what is the 325i TB bore size

[mcgrath]

What is the m20B25 i throttle body bore size?

Thanks,
Steven

[Budget Beater]

i am curious also, i know E36 one is 64mm. I am getting one in soon and getting a digital caliper soon so i can measure it down to fraction of a mm but that won't be for a week or so.

[Stu]

I believe it is 50mm for the E and 60mm for the I

[mcgrath]

ok i got my lazy ass out to thr car last night an measured. my old E TB measure 55mm and the i measure 65mm. I was looking into buying an m30 tb but so far the only ones i have found are 65mm also.

[Stu]

That can't be right. What are you using to measure? Are you measuring from one tip of the butterfly to the opposite tip? M50 24v engines use 64mm throttle bodies, no way an M20 uses a larger plate.

[mcgrath]

I am measuring the inside bore of the throttle body. I used a clear plastic ruler. I measured from one inside wall to the other inside wall at the center. I just went and checked again and it is 65mm. I am trying to find my caliper, if i do I will measure it again.

[Budget Beater]

that doesn't sound right, the housing of the M20 TB looks smaller than the E36 one. i highly doubt the M20 TB is larger than a E36 M3's. the opening is angled not straight cut.

[mcgrath]

Who cares if it sounds right thats what it measures out too. I have no idea what the size is of an m5x throttle body. If the m20 was angle cut then how could you get the throttle plate in?

[mcgrath]

I checked the eta throttle body on the back side and it was 1mm smaller. So I would guess that the i tb would be 64mm. Unless someone else can confirm it I will accept it as that size untill I can find my caliper.

[Stu]

You measured an Eta throttle plate to be 1mm smaller than an 'I' plate?

[mcgrath]

no, the eta throttle body measures 55mm on the front side and 54mm on the back. the i throttle body measures 65mm on the front side so I will assume it's 64mm on the back.