MAC Performance Throttle Body & Intake Plenum with Spacer
Breath-ability is your car's performance best friend. When you start to modify your Mustang, you want to be able to get as much air in, and allow it to escape just as easily. Installing a high performance straight shot filter and intake tube is the best place to start followed by a freer breathing exhaust. An X-pipe/Catback combination really rounds out the mods from front to back.
With these enhancements in place, there is one thing left to do that will significantly improve the performance of the 4.6L GT motor. A larger Intake Adapter Chamber and a larger throttle body. This article will deal with the installation of both.
The stock intake chamber for the 4.6L is really an inefficient design with how sharp a 90 degree corner the air takes before entering the intake manifold. There are several options on the market for the 4.6L and most of them are very close on the hp improvements they provide. You choice will come down to your price consideration and looks. Some of these choices are painted, some are a satin finish right up to polished and chromed items.
We have been fortunate to work with MAC Performance and will be installing a polished Intake Chamber and a MAC 75mm throttle body.
We also purchased a 1/2 spacer plate, but this will require several hours of grinding with a Dremel tool to port the Intake to the plate properly.
Let start by demonstrating the stock arrangement and indicating what the various components are that you will be dealing with.
To begin, we won't remove anything until we have ported the opening properly to match. Air is affected by several factors such as Parasitic Drag and turbulent flow. There is not much you can do about Parasitic Drag except scrap the stock rubber intake tube for a high flow intake. Turbulent flow however, can be minimized by removing all the areas where airflow gets disturbed. When you mate the throttle body to the intake chamber or the intake chamber to the plate, feel with your finger if there is any lips that the air had to travel over on it's way to the engine. Those are the areas that we will remove as much as possible to minimize disturbing the flow of air. The best way to really know how much you will remove is to trace around the openings of the intake chamber and the spacer plate with a market pen. Put the two together as they would be assembled and scribe with enough pressure to make a mark.
Both sides of the spacer needs to be ported but we won't be able to mark the engine side until the stock intake chamber is removed. When you are grinding material off with the Dremel, tilt the Dremel at an angle so that you are only remove material to about the 1/2 point thickness area. Then we we can scribe the other side, we can turn the plate over and match up the two sides of the plate.
Now that we have completed all the porting that is required, we are going to start removing the stock intake to make room for the new install. Start by loosening the intake tube clamp at the MAF as well as the one right at the stock throttle body. There should be enough movement and room to back it off, out of the tube adapter the mates it to the throttle body.
On the drivers side of the intake is the EGR valve assembly (refer to the first photo for identification). Loosen off the pipe fitting and remove the tube from the EGR valve. There are 2 bolts that mount the EGR to the intake. Remove this and carefully remove the EGR valve. If the graphite gasket is partially stuck to the intake and the rest came with the EGR valve, you will need to get a new one from your local Ford dealer. Cost me about $2.30. After the EGR is removed, go to the opposite side and remove the 4 bolts that hold the throttle body to the intake chamber.
