Fastbird93

I just found the following links today by chance:
http://www.hashmarks.com/techtips/throttle_body_mod.htm
http://www.chipsbyal.com/idle/tbi.htm

They finally showed me what all my searching on here failed to describe in a good picture. I need to drill a hole between the entry/exit IAC tubes.

So, who has done it and what has it done for you??? I'm noticing that both sites recommend a 11/64" hole to be drilled. How big of a hold did you guys make??

Reason I ask is because I have the BBK 58mm and am running a very agressive custom cam, which is causing me a 100% fuel trim split at idle (allegedly). I'm hoping this will help to cure it some.

Mikey97Z

I drilled my AS&M TB. It helped a lot. Mine looks exactly like the pics in your second link there. I made the filler piece from two-part epoxy putty. It's holding up great. Molded it while soft, machined it after it hardened, and sealed it in with some ultra copper. For the hole I started witha small bit, then drove around some, then made the hole bigger .... it took a few tries. I would recommend just drilling till the IAC counts come down to about 50 at normal temps. I got mine down to like 20, then developed a small vacuum leak somewhere and then my car idled too high because the IAC went to 0 easily.

Fastbird93

Good info, thanks for the reply. I think I'm going to start with the stock 11/64" bit and move from there. It's on a 355 with a pretty healthy custom cam that's been giving my IAC fits (and me too).

NJLT1SS

I will have to try this trick on my AS&M 58mm, see if it helps my LTFT's at all, which are pegged at 160.


Nick