Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Throttle Body

Hey everyone, Im lookin to get a bigger throttle body for my CSVT, and was wondering what size, and where would I find one. Thanks

65mm mustang gt TB...96-98 years...frowned upon unless your running FI or 3L, or have a lot of mods including exhaust and intake mods.

I just have a Bassani cat-back and injen intake, also how much of an increase will a 65mm mustang gt TB give me. Thanks a lot

most say you'll lose HP...but im still gonna try it.

I personally do NOT buy into the "losing" philosophy at all. With mods I feel the GT TB WILL give you more power up top.

what about optimizing the tb? is it worth the time, or just get a bigger tb?

I just think you're wasting your money

why don't you go get some super duper spark plug wires, and new coils while you're at it...that'll help

A stock 65mm t-body bolted on a 2.5 Duratec is not really a good idea for a no. of reasons. The main reason is that it's simply not an apples to apples mod. Although the flange is the same, there are notable differences which preclude it from working properly.

First, the cable fulcrum is different-which means that XX amount of movement in the cable will not translate to the correct amount of rotation at the TPS. This means the PCM will be getting incorrect info. Next problem is that the Mustang uses a helper spring external from the t-body while the SVT t-body has a double return spring integral to the shaft/fulcrum assembly. The cable approaches from the top, not the bottom of the fulcrum, the air bleed hole in the plate is larger and then there's the sealing problems at the top of the SVT UIM. Plus, there's no built in shaft/plate stop like the SVT t-body.

Now a no. of these issues can be overcome reasonably easily, but others are not so simple. I HAVE gotten a 65mm to operate properly on a 3.0, but it meant combining parts of a 60mm (fulcrum & springs) with a 65mm (casting, plate, & shaft), a custom fabricated adjustable throttle stop and custom stamped gaskets. As you can imagine, there was plenty of custom machining and fitting to do to make it work properly, but it does work.

Now on a 2.5... I would have to see back to back dyno results to prove it's worth, if there is any. I know that the custom overbored 62mm certainly "woke up" my sorta' stock 2.5. An optimized 60mm is certainly a cost effective and worthwhile mod.

Brad some good points there, but some wrong ones too:

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First, the cable fulcrum is different-which means that XX amount of movement in the cable will not translate to the correct amount of rotation at the TPS. This means the PCM will be getting incorrect info.

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This is simply wrong. The TPS is connected directly to the shaft which is connected directly to the butterfly. Hence the voltage reference vs. the angle of the butterfly will remain unchanged when converting from the SVT TB to the GT TB. Think about it. Sure the "cam" on the two TB is different. That only changes the amount the butterfly opens with regards to the amount the pedal is depressed, but the ECU is blind to this as there is no reference to the pedal movement.

You are correct though in that the 65mm GT TB need some customizing to make it work on the 2.5L engine, like positive stops etc.

In the end the BEST option for a modded 2.5L for simplicities sake is to optimize the SVT TB - the gains won't be nearly as much but then again the airflow through the SVT TB is probably more than enough for a non F/I 2.5L engine.

For a 3L a 65mm, IMHO, is the best option.