How much??

OFFdutyHERO · 03-15-2006, 08:56 PM

I'm trying to find out how much boost I could throw at a NPI 4.6 and not worry about it goin boom. Most of the kits you see are something in between 6-8 psi, but could I safely run 10psi on the stock internals?

3V2000GT · 03-15-2006, 09:12 PM

I wouldnt go above 9 psi, you would be pushing it with 10

whitethunder46 · 03-15-2006, 09:40 PM

It should be the same as the PI, the only difference is heads/cams/intake. The shortblock should all be same internals/rings/etc. But yea, usually nothing more than 8-9PSI if you like to get on it a lot.

2K1TBGT · 03-15-2006, 10:32 PM

8 is my max...
9's knockin on the door, kinda iffy...
10 you're just askin for it...

OFFdutyHERO · 03-16-2006, 03:51 PM

Quote:

Originally Posted by whitethunder46

It should be the same as the PI, the only difference is heads/cams/intake. The shortblock should all be same internals/rings/etc. But yea, usually nothing more than 8-9PSI if you like to get on it a lot.

No because the PI engines have diff. internals and the heads are very different. PI motors have higher compression than non PI cars because of a smaller combustion chamber made by the different heads.

03-16-2006, 04:20 PM

Just curous, what would the HP gain approx be with 8psi?

Badfish · 03-16-2006, 06:14 PM

Quote:

Originally Posted by Jack The Ripper

Just curous, what would the HP gain approx be with 8psi?

youd be sittin around 360-385 hp

whitethunder46 · 03-16-2006, 06:14 PM

Quote:

Originally Posted by OFFdutyHERO

No because the PI engines have diff. internals and the heads are very different. PI motors have higher compression than non PI cars because of a smaller combustion chamber made by the different heads.

I knew the heads were totally different, but that shouldnt have to much of an effect with how much boost. It mostly is within the internals. But thanks for clarifying that, I learn something new everyday!

03-16-2006, 06:15 PM

Quote:

Originally Posted by Badfish

youd be sittin around 360-385 hp

At the wheels? with 8psi?..... i was figuring about 330...

Badfish · 03-16-2006, 06:15 PM

Quote:

Originally Posted by Jack The Ripper

At the wheels? with 8psi?..... i was figuring about 330...

yep at the wheels

well up here it might be closer to 350

whitethunder46 · 03-16-2006, 06:20 PM

Quote:

Originally Posted by Badfish

youd be sittin around 360-385 hp

No way! From a NON-PI engine!

With a Vortech blower, NON intercooled and on STOCK engine, they're website says it will produce 323HP (in engine). So thats like 300RWHP, but with his full exhaust set up it would prolly be around 335-340RWHP. Change to PI and boom, 390RWHP

OFFdutyHERO · 03-17-2006, 09:08 AM

Quote:

Originally Posted by whitethunder46

No way! From a NON-PI engine!

With a Vortech blower, NON intercooled and on STOCK engine, they're website says it will produce 323HP (in engine). So thats like 300RWHP, but with his full exhaust set up it would prolly be around 335-340RWHP. Change to PI and boom, 390RWHP

Thats where I would run into problems tho. When you swap a NPI motor to PI heads it jacks the compression to 10.5:1 And with that high of compression I would have to lower the boost to somewhere around 6+/- PSI.....its a bummer.

Jon when you said 360-385 you were referring to a PI car right.

RedFirevert04GT · 03-17-2006, 12:56 PM

You can lower the compression jump on a PI swap by porting out the combustion chambers a bit. Make sure this is done very carefully and get the heads cc'd once it's finished to make sure you've got everything correct.

2000novigt · 03-17-2006, 03:41 PM

I run 10psi on stock internals and so far...all good!!

GT4DUMMIES · 03-18-2006, 04:10 PM

actullay u can run 12 or 14 psi - depends on your tune - u maily have to worry about the hp rating not so much the boost - about 400-420 rwhp is all u want with a stock block to be "safe" - however you can pull 525-575 rwhp out of it but - it could blow at any second - or last for years but that the gamble.

03-15-2006, 08:56 PM	#1 (permalink)
OFFdutyHERO what?? Join Date: Aug 2005 Location: Michigan Posts: 305	How much?? I'm trying to find out how much boost I could throw at a NPI 4.6 and not worry about it goin boom. Most of the kits you see are something in between 6-8 psi, but could I safely run 10psi on the stock internals? __________________

03-15-2006, 09:12 PM	#2 (permalink)
3V2000GT 46MONSTER Join Date: Jan 2006 Location: Wheaton, IL Posts: 2,209	I wouldnt go above 9 psi, you would be pushing it with 10 __________________ 2000 GT Black on Tan, TKO 600: 370rwhp 370rwtq NA Built 3v 2004 Honda CBR 600 F4i Black/Red 2000 SVT Lightning Silver i love jinny!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!! lucky is awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

03-15-2006, 09:40 PM	#3 (permalink)
whitethunder46 Always Detailin' Join Date: Oct 2005 Location: Dayton, OH Posts: 3,556	It should be the same as the PI, the only difference is heads/cams/intake. The shortblock should all be same internals/rings/etc. But yea, usually nothing more than 8-9PSI if you like to get on it a lot. __________________ supernissans.net 2001 Mustang GT - Saleen Replica - SOLD 2007 Nissan Sentra 2.0S http://www.cardomain.com/ride/3022272

03-15-2006, 10:32 PM	#4 (permalink)
2K1TBGT Member Join Date: Sep 2005 Location: waller Posts: 80	8 is my max... 9's knockin on the door, kinda iffy... 10 you're just askin for it... __________________ dino/brandon '00L - 13.sl0w '01GT-13.br0ke

03-17-2006, 12:56 PM	#13 (permalink)
RedFirevert04GT Senior Member Join Date: Jan 2006 Location: Va Beach, Va Posts: 336	You can lower the compression jump on a PI swap by porting out the combustion chambers a bit. Make sure this is done very carefully and get the heads cc'd once it's finished to make sure you've got everything correct. __________________ '04 Red Fire vert. KB 1.7L intercooled 9lb with all the trimmin's & Big Boost kit w/ Switch Chip. Mac catted h-pipe & Mac catback. 411RWHP / 414 RWTQ.

03-16-2006, 04:20 PM	#6 (permalink)
Jack The Ripper Posts: n/a	Just curous, what would the HP gain approx be with 8psi?

03-17-2006, 03:41 PM	#14 (permalink)
2000novigt Senior Member Join Date: Feb 2006 Location: Tri-State Area Posts: 241	I run 10psi on stock internals and so far...all good!! __________________ 2000 GT Novi 2000 / 42# Injectors / Anderson Power Pipe / Vortech Mini Race Bypass Valve / Cobra Duel Fuel Pumps & Tank / Flowtech LT's / Flowtech O/R X-pipe / Flowmaster American Thunder Cat-back / BBK 75mm Throttle Body / SCT BA2400 / TFS Upper Plenum / 4.10 FRPP Gears / SCT Tuner / Autometer Boost, Fuel Pressure and Trans. Temp Gauges / Steeda Subframe Connectors / Chrome FR500's / BFG 315-35-17 Drag Radials / Built & Tuned By Kevin @Wicked Motorsports

03-18-2006, 04:10 PM	#15 (permalink)
GT4DUMMIES Senior Member Join Date: Feb 2006 Posts: 107	actullay u can run 12 or 14 psi - depends on your tune - u maily have to worry about the hp rating not so much the boost - about 400-420 rwhp is all u want with a stock block to be "safe" - however you can pull 525-575 rwhp out of it but - it could blow at any second - or last for years but that the gamble.

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