune at all

[97SWBCHEVY]

That is a FMU, fuel management unit. They came in various forms. Some increase the pressure 1:1 with boost, others are 2:1, 3:1, 4:1 even seen 6:1. I ran one combined with a MSD Boostmaster timing box on my Weiand 177 supercharged TBI 350 years ago since the ECM was blind to boost. I had a 4:1 unit, at 10 psi boost my fuel pressure was 50 psi and at idle and out of boost the fuel pressure was the stock 14 psi.

Well alrighty then, thank you for educating me on this! Would I be correct in thinking I should bypass this and run my few lines direct like they are normally? This FMU set up was operating off of vacuum that was coming directly from the plumbing for the supercharger and the intake, I just have the one coming off the super charger plugged off…so I doubt it pulling the correct amount of vacuum to increase or change in the fuel pressure…