4.6L (1996-2004 Modular) MustangTechnical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within. Sponsored by Cruizin Concepts
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Alright so it seems that people might still be debating whether or not a PI intake manifold can be attached to NPI heads. Well here is a how to put on the PI manifold onto the NPI heads. This swap works and there is not a whole lot to do to get it to work. This how to is how I did the swap. Some people may want to do it differently or will make you do different things. Read up do your homework and decide what is best for you. This process worked for me and it has given my car a little more power at high rpm's and at higher speeds. I noticed a better pull when going to pass people, so from about 70 mph and faster, but i did not notice a change from a 0- 60 standpoint. Well here it goes, got pics, not sure on the torque specs cuz i dont have them readily available, but you should get the point.
First off you will need to get the necessary parts. Some parts can be jerry rigged if you wish or you can do it the right way. These are the parts thatI bought.
Mind you most of these parts are for a 2001 Mustang GT. I just went to the parts counter at the dealer and said i needed this and this for a 2001 GT. You can do the same. There are PIintake manifoldgaskets, a PI water coolant tube, PI water pump nipple, 180 degree thermostat, thermostat gasket, EGR gasket, Coolant hose from heater core to intake manifold(cuz i had to cut mine), 16 new O-Rings for the fuel injectors, and High Temp RTV sealant. I forgot to buy a waterpump o-ring and it leaked after i re-installed it, so i recommend getting one of those also. The next thing you will also be needing is a PI intake manifold.
Here you can obviously see the difference between the PI manifold on the left and the NPI manifold on the right hand side. The PI manifold has much longer and larger runners and is one of the reasons you need different parts of the PI mustangs to make it work.
Ok so now for the actual work. Disconnect your battery and apply your parking brake(if manual). You will have to drain the coolant out of your engine so that when you pull all the hoses and manifold you wont get coolant everywhere and cause a big mess. So save yourself the hassle and drain the coolant. The next thing would be to pull the strut tower brace if equipped. There are 8 bolts and then it slides right off. The next step is to disconnect the MAF and intake temp sensors and pull off the intake tubing to the throttle body.
Next step would be to pull off the alternator, alternator bracket, upper coolant hose, the plastic tubes coming from the PCV valves, and drive belt. I also disconnected all of my spark plug wires so that they would be out of the of everything, might want to number em if you feel you won't remember where they go. If you have an aluminum crossover on your NPI intake manifold already you will not need to buy this part. If you are converting over from the original all plastic NPI intake manifold you may need to pick one of these up, but you can get away without it. I already have the aluminum crossover so I did not need to find one.
Now this is also where people may differ on how to remove the intake manifold and the components on it. (For your information, I didnt take pictures of taking it all apart, just putting it back together, so the PI manifold is already on it, but its the same procedure putting it on as it is taking it off, so dont nag on me tellin me that i already have a PI intake on it ) I decided to disconnect all the wiring, vacuum lines, EGR valve, and throttle cables running to the throttle and upper plenum, then loosened the 5 or 6 bolts holding it on. You will need to take this off and swap it onto the new manifold so might as well do it now. If a bolt is stuck you will have a heck of a time trying to hold onto it while its spinning on your work bench. I also pulled off at this time a sensor of somesort that has two vacuum lines running into it on the drivers side of the intake manifold. Comes off with two bolts.
the next step would be to take off the fuel rails and injectors. First I took all the connectors off the injectors and the rest of the sensors that were still connected. I didnt really feel like disconnecting the fuel lines from the rails, so i took off the bolts holding down the rails and layed the fuel rails with injectors off to one side out of the way for now. Be careful here again because the rails still have pressure in them, release this pressure by depressing the valve(it lookes like a valve stem) on the fuel rail, it will spray some fuel so cover it with a rag, and then you should be safe.
There are now only11 bolts keeping you away from taking off that manifold. Make sure not to bust any of these off in the head. There are two holding down the thermostat housing, make sure to take both out as they are also holding down the intake manifold.
Now it is time to remove the water pump. Take off the bolts holding it and and pull it straight out, it might stick a little because it is held in place by an o-ring rather than gasket, so dont go overboard and wreck your water pump. Then you will need to disconnect the coolant hose running along the v of the block. There is a 13mm bolt and a 10mm bolt holding it on, they are on the back side of the drivers side head. Take your time and get a good grip on them, you do not want to round these off, they are kind of difficult but like i said, take your time. You will then need to take out the nipple from where the back of the water pump is. Now i've heard of people already having the correct nipple on their car, so it might not apply to you, I will show you a picture of the one you NEED to use if you buy the new coolant hose. It doesn't use a rubber hose to connect to it, it is all metal and needs to seal with the o-rings of the new nipple. This will take a little bit to get out, it is press fit in and will take some blows from a rubber mallet, you may need to resort to a plastic or metal hammer but be careful here also, you don't want this thing stuck in that hole, it will then be a pain the ****.
You can then slide the new water pump nipple into where the old one was, you might need to get the handle side of a screwdriver to pursuade it into place. Once that is on you can install the new coolant pipe and bolt it onto the back of the head. It only uses the one bolt to hold it on, so i suggest you put the other one away someplace so at the end of assembly you dont get worried when you have an extra bolt in your hands.
Now go ahead and clean up your waterpump and put a new o-ring on it. Put the water pump back on your engine. And now comes the fun part. Putting your PI intake
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