pi heads on 98 gt
09-21-2006, 11:11 AM
#11
Underboss
Join Date: Jan 2006
Location: Helaware
Posts: 20,273
RE: pi heads on 98 gt
Did the PI swap and saw an increase from 185 RWHP to 245 RWHP. Added an Accufab 75mm TB/Plenum and saw an increase of 10 more!! PI swap should be done with the engine out of the car for the purpose of dirt control and not fighting to do the job.
09-21-2006, 01:09 PM
#12
5th Gear Member
Join Date: Apr 2006
Posts: 3,625
RE: pi heads on 98 gt
[quote]ORIGINAL: II 98 GT II
[sm=lame.gif]
WOW ummm, because you've been doing all of this research, you know EVERYTHING??
UMMMM YEAH KINDA LIKE YOU!!!!!!
ORIGINAL: 97targa
Uhhggg I hate when prople think they know everything! Trust me I've been doing a lot of research as I own a 97GT.
Uhhggg I hate when prople think they know everything! Trust me I've been doing a lot of research as I own a 97GT.
WOW ummm, because you've been doing all of this research, you know EVERYTHING??
UMMMM YEAH KINDA LIKE YOU!!!!!!
09-21-2006, 01:19 PM
#13
3rd Gear Member
Join Date: Jul 2005
Location:
Posts: 509
RE: pi heads on 98 gt
I can't open that article but would love to read it [&o]
Thank U all for the info.
Well, what I have heard about the 98 is that it was the last year they used those heads. after that ford made some changes. [:-]
lf the heads were that bad then changing just heads would bring on major power. I doubt that Ford would have used such a restricitve head.
Chances are the entire intake path was opened up and improved.
Regardless, as a matter of logic I would also do the intake manifold.
The 4.6 is OHC design so it would make sense to do cams also.
****!!! I need mo money
Thank U all for the info.
Well, what I have heard about the 98 is that it was the last year they used those heads. after that ford made some changes. [:-]
lf the heads were that bad then changing just heads would bring on major power. I doubt that Ford would have used such a restricitve head.
Chances are the entire intake path was opened up and improved.
Regardless, as a matter of logic I would also do the intake manifold.
The 4.6 is OHC design so it would make sense to do cams also.
****!!! I need mo money
09-21-2006, 03:27 PM
#14
4th Gear Member
Join Date: Jul 2006
Location: Michigan
Posts: 1,125
RE: pi heads on 98 gt
Hmm well sorry that the link didn't work for you. Looks like i've been spam censored or something...
Here it is:
Alot of people have gotten on the bandwagon by thinking you need PI heads with the PI cams and PI intake. You don't and there are some running 12.3's on NA NPI headed motors.
For the owners of the 1996 – 1998 Ford 4.6L 2V Mustang GT, the PI (Power Improvement) swap can provide an excellent power boost for these underpowered motors. The PI swap may consist of a complete head and intake swap for full power benefits or just a PI cam and intake swap for decent power gains and other considerations. The pros and cons of both are discussed below.
Note: 1996 – 1998 Mustang GT’s are non power improved (nPI) equipped cars. 1999 – 2004 Mustang GT’s are power improvement (PI) equipped cars.
The PI cam and intake swap also provides decent power gains absent the draw backs associated with the PI head and intake swap. Swapping PI cams and a PI intake on nPI Stangs results in a 30 – 35 RWHP gain. The cams alone result in a 13 – 16 RWHP gain and the intake results in a 15 -18 RWHP gain. The extra 10-15 on the PI head is the bump in compression with an added cost for the heads.
The benefits of this swap are lower costs, less labor, and the fact that you maintain stock compression ratios. PI cams can be purchased used from many parts forums (such as those found on Corral, Modular Depot, or Mustang World) for about $100. PI intakes can be purchased for $100 - $200 depending on condition and whether or not they have the aluminum cross-over (recommended). The install kit with all the gaskets, heater tube etc, is about another $50 - $60. Therefore, for about $300 or less you can obtain up to an extra 35 RWHP making this mod an excellent dollar for horsepower gain! In addition you can use the saved money to port the NPI heads that will have more hp than if you went the PI head route. Some of the common rebuttles is "well i will prot the PI heads then". However, the drawback is that you have introduced much more airflow that the Pi cams, which are oem btw, can't be used to their full potential resulting in no real gain, but possibly a loss of hp. Too much airflow for the cam setup isn't going to yield hp.
