Free Web Site - Free Web Space and Site Hosting - Web Hosting - Internet Store and Ecommerce Solution Provider - High Speed Internet
Search the Web

One method of increasing the acceleration rates on the 3.0 and 3.3/3.8 is to install a throttle body with a larger diameter

The 3.0 used a stock 46mm TB on the intake manifold. This TB is controled by an AIS and the gas pedal. The gas pedal and cruise control uses two stress cables to control how open the TB is. At WOT- or wide open throttle, the TB is wide open, allowing for the max amount and rate of air to enter the engine. The AIS basically keeps the TB slightly open during idle, while the gas pedal controls the TB whenever the gas pedal is pressed. There are two TB's which can be used with the 3.0 engine. The 52mm TB (found on 3.3's), or the 58mm TB (found on select '98 and newer AWD 3.8's).

When putting a 52mm TB on a 3.0, it may be required to swap with the TB the AIS and TBPS- or Throttlebody Position Sensor. For the most part, the 52mm TB just bolts right on.

The 58mm TB however requires porting of the intake (reguardless as to rather you have the 3.0 or 3.3/3.5/3.8). Basically the diameter of the TB is larger then the diameter of the hole on the intake manifold. After the porting is done, a new gasket is needed (one for the 58mm TB), and the ais, etc also needs to be swaped over.

With the 3.3/3.8, the TB is 52mm to begin with, though a 58mm TB can be swaped on if the manifold is ported to fit like with the 3.0. The main differnce here is that it might actually be possible for the 3.3 to use the 60mm TB found on some Jeeps if enough porting and fabrication is done.

In either case, if this is done properly, the result is faster acceleration, and slight HP increases due to the extra amount of air flowing into the engine.

One 3.0 guy got faster acceleration by running dual TB's. This takes a ton of work and generally dosen't improve things as much as just a larger TB.

TB spacers are out there, and in many cases can be made. The idea is you get more power by getting the air to mix and funnel more before entering the intake manifold. If you try to get a unique TB like off of a mustang or Jeep onto your 3.x, you may want to make your own spacer to help you attach your TB and also to give you some small gains. Some people say something like 10hp from a spacer- but I don't believe those figures much.

There is, not surprisingly, some confusion on this one. I would not be surprised if some people running what they think are 58mm Tbs, are really the 52mm TB. This is because they look the same from the front, even both measure at the front to be 58mm.

You can only tell them apart from the back.

52mm TB to the left, 58mm TB to the right

Note that the 52mm as a half circle taking out of the side of the bore on the top left (in this pic), which the 58mm lacks, that is one possible way to tell them apart, alternately you can use a ruler.

See in this pic (above) that the ruler has two black spots marked with a marker, that is measuring off 58mm, you can clearly see that on the 52mm, the bore is smaller than that.

On the 58mm TB, the bore is exactly 58mm in diameter.

When in doubt, measure.