Porting NPI heads
06-10-2009, 11:25 AM
#1
Thread Starter
Join Date: Jun 2009
Location: Texas
Posts: 2
Porting NPI heads
Has anyone here ported there NPI heads? I am looking at doing a PI swap, but was also think about porting some NPI heads. Does anyone have any experience with ported NPI heads please chime in.
06-11-2009, 10:18 AM
#3
5th Gear Member
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
Porting the 4.6 heads SHOULD NOT BE DONE BY YOU.
Best advice, is to buy a set of used PI Heads and intake($400) and have them ported PROFESSIONALLY.
That will bring you to 300HP, and 315 Lbs Torque after tuning.
Unlike the 5.0 , the 4.6 will NOT RUN PROPERLY with uneven ports that are NOT PRECISE, and a tune will be needed either way you go for better performance.Hand porting a Computer Controlled 4.6 is highly unrecommended.
Best advice, is to buy a set of used PI Heads and intake($400) and have them ported PROFESSIONALLY.
That will bring you to 300HP, and 315 Lbs Torque after tuning.
Unlike the 5.0 , the 4.6 will NOT RUN PROPERLY with uneven ports that are NOT PRECISE, and a tune will be needed either way you go for better performance.Hand porting a Computer Controlled 4.6 is highly unrecommended.
06-11-2009, 12:02 PM
#4
3rd Gear Member
Join Date: Aug 2008
Location: Oklahoma
Posts: 912
doing it yourself is a bad idea. However I well ported NPI head will flow just as well as a ported PI.
06-11-2009, 12:13 PM
#5
6th Gear Member
Join Date: May 2007
Location: Columbia, MO
Posts: 6,347
Porting the 4.6 heads SHOULD NOT BE DONE BY YOU.
Best advice, is to buy a set of used PI Heads and intake($400) and have them ported PROFESSIONALLY.
That will bring you to 300HP, and 315 Lbs Torque after tuning.
Unlike the 5.0 , the 4.6 will NOT RUN PROPERLY with uneven ports that are NOT PRECISE, and a tune will be needed either way you go for better performance.Hand porting a Computer Controlled 4.6 is highly unrecommended.
Best advice, is to buy a set of used PI Heads and intake($400) and have them ported PROFESSIONALLY.
That will bring you to 300HP, and 315 Lbs Torque after tuning.
Unlike the 5.0 , the 4.6 will NOT RUN PROPERLY with uneven ports that are NOT PRECISE, and a tune will be needed either way you go for better performance.Hand porting a Computer Controlled 4.6 is highly unrecommended.
i don't know if i should believe this guy. i believe he is the same guy that was infamous in the 5.0 section for drilling into his crank because his flywheel didn't line up.....
06-11-2009, 12:43 PM
#6
3rd Gear Member
Join Date: Aug 2008
Location: Oklahoma
Posts: 912
Porting the 4.6 heads SHOULD NOT BE DONE BY YOU.
Best advice, is to buy a set of used PI Heads and intake($400) and have them ported PROFESSIONALLY.
That will bring you to 300HP, and 315 Lbs Torque after tuning.
Unlike the 5.0 , the 4.6 will NOT RUN PROPERLY with uneven ports that are NOT PRECISE, and a tune will be needed either way you go for better performance.Hand porting a Computer Controlled 4.6 is highly unrecommended.
Best advice, is to buy a set of used PI Heads and intake($400) and have them ported PROFESSIONALLY.
That will bring you to 300HP, and 315 Lbs Torque after tuning.
Unlike the 5.0 , the 4.6 will NOT RUN PROPERLY with uneven ports that are NOT PRECISE, and a tune will be needed either way you go for better performance.Hand porting a Computer Controlled 4.6 is highly unrecommended.
You are correct each port needs to be as close to 100% the same just like the intake manifold does. The stock computer (with a tune or not) in both the fox bodies and later cars does not have a way to control fuel based on individual cylinders. So if one cylinder gets more or less air mass the computer never knows about it.
On our cars the computer assumes that everything past the MAF is the same. Doesn't matter if its a 5.0 push rod motor or a newer modular motor.
06-11-2009, 01:20 PM
#7
5th Gear Member
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
the bump in compression and porting will make a tremendous difference, compared to what you have now.
An aggressive 93 octane dyno tune will be nice, with the bump in compression, your going to have to stay 93 octane, the 4.6 is a ping master
/
An aggressive 93 octane dyno tune will be nice, with the bump in compression, your going to have to stay 93 octane, the 4.6 is a ping master
/
06-11-2009, 01:27 PM
#8
5th Gear Member
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
yea both are the true, but realize back then I was a teenager and that was my very first motor job.
Last edited by aode08; 06-11-2009 at 01:32 PM.
06-11-2009, 01:55 PM
#10
3rd Gear Member
Join Date: Aug 2008
Location: Oklahoma
Posts: 912