bozzman

How much can I increase the boost PSI on my supercharger without rebuilding the stock engine, 4.6 DOHC? I currently running at 5PSI.

04mineralgreyGT

It depends on what DOHC 4.6 you have. The 03-04 cobras have forged bottom ends as well does the Mach 1 5-spd DOHC 4.6. Without a forged bottom end I would say 10-12 psi with an intercooler and a proper tune.

bozzman

Thank You. I have a 2003 Mach 1 with auto tranny. How do I increase the PSI? Pullies?

04mineralgreyGT

You don't have the forged bottom end with the auto Mach. But thats okay. Do you have a centrifugal s/c or a roots/twinscrew? Generally a smaller pulley with yield you higher boost #'s, yes. If you have a centrifugal you could look at an Anderson Ford Motorsport, UPR, or Steeda powerpipe (aka: boost pipe) and get another # or two of boost. I haven't seen any powerpipe for a twinscrew s/c other than what Kenne-Bell uses for their CAI (cold air intake). I think C&L Performance may have a CAI for a roots/twinscrew also. After looking harder at your original post I see you're running 5psi now. That leads me to believe you have a non-intercooled KB??? I would definately invest in an intercooler when you up the boost if the non-cooled KB is what you have.

Triisomy21

5-speed Mach's only come with a forged crank. Not rods, not pistons. Reason being is that the 4v likes to spin higher than the 2v.

bozzman

I have the Procharger with inter-cooler, P-1SC.

wwmost

max i would run is 10psi on stock internals. you can run a different pully to up the boost or get a boost pipe which should bring it up 1-2psi.

silverstang1996

you could run up to 15psi possibly beings that your s/c is a centri and not a roots/twin screw, those are the s/c's that really put stress on a 4v motor

Davojan59

i wouldnt run any more than 10 psi cause those mach 1 engines have high compression as it is so adding that much boost is not gonna do any good for it. Not to mention its a hard to tune a high compression car with a blower added.

04mineralgreyGT

If you have a Procharger P1-SC you should already be at 8 psi. The P1-SC kit with intercooler is an 8psi setup. I've never seen one with less than 8 psi anyway.