i just bought my 1st gt a few weeks ago. its a 96 gt vert. the car is in great shape but that 215hp isnt gonna do it for me. i keep reading different things about "PI" and "NPI" 2v and 4v and frankly im a tad bit confused. i have no idea whats in my car or what route i should be taking to get more power. someone school me real quick
school me on these modular motors
- Thread starter 2wheelryder
- Start date
PI= power improved
NPI= non power improved
Between '96-'98, the Mustang had NPI heads, intake and cams. Starting in '99, they used PI heads, intake, and cams to give the modular 4.6 more horsepower. So a good start for you would be to install all of those parts, or upgrade to Trickflow heads, aftermarket cams, whichever your budget allows for. At the same time, I don't know California's emission laws, so it's anybody's guess what you can and can't install, or what will or won't let you pass.
NPI= non power improved
Between '96-'98, the Mustang had NPI heads, intake and cams. Starting in '99, they used PI heads, intake, and cams to give the modular 4.6 more horsepower. So a good start for you would be to install all of those parts, or upgrade to Trickflow heads, aftermarket cams, whichever your budget allows for. At the same time, I don't know California's emission laws, so it's anybody's guess what you can and can't install, or what will or won't let you pass.
+1
That why New Edge cars (ones that look like mine in my sig) are so much faster than the 96-98 cars. The NPI heads, cams, and intake really hold the 96-98 2V's back even with mods. You need to get rid of those pieces ASAP.
jeremy canter
Member
fast97gt
Active Member
Yo night fire before you go filling this guy up on the edge cars being so much faster the the 96-98 car because of the engines, my car with all bolt-ons and worn out npi would run almost a second quicker then a completely stock new edge. Now to the OP, I went and swapped the old npi motor for the newer pi motor from a crown vic. Yes I feel a definite power increase but not much. However there are claims of npi motors with the pi head set-up produce more powere then a stock pi motor.
trinity_gt
10 Year Member
A bone stock PI 99-04 runs ~14-sec. So you're saying a bolt-on NPI is running 13.0s? What was your rwHP and what were the "bolt ons" mod? Besides the engine, what other mods were made to the car run ETs in that range?
Yeah they are the same but it is a PI motor so it may need a tune after install in your NPI Mustang. Another option is PI cams, PI Intake and a tune. If you know what you are doing you can change the cams without removing the chains. With these simple, cheap mods you will redline at 5K+ and it will have much better mid and top end power. Another "must have" mod is some 3.73 or 4.10 gears since they will let you take advantage of the new engine rpm limits and the 4.6 is not known for having much torque. I went with 3.55's only cuz I do a lot of highway miles so I'm happy with them. It will smog with the stock tune but it will run MUCH better with a custom tune. So when you need to smog it you just put back the stock tune. The smog guys will not be able to tell the difference in intakes and they obviously can"t see the cams. Thats how i roll.....
If you have other questions on these cars PM me and I'll be happy to give you more tips.
If you have other questions on these cars PM me and I'll be happy to give you more tips.Yeah they are the same but it is a PI motor so it may need a tune after install in your NPI Mustang. Another option is PI cams, PI Intake and a tune. If you know what you are doing you can change the cams without removing the chains. With these simple, cheap mods you will redline at 5K+ and it will have much better mid and top end power. Another "must have" mod is some 3.73 or 4.10 gears since they will let you take advantage of the new engine rpm limits and the 4.6 is not known for having much torque. I went with 3.55's only cuz I do a lot of highway miles so I'm happy with them. It will smog with the stock tune but it will run MUCH better with a custom tune. So when you need to smog it you just put back the stock tune. The smog guys will not be able to tell the difference in intakes and they obviously can"t see the cams. Thats how i roll.....
so what you're saying is i wouldnt have to get a PI head i could just use PI cams and a PI intake on my NPI? my car already has a set of 3.55's in it and i wouldnt want to go with a bigger gear for the same reason that you didnt, i do alot of highway driving
Was the new edge car parked?
Like trinity said it is very hard for a stock non ported NPI car with just bolt ons to run 13s. Now with P.I cams and intake that is acheivable, but just bolt ons come on, sounds like your the one filling heads around here.LOL dude you just said that you car has just about every bolt-on possible.....of course you're going to outrun a stock PI car. Fact of the matter is that there's a 45-50HP difference between his NPI GT and PI GT stock for stock. That coupled with the fact that you can find PI parts for dirt cheap makes a PI swap a very attractive mod.
Skidzz
Tinkerbell
My personal advice to you is to just buy the PI intake and go with some aftermarket cams. You could do that for cheaper than going with the entire PI setup. No one has mentioned it yet, but putting the PI heads on a NPI motor will bump the compression up too much to add a supercharger later. The heads themselves are only worth about 10-15 rwhp. The cams and intake are where the real power is.
I did the whole PI swap on mine. I thought "No big deal, I'll be happy on all motor with 260+rwhp." And....I was happy, for about the first 2 years, but now I really want more power. I can get more if I finish up all the bolt-ons. I'd say that with full suspension, good tires, and the rest of the bolt-ons, this car could run mid-low 12' in ideal conditions. However, I can't really do forced induction unless I rebuild the motor with forged internals or atleast rebuild it for low compression, and that's a bummer.
So, I say go with PI intake, maybe some comp cams, and then finish up your exhaust, suspension, etc. and start saving for a blower. You'll be much happier in the end IMO.
I did the whole PI swap on mine. I thought "No big deal, I'll be happy on all motor with 260+rwhp." And....I was happy, for about the first 2 years, but now I really want more power. I can get more if I finish up all the bolt-ons. I'd say that with full suspension, good tires, and the rest of the bolt-ons, this car could run mid-low 12' in ideal conditions. However, I can't really do forced induction unless I rebuild the motor with forged internals or atleast rebuild it for low compression, and that's a bummer.
So, I say go with PI intake, maybe some comp cams, and then finish up your exhaust, suspension, etc. and start saving for a blower. You'll be much happier in the end IMO.
ChillPhatCat
20+ Year Stangneter 
Speaking of Plymouth Prowlers... a friend of mine bought one a few years ago and let me drive it the day it arrived on the transporter. It was pretty meh, fairly quick, but the tap shifter was lackluster. Stang >>> Prowler.Similar threads
