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E30 325is Throttle Body Question (Megasquirt)


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Tonight I was test fitting together my intake manifold as part of my Megasquirt conversion. And have a couple questions concerning my throttle body.

The throttle body I have came with the "air pump" and associated hoses discussed in the thread linked below.


Looking at the Real OEM diagram


I understand the important thing is to supply vacuum to the brake booster. I also get that I need a check valve in that line. That's easy.

Those two lines came from the ports shown here:


But for what was this port originally used? The one under the barb connection for the IAC. It doesn't appear on the Real OEM throttle body pictures that I've looked at. The smaller port I will either use for vacuum sensing or cap off. Just not sure about the larger one..




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I am planning on using the port on the runner for the brake booster and the little port next to where the IAC is for the FPR vacuum connection. Then I think I will use either the small port on the throttle body or one of the two on the manifold for MAP. It's the big hole that I am wondering what it was originally used for. I am not planning on using it at this point, but toying with the idea of tapping the hole and mounting the IAT sensor there. It is just after the throttle butterfly and I haven't measured to really see if that is an option yet.

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