View Poll Results: Which to do?
Full PI H/C/I swap
5
83.33%
PI intake swap with MHS NPI Stage 2/2.5 cams
1
16.67%
Voters: 6. You may not vote on this poll
NPI Cams and PI intake or full PI swap?
08-24-2011, 06:16 AM
#51
Join Date: Aug 2010
Location: California
Posts: 32
From experience doing all that stuff back when I had my non pi setup, the PI manifold is the BEST bang for the buck. He should pick up atleast 15rwhp/15tq and a better curve just off that. Cams, eh maybe 10 more hp. I would stick with non pi heads, do the PI manifold, and honestly just save the rest of the money. Whats the point in spending $500-$600 on cams, when gains will be minimal and install will be a PITA? Agreed, with the used centri option. I vote, PI manifold, then throttle body/plenum if he doesnt already have it and full exhaust, other than that suspension/tires and save for some sort of p/a. Those non pi cars dont pick up gains worth shi*. Just for numbers sake, I had EVERY bolt on in the book (slp longtube, slp offroad x, slp catback, accufab t/b, accufab plenum, steeda udps, cai, custom tune, etc) and through an auto my car pushed out 202rwhp.....after I did the blower, I later added a PI manifold and picked up 30rwhp/41 tq. Pretty good for $180
08-24-2011, 06:51 AM
#52
3rd Gear Member
Join Date: Jan 2009
Location: Florida
Posts: 570
Some of my observations:
PI cams over NPI cams is about 15-18RWHP
NPI Stage 2 cams figure 25RWHP on top of that if starting with NPI cams
NPI spec cams make about 10 more midrange than a PI swap due to the well advanced intake centerline, PI swap with similar duration cams makes about 10 more HP from the compression bump.
PI intake is worth 15-30RWHP above 4500RPM and especially above 5000 as the NPI nose dives really hard then. At 6000RPM I think its a 30RWHP gain give or take.
Stock injectors will be fine.
Trade the early MAF and air tube for one from a 02-04GT before you get it tuned, they are a good bit better and usually you can get them for near free.
Longtubes make more power gains on NPI heads than PI since the stock NPI exhaust port really really sucks.
MHS Stage 1 blower cams are actually bigger than most others Stage 2 blower cams, plus they are advanced to the best location for a stock valve head (run the intake lobe at 110ICL is a good place to be with a blower).
There is a set of lightly used (read perfect shape) Stage 2 NPI cams degreed and all for sale that I don't expect them to be around long.
PI cams over NPI cams is about 15-18RWHP
NPI Stage 2 cams figure 25RWHP on top of that if starting with NPI cams
NPI spec cams make about 10 more midrange than a PI swap due to the well advanced intake centerline, PI swap with similar duration cams makes about 10 more HP from the compression bump.
PI intake is worth 15-30RWHP above 4500RPM and especially above 5000 as the NPI nose dives really hard then. At 6000RPM I think its a 30RWHP gain give or take.
Stock injectors will be fine.
Trade the early MAF and air tube for one from a 02-04GT before you get it tuned, they are a good bit better and usually you can get them for near free.
Longtubes make more power gains on NPI heads than PI since the stock NPI exhaust port really really sucks.
MHS Stage 1 blower cams are actually bigger than most others Stage 2 blower cams, plus they are advanced to the best location for a stock valve head (run the intake lobe at 110ICL is a good place to be with a blower).
There is a set of lightly used (read perfect shape) Stage 2 NPI cams degreed and all for sale that I don't expect them to be around long.
08-24-2011, 03:18 PM
#56
3rd Gear Member
Join Date: Jan 2009
Location: Florida
Posts: 570
The cam swap must have been way off degree wise.
There is zero gain with a PI intake up to about 4500RPM, rather its a loss. Above 5500RPM the gains grow and grow with RPM as the NPI basically becomes a cork. With a stock cam motor there is no power above 5500 anyway.
08-24-2011, 03:20 PM
#57
3rd Gear Member
Join Date: Jan 2009
Location: Florida
Posts: 570
08-27-2011, 10:22 PM
#59
From experience doing all that stuff back when I had my non pi setup, the PI manifold is the BEST bang for the buck. He should pick up atleast 15rwhp/15tq and a better curve just off that. Cams, eh maybe 10 more hp. I would stick with non pi heads, do the PI manifold, and honestly just save the rest of the money. Whats the point in spending $500-$600 on cams, when gains will be minimal and install will be a PITA? Agreed, with the used centri option. I vote, PI manifold, then throttle body/plenum if he doesnt already have it and full exhaust, other than that suspension/tires and save for some sort of p/a. Those non pi cars dont pick up gains worth shi*. Just for numbers sake, I had EVERY bolt on in the book (slp longtube, slp offroad x, slp catback, accufab t/b, accufab plenum, steeda udps, cai, custom tune, etc) and through an auto my car pushed out 202rwhp.....after I did the blower, I later added a PI manifold and picked up 30rwhp/41 tq. Pretty good for $180
08-28-2011, 06:17 AM
#60
5th Gear Member
Join Date: Dec 2005
Location: NJ
Posts: 3,769
is yours an auto or manual? I was putting that down through an auto, so if you are a manual there ya go...
Also, with the addition of a throttle body, pullies, al driveshaft....dont expect more than 10 - 12 rwhp from ALL of those combined...if you're lucky
Also, with the addition of a throttle body, pullies, al driveshaft....dont expect more than 10 - 12 rwhp from ALL of those combined...if you're lucky
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