what will it run?

[justinschmidt1]

how do you guys race your NPI cars? i always ran it to redline to shift... i knew it fell on its face up top, but i never really had the experience to start experiementing with shifting sooner...

Bolt on NPI youd prolly want to shift at 5500 or so.

PI intake prolly extends it closer to 6k

WIth pi intake and bolt ons i was going to 6k

 

[MustangChris]

o i c. yea, thats about where i'd shift. 5700 or so. right before redline.

 

[Musturd]

Yea 55-58 was best with my npi car when shifting at 62 it would go like 1-2 tents slower and shoot flames out the pipes Cus of the fuel shut off

 

[MustangChris]

geeze. just thinking about it makes me not even miss the slowness of a NPI.... but it certainly makes me miss the smell of the traction compound and the burning rubber :-(

 

[Musturd]

Yea exactly NPI is good for a daily driver and decent on gas that's about it.

 

[MustangChris]

yeah. i got good MPG in mine. my uncles crown vic did too.

 

[D3VST8R96GT]

i used to get decent mileage in my NPI ....not so much after the PI motor swap lol maybe its just the foot wanting to stay above 2500rpm

 

[ogre]

how do you guys race your NPI cars? i always ran it to redline to shift... i knew it fell on its face up top, but i never really had the experience to start experiementing with shifting sooner...

i actually have an old dyno of a PI intake/cam swapped turd, it clearly showed that it fell off WAY before redline. i think i lost it when my old computer died.

as far as fuel goes, my 3.27 reared crown vic gets 21. i get 17 out of my headswapped 98, on my way from pindy i got a whole 19mpg rolling 70-75 on the highway with 4.10's. I had a 01 grand marquis that would get 25 consistantly with 2.73 rear.

 

[justinschmidt1]

i actually have an old dyno of a PI intake/cam swapped turd, it clearly showed that it fell off WAY before redline. i think i lost it when my old computer died.

as far as fuel goes, my 3.27 reared crown vic gets 21. i get 17 out of my headswapped 98, on my way from pindy i got a whole 19mpg rolling 70-75 on the highway with 4.10's. I had a 01 grand marquis that would get 25 consistantly with 2.73 rear.

yea, they usually peak 5k, maybe a little over 5k.....but they dont fall off completely.

Either way, you want to shift like 500 rpms above peak usually which would be 5500-5800 rpms usually.

With an auto its better to rev higher just so the RPMS dont drop down too much which is why I was shifting more like 5800-6k in my auto.


This is why its best to go to the track and test things...but I can almost guarantee you that your best times will come when shifting around 5800 rpms.

 

[sneaky98gt]

high 12s?? ? ? ? ?? lol. lets stop e-racing... right now. lol.

While most folks can't do it, it is certainly possible. I have seen video of a PI head swap, bolt on, geared, 5-speed 98 GT go 13.1 on street tires. 17x9s all the way around, and full weight. Also have a good friend that has run 12.5 in a PI motor car with bolt ons and a set of Hitech cams, on the stock clutch and not leaving very hard on it.

i used to get decent mileage in my NPI ....not so much after the PI motor swap lol maybe its just the foot wanting to stay above 2500rpm

I recently swapped a PI motor in my car, and I have definitely had a drop in gas mileage over the old NPI motor. With the NPI motor, I got 25-27 regularly; after the cams, I only got 2 good tanks of gas through it, but got 24 and 25 on those; now with the PI motor, I've had a best of 23, but it's usually been around 21-22 mpg.

yea, they usually peak 5k, maybe a little over 5k.....but they dont fall off completely.

Either way, you want to shift like 500 rpms above peak usually which would be 5500-5800 rpms usually.

With an auto its better to rev higher just so the RPMS dont drop down too much which is why I was shifting more like 5800-6k in my auto.


This is why its best to go to the track and test things...but I can almost guarantee you that your best times will come when shifting around 5800 rpms.

If someone has a dyno sheet of their car, then you can just do the gear multiplications and see where they cross for each gear to see EXACTLY where the optimal shift point is. I actually have a program in Excel that will do all of this for you if you input the dyno numbers and gear numbers.

For example, here's what the torque on the wheels looks like for completely stock '02 GT (5 speed) looks like shifting at 5800 rpm.



Notice that the torque just starts to fall off before the 1-2 and 2-3 shifts, which means that 5800 should be just right. It rises back up a significant amount on the 3-4 shift, which means that 5800 is actually a tick too much, 5700 would probably be about right.

And in that case, I can't imagine an NPI headed car EVER being needed to shift above 5700-5900. With mostly stock parts, I'd say 5700 is a good number to start with at the track, and adjust from there.

 

[justinschmidt1]

While most folks can't do it, it is certainly possible. I have seen video of a PI head swap, bolt on, geared, 5-speed 98 GT go 13.1 on street tires. 17x9s all the way around, and full weight. Also have a good friend that has run 12.5 in a PI motor car with bolt ons and a set of Hitech cams, on the stock clutch and not leaving very hard on it.



I recently swapped a PI motor in my car, and I have definitely had a drop in gas mileage over the old NPI motor. With the NPI motor, I got 25-27 regularly; after the cams, I only got 2 good tanks of gas through it, but got 24 and 25 on those; now with the PI motor, I've had a best of 23, but it's usually been around 21-22 mpg.



If someone has a dyno sheet of their car, then you can just do the gear multiplications and see where they cross for each gear to see EXACTLY where the optimal shift point is. I actually have a program in Excel that will do all of this for you if you input the dyno numbers and gear numbers.

For example, here's what the torque on the wheels looks like for completely stock '02 GT (5 speed) looks like shifting at 5800 rpm.



Notice that the torque just starts to fall off before the 1-2 and 2-3 shifts, which means that 5800 should be just right. It rises back up a significant amount on the 3-4 shift, which means that 5800 is actually a tick too much, 5700 would probably be about right.

And in that case, I can't imagine an NPI headed car EVER being needed to shift above 5700-5900. With mostly stock parts, I'd say 5700 is a good number to start with at the track, and adjust from there.

Thats a sweet program. Could you send me that? lol

But your right, that is how you should really calculate your shift points.

Although I would imagine every car would be slightly different depending on mods.

 

[2v_takeover]

Question: I have my 96gt NPI. Really want to do the PI cam/intake swap and I'm wondering if this will somewhat help that drop off at 5k rpms? I don't really enjoy driving my car only to have her exhausted once it reaches a measly 5000rpm is all. Maybe I'm just to used to my JDM hah.

 

[justinschmidt1]

Yes. The pi parts will extend the power band to at least 5500-6k
Sent from my DROID RAZR using Tapatalk

 

[98Warhorse]

Sounds like i need some drag radials and some driving lessons, I ran a 14.8 with a K&N and a UPR X-pipe, at the time i had the original 2.73 gears. I've got some more work done to the car now and am really anxious to see what it can do under the right conditions. From the looks of the track times on this post it seems like the car is exactly where i want it to be, at this point its all on me to get it there.

Good luck on your run MoonlightGT, it sounds like you'll be able to give your buddy a run for his money.

 

[MoonlightGT]

never made it to the track lol, I dug up this thread from a couple years ago. the SVE mongoose clutch I installed turned out to be garbage so I swapped it out for a ford racing HD. then I was having rear end issues so I had to rebuild that as well. so now I WILL be going this spring. im still hoping for a 13 second slip so we will see what happens.

 

[duff daddy]

Lol