When swapping PI cams, I recommend that you purchase 2001 + cams. These cams are Romeo cams (manufactured in the Romeo plant) and they have bolt on sprockets. Since the sprockets can be unbolted, you can use the Anderson tool to swap the cams. This makes the job a snap since all you have to do is take off the valve covers, cam covers, use the tool to hold the timing chain in place and then swap cams. Conversely, to do the entire PI head swap, you will have to either pull the entire motor, or tear it down in place to remove the heads.
The PI intake is a considerable improvement over the nPI intake. With its increased port volume and improved runner design, this intake has been shown to give up to 18 RWHP increases to the nPI equipped Stang.
When swapping the PI intake on nPI heads, make sure you purchase nPI gaskets since these gaskets seal the water ports. Failure to seal the water ports can result in coolant leaking into the combustion chamber and subsequent engine failure, so be sure to use nPI gaskets. Although these gaskets effectively seal the water ports (a must), they do not completely seal the intake ports. You must use high temp silicone sealant (permatex) to seal these ports. AGAIN… only apply the permatex to the intake. Applying excessive amounts of sealant can cause it to ooze into the intake port and obstruct it resulting in hesitation and reduced power.
I hope this helps any future 96-98 GT owners that you do not need a PI head to make power with these cars. Johnny Langton pioneered the first PI cam and intake swap and his 4.6 2v NPI motor runs 12.3 so he is proof this can be done and on a budget.
Here it is:
Alot of people have gotten on the bandwagon by thinking you need PI heads with the PI cams and PI intake. You don't and there are some running 12.3's on NA NPI headed motors.
For the owners of the 1996 – 1998 Ford 4.6L 2V Mustang GT, the PI (Power Improvement) swap can provide an excellent power boost for these underpowered motors. The PI swap may consist of a complete head and intake swap for full power benefits or just a PI cam and intake swap for decent power gains and other considerations. The pros and cons of both are discussed below.
Note: 1996 – 1998 Mustang GT’s are non power improved (nPI) equipped cars. 1999 – 2004 Mustang GT’s are power improvement (PI) equipped cars.
The PI cam and intake swap also provides decent power gains absent the draw backs associated with the PI head and intake swap. Swapping PI cams and a PI intake on nPI Stangs results in a 30 – 35 RWHP gain. The cams alone result in a 13 – 16 RWHP gain and the intake results in a 15 -18 RWHP gain. The extra 10-15 on the PI head is the bump in compression with an added cost for the heads.
The benefits of this swap are lower costs, less labor, and the fact that you maintain stock compression ratios. PI cams can be purchased used from many parts forums (such as those found on Corral, Modular Depot, or Mustang World) for about $100. PI intakes can be purchased for $100 - $200 depending on condition and whether or not they have the aluminum cross-over (recommended). The install kit with all the gaskets, heater tube etc, is about another $50 - $60. Therefore, for about $300 or less you can obtain up to an extra 35 RWHP making this mod an excellent dollar for horsepower gain! In addition you can use the saved money to port the NPI heads that will have more hp than if you went the PI head route. Some of the common rebuttles is "well i will prot the PI heads then". However, the drawback is that you have introduced much more airflow that the Pi cams, which are oem btw, can't be used to their full potential resulting in no real gain, but possibly a loss of hp. Too much airflow for the cam setup isn't going to yield hp.
When swapping PI cams, I recommend that you purchase 2001 + cams. These cams are Romeo cams (manufactured in the Romeo plant) and they have bolt on sprockets. Since the sprockets can be unbolted, you can use the Anderson tool to swap the cams. This makes the job a snap since all you have to do is take off the valve covers, cam covers, use the tool to hold the timing chain in place and then swap cams. Conversely, to do the entire PI head swap, you will have to either pull the entire motor, or tear it down in place to remove the heads.
The PI intake is a considerable improvement over the nPI intake. With its increased port volume and improved runner design, this intake has been shown to give up to 18 RWHP increases to the nPI equipped Stang.
