Alternative choices for TB on 3.2 manifold
 

I am putting together a turbo motor which will use a 3.2 intake manifold and aftermarket EFI. My original inclination is to use a stock 3.2 throttle body.
I understand that several vendors sell TPS adapters which can be adapted to the stock 3.2 throttle body. However, I was wondering if anyone has had success with any other readily available throttle bodies.

Thanks in advance.

Rob

You can put an early to mid-'90's TPS from any BMW except the 318i.

You'll need a 0.500" thick aluminum (or other material) spacer/adapter, or shorten the 3.2 TB shaft by same amount. But, you'll still need to account for the different TPS pattern over the WOT switch of the intake.

Not sure if any other TB's bolt right up aftermarket without modification, but '80's Mustang 302 TB's are pretty cheap and feature a 4-bolt pattern, square like the 3.2.

They're probably the cheapest out there.

"you'll still need to account for the different TPS pattern over the WOT switch of the intake."

Hmm, I'm not sure what that means...

Most aftermarket ECU's can use just about any type of TPS sensor. Mustang TB's are readily available from JEGS or Summit Racing from BBK to ACCUFAB. Even eBay. It will require welding up your original bolt holes and re drilling for the new bolt pattern. And then of course the whole linkage adaption. You could take your existing TB to a good machinist and have them open up the factory TB to 75mm and replace the throttle plate, if you want to keep it factory appearing. But then again you are doing a 3.2 manifold conversion so the factory appearance is really out the window.

If you shorten the shaft to put the TPS flat up against the TB like the WOT used to mate to it, you'll still have to modify the TPS or TB to account for the hole pattern difference.

I've always assumed that a 75mm throttle body was too big for a stock 3.3 liter.

GJF I know your engine moves much more air than a stock one but do you think a 75mm throttle body would still work with stock heads and EFI?

Oh, ok. Now I understand about the bolt pattern difference. Thank you.

Why you might as well make a 0.500" adapter. Modifying the TB or TPS would not be fun.