porting upper plenum on 4.6..A MUST
 

Guys, if you haven't opened up the upper intake plenum on your 4.6 engines you gotta get it done! There is a whole lot of room left in there and the walls are rougher than pavement! You will notice a difference.

What did you do to yours? Sand them?

While polishing mine for looks ( the outside ) i noticed how rough it was on the inside. I used a die grinder with a sanding wheel with 80 grit and sanded/ported the walls down smooth. then went to finer grit to get a polished finish. It opened it up quite a bit and had to help air flow. It took all of an hour to remove port and replace. I'm sure I could have opened it up even more but I got to where I felt comfortable and left it at that. Also added an intake spacer while I was at it.

Anyone in Michigan wanna do mine for me and make some money?? heheh:D

I was thinking of doing this for awhile I just have 1 ?? it the gasket for the upper reusable or do I need to get a new one


thanks for any help
tony

It's reusable, just a paper gasket. This is super easy! If you have the right tools. I used an air die grinder, you can rent one cheap or use a electric one. A drill won't get you enough RPMs. use the sanding wheel that looks like sandpaper squares glued to a bit. some call it a flapper wheel. Mine had sanpaper with scruber pad inbetween the sheets of sandpaper. Works wonders!

Actually, I just spoke to the shop who tunes my, and many other stangs, about this. He said there was absolutely no power gain or change in power curves on the dyno's from doing this. Also, take too much off the inside and the heat can cause the plastic to crack if there is a weakened wall. This worked well with carbuerated motors. If the walls from the intake were rough, it would cause the fuel and air to seperate. Hope this saves some of you from wasting your time, and or money.

What plastic are you talking about? The upper plenum is made of aluminum.....

I was talking about the lower one. People have tried porting it and they wound up cracking.

As far as this not producing any horsepower, MM&FF dynoed the ported intake vs. stock and got roughly 10 hp &14 lb/ft in May I think.

Unfortunately, no one in the "real world" seems to have done this and dynoed afterward. I've read several posts on this but no one can give us numbers. No offense to anyone associated with the article, but until I read it from more reliable sources (not the butt-o-meter), it doesn't seem like a worthwhile mod.

Actually someone has, check out the link...

http://www.modulardepot.com/articles.php?aid=5

Bill

I stand corrected. Thanks Bill. I know I can always rely on you to provide us with new and correct information. I guess it's not a bad idea, especially those that are good with a dremel. Approximately 3 rwhp isn't bad for the time, or price if someone else does it. That's about half the price of a CAI for the same gains.

I have the drill bit to port and polish but all I have is an electric drill, is that powerful enough?????

DO NOT do this mod on a Supercharged car. I've seen first had dyno losses with the mod.

Just a note....