changolocs85

hey fellow mustangers, ive been a member here for over 3 years and mostly just lurking, never really had any input, or questions. actually ive been no help at all, haha. but i got a question for all you gear heads. i know our stock bottoms (2v 4.6l PI) are reliably good until about 400 rwhp with a supercharger. i also know that extra power is due to pressure buildup (boost) in the cylinders. Well my question is if i get better flowing intake accesories, and heads and cams, with a supercharger, my rwhp will go up but not do to overpressure but due to better flowing air delivery. Now if my thinking is correct shouldnt the bottom ends reliably support more than the 400 rwhp we all became used to... or am i just rambling here? by the way little useless info bout me since ive never introduced myself, i have a 2000 gt with a auto pretty much stock except for CAI, shortys, o/r x cat back, and a predator tuner. thanks for any input, hopefully this deployment gives me the money my mustang needs.

Rockwell28

ive always heard that the limit was 450hp never got clarity on if that was 450rwhp or 450 crank hp. But same is said for the 4.6 3v and the 4.6 dohc non termi motors but clearly with the 3v and the dohc 4.6 ppl have ran more power through them and it would seem that its bc of the better flowing heads, cams etc or combination of the two and if its breathing better bc of those factors then the boost is causing less stress on the internals of the shortblock. Just like going with blower cams on a 2v there is a power boost but the cams are helping the engine breathe better therefore causing less stress on the internals and add better flowing heads to that combo the that will also in theory help the breathing out a bit and in return cause less stress on the internals. I was wondering the same awhile back and asked on a different forum and I was told the same a big limitation in that 450 hp number is the factory heads and cams and by changing that you give yourself a bit of leeway above that 450hp bc your not just reaching that number on boost alone you increased the efficiency of the motor with cams or whatever so the numbers will go up without alot of boost and alot of boost causes more stress. Hope that makes sense im gonna stop there bc the paragraph is getting kinda big. Im sure others will chime in on this subject.

Rockwell28

Btw good luck on that deployment stay safe shoot, move and communicate!!!

changolocs85

thnx rockwell for the deployment advice, i dont have much longer here, alot of close calls, but all in a days work. but back to the question at hand. everybody says that horsepower breaks motors, but from ive learned in my years its pressure that breaks them. cuz ive also noticed 8 pounds of boost gets you pretty much to 400 hp, but if i throw better flowing intake parts on the vehicle, my horsepower would increase, but with the same pully, the boost will drop, cuz i thought boost was a set increase in pressure caused by the predetermined flow capabilities of the engine. so im thinking maybe 8 lbs of boost is the limit of our engines not 400-450 hp

Rockwell28

there are a few ppl running 9-10lbs on the stock engines. and yea boost is kinda a measurement of restriction thats why you have the increase in power but the drop in boost pressure I could be wrong though. But a few ppl will say dont go over 10psi on a completely stock motor.

mrtstang

It's a combination of things like hp/tq, psi, detonation, rpm, etc...

foru2nv4

from what I understand our cars with the 4.6L SOHC can handle up to 16psi of boost and if you go past that you might blow engine. so if you stay under that 16 you will be okay. I been running my SC at 13psi of boost for over two yrs now have had no problems with engine blowing.

mrtstang

What's your rwhp with 13 psi? I don't think you'll find too many stock 4.6 SOHC motors running 16 psi. I would definitely not recommend it.