IAT sensor relocation: worth it on LT1?
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
IAT sensor relocation: worth it on LT1?
Is it worth it to relocate the Intake Air Temperature sensor from the plenum to the air cleaner box on an LT1? I thought I read in a past thread where the '94 - '96 LT1's and '96 LT4's ECM/PCM is setup such that relocating the IAT doesn't yield any benefit. I can't find that discussion thread now...
I thought the conventional wisdom was that the stock plenum location of the IAT caused the ECM to set the mixture slightly leaner than necessary (emissions-friendly mixture) due to the higher heat in that location, so relocating the IAT to the cooler airbox location would cause the ECM to set a more performance-friendly mixture. Just need to know if this is the correct scenario on '94 - '96 LT1.
[Modified by Lone Ranger, 9:52 AM 7/10/2002]
I thought the conventional wisdom was that the stock plenum location of the IAT caused the ECM to set the mixture slightly leaner than necessary (emissions-friendly mixture) due to the higher heat in that location, so relocating the IAT to the cooler airbox location would cause the ECM to set a more performance-friendly mixture. Just need to know if this is the correct scenario on '94 - '96 LT1.
[Modified by Lone Ranger, 9:52 AM 7/10/2002]
Melting Slicks
Joined: Jan 2000
Posts: 3,418
Likes: 1
From: NW Chicago Suburbs
Re: IAT sensor relocation: worth it on LT1? (Lone Ranger)
My buddies that dabble in PCM program tell me the reason why the classic L98 mods (MAF screen delete, IAT relo, AFPR) don't work on the 94-96 LT1/4 is that under part throttle the PCM uses the O2 sensors as the primary input for injector pulse width (essentially the A/F ratio). The IAT and MAP readings are ignored.
At WOT the PCM then extrapolates the injector pulse width using the part throttle MAF reading to calculate the WOT injector pulse width. So the IAT sensor doesn't really do much unless the MAF fails. When/if the MAF fails, the PCM goes to speed density mode where MAP and IAT readings are essential.
Eric
At WOT the PCM then extrapolates the injector pulse width using the part throttle MAF reading to calculate the WOT injector pulse width. So the IAT sensor doesn't really do much unless the MAF fails. When/if the MAF fails, the PCM goes to speed density mode where MAP and IAT readings are essential.
Eric
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: IAT sensor relocation: worth it on LT1? (silver & red CE)
Yep. After posting I did some research around the net and that's pretty much what I discovered-- ECM doesn't use the IAT except as a backup. Thanks, though.
