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Unread 02-13-2008   #1 (permalink)
JCLINTB is offline Apprentice


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Default new to the 4.6L what exactly is PI?

I have been driving 5.0's for as long as I can remember. I hit 190k on my 94 gt and was going to cost more to keep it up than get a new one, my buddy pretty much let me have his 2000 GT vert (well wife did..lol) and now here I am happy but lost in the new modular world. so I read that the 2000 has vast improvements over previous years and puts out a good bit more power I assume that what all this talk about PI is, but what exactly are the differences and do all 2000 GT's have them? are there any issues with these engines to be aware of? thanks for helping a newb out
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Unread 02-13-2008   #2 (permalink)
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Quote:
Originally Posted by JCLINTB View Post
I have been driving 5.0's for as long as I can remember. I hit 190k on my 94 gt and was going to cost more to keep it up than get a new one, my buddy pretty much let me have his 2000 GT vert (well wife did..lol) and now here I am happy but lost in the new modular world. so I read that the 2000 has vast improvements over previous years and puts out a good bit more power I assume that what all this talk about PI is, but what exactly are the differences and do all 2000 GT's have them? are there any issues with these engines to be aware of? thanks for helping a newb out
PI stands for Performance Improved. Basically Ford ported out the heads and put a bigger intake and cams in it. The upgraded the parts to get more air in the engine. All 99-04 GT's have them, as that is one thing that makes them a GT.

Thanks
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Unread 02-14-2008   #3 (permalink)
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actually its Power Improved...no big deal though. one thing to keep in mind though is that the PI heads are cc'd for PI pistons which means that if putting PI heads on a non PI engine will increase your Compression to about 10.5:1 which isnt bad but will limit you on power adders.

The PI heads actually flow less then non PI heads but the configuration of the vavles takes away from some of the shouding affect that was going on with the non-PI heads.

j
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Unread 02-14-2008   #4 (permalink)
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so what you are saying is if i should happen to just port and polish my npi heads i'd have better heads than the pi ones???
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Unread 02-14-2008   #5 (permalink)
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actually the correct terminology in Ford lingo is PI stands for "Police Interceptor" and the improved cylinder heads are know as Horsepower Improved, it was the magazines that changed the name to PI and fugged it all-up, typical of them
 
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Unread 02-14-2008   #6 (permalink)
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Quote:
Originally Posted by RandyStinchcomb View Post
actually the correct terminology in Ford lingo is PI stands for "Police Interceptor" and the improved cylinder heads are know as Horsepower Improved, it was the magazines that changed the name to PI and fugged it all-up, typical of them
I thought that the Police Interceptors where strictly known as CVPI "Crown Victoria Police Interceptor". I know the first car to use the 4.6 was the Towncar, and then Crown Vic. The Police Interceptor wasn't introduced till 1999, so that would make sence that they used the heads on the new 1999 Mustang GTs. The only real big 'engine' difference between Police Interceptors and Crown Vics was the intakes used on the Police Interceptors. So would the heavy duty transmission, heavy duty brakes, a roll bar be considered PI as well?

Another mislead mith about the Modular enigine is that it isn't called modular because it has aluminum, it is called that from a manufacturing plant protocol, "Modular", where the plant and its tooling could be changed out in a matter of hours to manufacture different versions of the engine family.
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Unread 02-15-2008   #7 (permalink)
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straight from the ford site.

4.6L POWER
IMPROVEMENT (PI)
CYLINDER HEADS
M-6049-P46** RH 2V
M-6050-P46** LH 2V
Current production 4.6L SOHC 2V
Romeo engine aluminum cylinder heads
Fully machined and assembled
with production Mustang GT valvetrain
and camshaft
Great for custom engine builds
Less expensive than replacing valvetrain
and remachining a used cylinder head
Less expensive alternative to aftermarket
performance heads
Can be used on 1996-98 engines
with additional modifications and parts
43.9 +/– 1.5 cc combustion chamber
Raises compression on 1996-98
engines to 10:1


j
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Unread 02-15-2008   #8 (permalink)
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So no "PI" as far as our cars go refers to the improvement ford made to increase power in the lacking 96-98 motors.

And for tony's question a ported PI will out do a ported NPI. having a high flow rate does not mean that you will make the most power. there is alot more to making power.


read this...its an awsome article. i have it in my favorites folder.

Cylinder Head Porting Mistakes - Engine Masters Magazine

j
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Unread 02-15-2008   #9 (permalink)
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well I am glad to see I am not the only one confused on the exact meaning of PI, but I think I got it now thanks for the help!!
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00' GT VERT- MAC LT headers, MAC prochamber H Bassani cat-back, MAC CAI, B&M short throw,
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Unread 02-15-2008   #10 (permalink)
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Quote:
Originally Posted by 410cougar View Post
straight from the ford site.

4.6L POWER
IMPROVEMENT (PI)
CYLINDER HEADS
M-6049-P46** RH 2V
M-6050-P46** LH 2V
Current production 4.6L SOHC 2V
Romeo engine aluminum cylinder heads
Fully machined and assembled
with production Mustang GT valvetrain
and camshaft
Great for custom engine builds
Less expensive than replacing valvetrain
and remachining a used cylinder head
Less expensive alternative to aftermarket
performance heads
Can be used on 1996-98 engines
with additional modifications and parts
43.9 +/ 1.5 cc combustion chamber
Raises compression on 1996-98
engines to 10:1


j


thats NOT Ford, that's Frpp and they get **** wrong ALL the time...
these are the same people that tell you the 8th letter in the vin code determins a Windsor or Romeo engine frpp has been full of errors and alot of other BAD info over the years.....
 
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Unread 02-15-2008   #11 (permalink)
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yeah don't believe everything you read in magazines and especially the internet...
thanks for that info cougar
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Unread 02-15-2008   #12 (permalink)
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very true. anyhow we are all on the same page so thats good. Damb acronyms.

j
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Unread 02-15-2008   #13 (permalink)
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Default Frpp

Ford doesn't even accept FRPP as "Ford" parts - the warranties for FRPP parts (and yes, they can be VERY interesting reading, esp. about what happens with new FRPP parts on new Ford cars) all contain a line in which Ford calls FRPP parts "aftermarket" parts, and yes, except for the "interesting" warranty items recently added, they can void a Ford's warranty.

(I won't get into the fun parts, but they are just as misunderstood and quoted as the debate over PI).

I think Randy has it right, there was mass confusion (perhaps even originally sourced with Ford or FRPP, who sometimes get it wrong themselves ABOUT themselves) in the trade pubs and magazines, and it all became legend after that. I tend to remember the most recent thing I've experienced or read when it comes to new terms as they enter my vocabulary, and sure, a single authoritative source can mess up and the whole shebang goes off at a tangent.

I bet we can peruse some Ford dealer sites and find all sorts of versions of the terms in use there, too.



Quote:
Originally Posted by RandyStinchcomb View Post
thats NOT Ford, that's Frpp and they get **** wrong ALL the time...
these are the same people that tell you the 8th letter in the vin code determins a Windsor or Romeo engine frpp has been full of errors and alot of other BAD info over the years.....
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