When swapping the PI intake on nPI heads, make sure you purchase nPI gaskets since these gaskets seal the water ports. Failure to seal the water ports can result in coolant leaking into the combustion chamber and subsequent engine failure, so be sure to use nPI gaskets. Although these gaskets effectively seal the water ports (a must), they do not completely seal the intake ports. You must use high temp silicone sealant (permatex) to seal these ports. AGAIN… only apply the permatex to the intake. Applying excessive amounts of sealant can cause it to ooze into the intake port and obstruct it resulting in hesitation and reduced power.
I hope this helps any future 96-98 GT owners that you do not need a PI head to make power with these cars. Johnny Langton pioneered the first PI cam and intake swap and his 4.6 2v NPI motor runs 12.3 so he is proof this can be done and on a budget.
09-21-2006, 03:39 PM
#15
4th Gear Member
Join Date: Jul 2006
Location: Michigan
Posts: 1,125
RE: pi heads on 98 gt
ORIGINAL: 97targa
UMMMM YEAH KINDA LIKE YOU!!!!!!
UMMMM YEAH KINDA LIKE YOU!!!!!!
OH yea, when you say stuff like this:
ORIGINAL: 97targa
Uhhggg I hate when prople think they know everything! Trust me I've been doing a lot of research as I own a 97GT.
Uhhggg I hate when prople think they know everything! Trust me I've been doing a lot of research as I own a 97GT.
09-21-2006, 04:11 PM
#17
5th Gear Member
Join Date: Apr 2005
Location: South Jersey
Posts: 2,489
RE: pi heads on 98 gt
ORIGINAL: 97targa
First off. You cannot just change the intake and cams and get those kind of numbers!!!!! You can change the cams but will only get like 8-10hp not even 5-6 rwhp. The big change is in the intake and intake runners of the head. They just outflow the 96-98 heads substantially. You cannot put a pi intake on a non-pi head and expect big gains if the stock head CANNOT MOVE THAT MUCH AIRFLOW IN THE FIRST PLACE!!!!! That's why they changed the heads! Uhhggg I hate when prople think they know everything! Trust me I've been doing a lot of research as I own a 97GT. You need to do the complete swap. new heads will run you $700 plus shipping. You can get head changing kits for around $150 shipped! If you plan on nitrous or any supercharger you need to get ARP bolts. The 96-98 GT's with PI heads make 10:1 compression and the stock type bolts won't beable to handle boost as well as newer engines with the stock 9:38 compression ratio. You can have the tech guys grind off the "quench pad" which is merely a bump that sits next to the intake valve to induce fuel mixture, it adds compression. But if it were me I wouldn't have anyone touching my heads like that. Labor will be from $1000-1200. If you have anyone quote you a price of $750 like this guy says,I would be aware, because these heas need to be timed perfectly and takes atleast an hour to do so and you need to know what the hell you are doing!
ORIGINAL: droptoppony
Most of the power from a PI swap comes from the PI Intake and PI cams. You can gain 30-35rwhp from that swap or about 40-45rwhp from the complete swap.
Labor will run you 750-1000
ORIGINAL: Poobs
Guys
How much should a PI swap cost including labor ?
I agree that heads are the key to power in the stang motor
Guys
How much should a PI swap cost including labor ?
I agree that heads are the key to power in the stang motor
Labor will run you 750-1000
And yes you can just change the cams/heads and get those numbers because many have done it and have posted dyno sheets to prove it...NOOB...The stock NPI heads are not the cork the intake is so when you remove the NPI intake the NPI heads flow pretty well. When you put PI valves in a NPI head they are fairly close in flow #'s NOOB but you wouldn't know this stuff because you just "research" and don't do...NOOB!
09-21-2006, 04:13 PM
#18
Join Date: Jan 2006
Posts: 40
RE: pi heads on 98 gt
PI swap would put you a little over the stock hp of a new edge. It is a good mod outside of FI.
Edit: The intake produces the most gains, the heads would be useless without swapping the intake. Also I have heard that you can just swap the intake and keep the npi heads, and I have also heard that you cannot............
Edit: The intake produces the most gains, the heads would be useless without swapping the intake. Also I have heard that you can just swap the intake and keep the npi heads, and I have also heard that you cannot............
09-21-2006, 04:23 PM
#19
4th Gear Member
Join Date: Jul 2006
Location: Michigan
Posts: 1,125
RE: pi heads on 98 gt
You can put a PI intake on NPI heads. Either you have to do the job yourself with high-temp gasket maker or you can buy a kit from a number of different places. Livernois is one example.
