To PI or not to PI?
04-24-2007, 07:16 PM
#1
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To PI or not to PI?
As some of you might know, I'm building a V8. I have a Teksid block and a NPI intake so far, and I've been pretty much building off of used parts. The only major spendings I'm counting on will be the 5.0 stroker internals and a T-56, preferably Viper Spec. Now there's a guy in my town selling a set of NPI heads with all the guts for $100. Would they flow as well as PI heads if I had them ported? Note: The NPI intake I have is plastic and therefore can't be ported.
OR would it be more cost effective to just wait for a set of PI heads and buy the intake he's also selling? Keep in mind he's also selling a PI blower...but I can always get an adapter for that if I went NPI.
The objective of the car is to be an open-track toy, not a drag car, so a rediculous amount of horsepower isn't necessary.
OR would it be more cost effective to just wait for a set of PI heads and buy the intake he's also selling? Keep in mind he's also selling a PI blower...but I can always get an adapter for that if I went NPI.
The objective of the car is to be an open-track toy, not a drag car, so a rediculous amount of horsepower isn't necessary.
04-24-2007, 07:22 PM
#2
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RE: To PI or not to PI?
i would definetly go PI heads because as crappy as stang heads flow, the PI makes it a little better. if you have the money, id just get some VT or Patriot stage 2 heads, they helped the flow on my stang alot. and FYI ported NPI heads wont flow as good as PI heads, reason being is no matter what NPI or PI they flow shi**y. Id also go with an aftermarket intake, because you are right about the plastic intake and the PI intake is crappy as well. good luck with your build, and you should also know your PI compression will be higher than your NPI compression.
04-24-2007, 07:25 PM
#4
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RE: To PI or not to PI?
NPI heads ported will flow as well as PI heads. Infact, they will outflow them on the exhaust side a bit. The thing you need to get rid of is that NPI Intake. IT IS JUNK!!!!!! I CANNOT emphasize that enough! With a NPI Intake, you wont have any power above 4500 rpm! Building a motor with a NPI Intake would be like telling a olympicrunner to run the 400m dash with a straw to breathe through
EDIT: Also, if you arent going aftermarket cams, get PI Cams, not NPI. They are good for another 10-15rwhp vs NPI cams.
EDIT: Also, if you arent going aftermarket cams, get PI Cams, not NPI. They are good for another 10-15rwhp vs NPI cams.
04-24-2007, 08:16 PM
#7
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RE: To PI or not to PI?
ORIGINAL: 2002GTAUTOVERT
why would you port NPI heads, and not PORT PI heads.. wouldnt Porting the better flowing heads make them... BETTER???
why would you port NPI heads, and not PORT PI heads.. wouldnt Porting the better flowing heads make them... BETTER???
2002GT - If NPI compression would be lower, wouldn't this be better for FI?
04-24-2007, 08:21 PM
#9
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RE: To PI or not to PI?
im running 10psi with my original pistons... the whole motor is forged, but im sure my compression is up there.. wouldnt run more than 10psi, i know a guy who is running 12 but i dunno how long his motor will last. even though something is free, why use it if its crappy? why not do it right the first time,dont even spend money on porting something that you will eventually want to swap out if you go F/I
04-24-2007, 08:37 PM
#10
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RE: To PI or not to PI?
So the NPI setup wouldn't be worth it for the lower compression? Then again I am getting a forged rotating assembley, so I could always do it with dished pistons.