question for my supercharged 4.6l

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04-22-2006, 03:17 PM

#11

2000GT4.6

6th Gear Member

Join Date: Jan 2004

Location: United States

Posts: 12,575

RE: question for my supercharged 4.6l

Quote:

ORIGINAL: stang869846

lol (2000gt 4.6) the 96-98 gt's NPI cars have a 9.3:1 or 9.4:1 compression ratio stock i cant remember the newer 99-04 gt's compression ratios but i know for a fact it is not lower then that and if it is its not by that much. just to let u know. but thanx for ur input though. oh yea and roaddog i mentioned earlier that i am gettin me a new shortblock in 2-3 months i know the stock pistons and rods are **** but thanks some people probably dont knw that. and yoteehunter ur saying if i use .090 thickness on the gaskets i would be running the same compression ratio as before? if thats true then that sounds like a plan. thanks to all that replied i cant wait to see what she puts down after i get this done. and for the PI headswap its pretty much straight forward? any little things i need to look for if anyone in here has done em' just makin sure before i do the swap.
thanks
chris

You will increase your compression swapping to PI setup on your stock shortblock. Adding this with 12 psi will not be a good thing.

Honestly, do you have a accurate boost gauge? I have never heard of even a NPI setup living for very long at 12 pounds of boost. and 310 RWHP sounds pretty low for 12 PSI as well. Even with the crappy NPI heads you should make more than that at 12 pounds.

Regardless, the stock rotating assembly on a PI 4.6 won't last long on 12 psi, if it even makes it past the first dyno pull. A NPI shortblock with a PI swap and 12 psi won't even make it thru the first dyno pull more than likely.