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View Full Version : how bad is 140 IAC steps?



gcross
January 28th, 2007, 11:01 PM
I've heard that 80 is good for a hot idle. How bad is it for engine to run about 145 steps. It's doing this with a holley 90mm. I'm almost out of room to adjust the set screw to open the blade more. Need some help again. Thanks

Gary

SSpdDmon
January 29th, 2007, 02:14 AM
It's not bad to drill the tb blade a little - especially if there's no more adjustment left with the set screw. My train of thought is this: If you can get it there without having to drill, great! If not, drill a small hole and use the set screw to fine tune it. If the blade wasn't supposed to have an idle hole, GM wouldn't have ordered the TB's with the hole. The characteristics of the car have changed with the bigger intake, cam, heads, etc. Why wouldn't it be right to increase the size of the hole (or add another small hole on the bottom)?

ringram
January 29th, 2007, 02:36 AM
If it drives and idles nice why bother? Just leave it.
The idea of low counts is to let the IAC make large % changes with only small change in IAC counts.
So if its struggling to keep control and IAC variance is pretty large at idle, cracker, follower etc, then yeah drill.

Unless Im missing something important
"if it aint broke dont fix it".

VYSSLS1
January 29th, 2007, 03:15 AM
whenu have this 140 steps is the car in closed loope conditions, and is the iac steps stable.

also what are the specs on the engine, eg camshaft/cubes etc...

SSpdDmon
January 29th, 2007, 03:31 AM
The benefits (IMO) are more for cold-start conditions. If he's at 140 steps during a warmed up idle, how high is he going to be when the engine is cold? That's where you kill the IAC's range of operation.

gcross
January 29th, 2007, 06:15 AM
Well i'm in guam the land that never goes below 75. When I crank the engine in it's cold iac goes up to 160 the drops to 145 when engine goes close loop.

engine 5.7 LS1 with Ls1 hot cam and LS6 intake