Drilling out TB Q's???
 

I installed the G5X-2 cam in my car on friday. With the TB drilled out 7/32" it idles at around 750 RPMs. What do you think it will idle at if I drill it out to 1/4"? I don't want to drill it out too much and be screwed. Yesterday it died on me sitting at a red light in traffic. I think it was because I switched both fans on. If I bump the idle that should help, correct?

TIA :burn:

Re: Drilling out TB Q's???
 

Drilling the TB is NOT the way to adjust idle. You need to program the car to idle where you want. Otherwise the computer will be trying to force the engine to idle lower (cut fuel) and it will get REALLY bad.

THEN...using AutoTap see if your IAC count is in the 30s. If its above 40, start drilling one NUMBER bit at a time (not fraction drills). If its below 30 STOP...don't do anything! You want the IAC count to settle in the mid 30s at idle.

Chris

Re: Drilling out TB Q's???
 

Second that, you need something like autotap or efilive to find out what the iac's are at and adjust that way. Use ls1edit( or local tuner ) to get your idle at what you want.
I had NO luck with the drill mod or the set screw that does nothing but drive you insane. Once I got ls1edit and corrected these the right way it was a waste of time.

Re: Drilling out TB Q's???
 

As said above, the drill out mod isnt to change the idle speed, its to let more air in at idle. A cammed car is starving for air breathing through that tiny little hole...the IAC motor either needs to open up more, or you need a bigger hole in the TB. A 1/4" hole will be fine, but I wouldnt go bigger. I had 1/4" in the camaro, it was fine both with and without tuning. For big cams, like the one you have, the IAC probably wont be able to open up enough to feed the motor so the hole isnt that big of a deal, but I'm sure everybody will have differing opinions on that.

Re: Drilling out TB Q's???
 

Thanks for the responses guys! I didn't mean raise the idle, I worded that wrong. I was refering to the IAC. I just thought that they had to do with eachother.

Re: Drilling out TB Q's???
 

ohhhhh....ok...then yeah....your on the right track. Get you AutoTap out and start drilling till the IAC gets down into the 30s.

Just be careful....if you go too big it will also cause problems. Your best using #drills (#40,39,38,37,36,etc..), not fraction drills (1/8,1/4,3/8,etc....). They are not such a drastic jump and you will get a better result.

Chris