[Unfettered Might]

Hello everyone. I have a red 96 XR7 with 140,000 miles and I absolutely love this car. I am by far no newb to turning a wrench, however this is my first 4.6L.

My factory intake has 3 external and 1 internal coolant leak, it goes through a gallon of water a day and since I have to replace the intake anyway, I figured why not do an upgrade.

I apologize in advance if I overlooked a tech article on this, I did do a site search and though I have determined it's a pretty easy swap, I still have a few loose ends in my research that need to be cleared up.

1) It was stated that its a direct swap with two extra steps. What are those extra steps?

2) What are the pros and cons of this swap? Should I just stick with the stock intake?

3) Are all the other parts (sensors, plenum, etc) usable, or do I need to replace them as well?

Thanks for your assistance.

 

[theterminator93]

1) You need to RTV the coolant port to match the PI gasket and use the PI valley coolant tube.
2) About 12 HP gain up near 4000 RPM, but you lose a little torque down low (easily offset with PI cams).
3) Everything else is re-usable.

http://www.modularheadshop.com/Articles/PI intake swap.htm

 

[General Zod]

you need to RTV the coolant port ON THE HEAD is what Brandon was trying to mention in #1

you will probably have to drill and tap the flat boss on the PI intake next to the Tstat to accept your second coolant temp sensor.

 

[1996Project-bird]

FWIW, I just moved the second temp sensor to the heater hose that runs under the valley. Put the gray on the manifold, and move the green. 3/8 NPT tee fitting if IIRC.

 

[Unfettered Might]

Ok I got it. Of course looking for a new heater tube(as opposed to a junk yard) I ran into the coolant mod, so now that's on the list.

I also came across this, pricey but I'm not a big fan of the plastic intake and if I can do this only once....

http://www.latemodelrestoration.com/item/PP-54061/99-04-Mustang-Typhoon-Intake-Manifold-Satin

Anyone have any knowledge on this one? I understand the PI intake sacrifices some low end torque, but is this one an even higher flowing intake than the stock PI or is it the same spec?

I'll either tap the manifold or find a T fitting and run both off the same port, I want to keep good access to the sensor.

 

[theterminator93]

Keep in mind cast aluminum intakes will suffer from heat soak more than the OEM PI intakes will.

 

[Unfettered Might]

Keep in mind cast aluminum intakes will suffer from heat soak more than the OEM PI intakes will.

Yeah that did occur to me after posting. What kind of reliability can I expect out of the revised plastic ones? I had heard they are still prone to cracking.

 

[theterminator93]

The plastic intakes with the aluminum crossover can fail, but the failures I've seen (posted here) in the last 4 years have been few enough to count on one hand. Usually it's the seals between the aluminum and the plastic where it contacts the head. You can avoid this by avoiding used intakes and by changing your coolant regularly.

 

[Unfettered Might]

The plastic intakes with the aluminum crossover can fail, but the failures I've seen (posted here) in the last 4 years have been few enough to count on one hand. Usually it's the seals between the aluminum and the plastic where it contacts the head. You can avoid this by avoiding used intakes and by changing your coolant regularly.

Ok, I've got what I need to know, thanks again for the help guys.

 

[General Zod]

You can also remove the aluminum crossover to clean up any crud and RTV it back together.

 

[XR7-4.6]

The plastic intakes with the aluminum crossover can fail, but the failures I've seen (posted here) in the last 4 years have been few enough to count on one hand. Usually it's the seals between the aluminum and the plastic where it contacts the head. You can avoid this by avoiding used intakes and by changing your coolant regularly.

I've only seen that on cars with dirty orange coolant. Those cars also tend to have the aluminum on the head flange by the coolant port SEVERELY pitted.

 

[theterminator93]

Exactly - hence my comment about making sure you change the coolant regularly.

 

[MadMikeyL]

I have to say, I have actually seen more failures on the aluminum crossover intakes than the all plastic ones. That is probably due mostly to more of them being on the road, but the reason for the failure is exactly the same as why the all plastic ones failed. The plastic becomes hard and brittle from the heat of the engine and the coolant running through it, and eventually it will crack. Dirty old coolant certainly can't help the problem, but I have seen the same failure on well maintained cars with clean coolant, so I consider it to be just the normal lifespan of the intake manifold. If you buy a new intake with the aluminum crossover, figure that it will last 8-10 years, which for the price of an intake manifold and the time it takes to change it, is really not bad, and unless you know you will be keeping the car for more than the next 10 years, probably not worth spending twice as much. That being said, if you did want a permanent solution that you will never have to mess with again, the Typhoon intake might be a good solution, but I would want to hear from other people who have installed them first to verify the build quality. Professional products basically makes cheap chinese knock-offs of other brand-name products, and I know with the typhoon intake that I put on my 393 stroker, the performance was great but it took some time fitting it to the car due to some of the bolt holes not being in exactly the right places, and having to ream out some holes a little bit to get everything to line up properly.

 

[Unfettered Might]

I have to say, I have actually seen more failures on the aluminum crossover intakes than the all plastic ones. That is probably due mostly to more of them being on the road, but the reason for the failure is exactly the same as why the all plastic ones failed. The plastic becomes hard and brittle from the heat of the engine and the coolant running through it, and eventually it will crack. Dirty old coolant certainly can't help the problem, but I have seen the same failure on well maintained cars with clean coolant, so I consider it to be just the normal lifespan of the intake manifold. If you buy a new intake with the aluminum crossover, figure that it will last 8-10 years, which for the price of an intake manifold and the time it takes to change it, is really not bad, and unless you know you will be keeping the car for more than the next 10 years, probably not worth spending twice as much. That being said, if you did want a permanent solution that you will never have to mess with again, the Typhoon intake might be a good solution, but I would want to hear from other people who have installed them first to verify the build quality. Professional products basically makes cheap chinese knock-offs of other brand-name products, and I know with the typhoon intake that I put on my 393 stroker, the performance was great but it took some time fitting it to the car due to some of the bolt holes not being in exactly the right places, and having to ream out some holes a little bit to get everything to line up properly.

You bring up a good point, build quality. I can get one from Performance Products and then there's the one at Autozone made by Dorman. Is Dorman ok or just crap? Is there a source you would recommend?

 

[XR7-4.6]

Crap!!!!!!!!!!!!

 

[stay_unique_91]

The plastic intakes with the aluminum crossover can fail, but the failures I've seen (posted here) in the last 4 years have been few enough to count on one hand. Usually it's the seals between the aluminum and the plastic where it contacts the head. You can avoid this by avoiding used intakes and by changing your coolant regularly.

Nitrous back fire like me that will make it fail. I bought my PI intake a couple years ago from eBay. $200 shipped to my front door. I had a used one before that from a Crown Vic and I broke the coolant jacket that connects the heater core to the manifold the day I finished the swap. I went WOT a few times to try it out and it broke. I also noticed when I went to a brand new one that the car just performed better. I can't prove it though.