IAT relocation?
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Joined: Mar 2003
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From: Oakland Ca.
Car: 1988 GTA
Engine: 5.7L/L98
Transmission: 700r4
IAT relocation?
I saw on e-bay an IAT relocation kit, the seller spouting about engine temps where its located creating retard (maybe the only retard is the one who buys this thing) in the ignition timing due to high temps given off from the motor. Any truth to this, any advantage relocating the IAT sensor. I would think the manufactures engineers might have thought of that when they chose the location in the first place.
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Joined: Apr 2001
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
You're exactly correct. It would not be good.
The IAT tells the ECM what the temperature of the air is that the engine is taking in. Putting the IAC somewhere else would only lie to the ECM.
Doing that would give incorrect O2 sensor readings and possibly cause knocking which would cause the ECM to retard the timing to take out the knock. This will eventually cause an SES light I'm sure.
Even if it didn't do any of the above, it would cause problems with the catalytic converter. The rich mixture would cause a lot of carbon build up and shorten the life of the converter. Not good if someone has emission tests to pass.
The best way is to simply draw in cooler air. Routing the ductwork to the air cleaner is the best way.
The IAT tells the ECM what the temperature of the air is that the engine is taking in. Putting the IAC somewhere else would only lie to the ECM.
Doing that would give incorrect O2 sensor readings and possibly cause knocking which would cause the ECM to retard the timing to take out the knock. This will eventually cause an SES light I'm sure.
Even if it didn't do any of the above, it would cause problems with the catalytic converter. The rich mixture would cause a lot of carbon build up and shorten the life of the converter. Not good if someone has emission tests to pass.
The best way is to simply draw in cooler air. Routing the ductwork to the air cleaner is the best way.
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Joined: May 2003
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From: Hudson Valley, NY
Car: surprise!! a '92RS!!!
Engine: L03
Transmission: 5 speed "M39"
When I installed my open element, an IAT relo was mandatory (no place to put it). I pulled it over to the left (pass side) about 6 inches and zip-tied it to one of the A/C lines.
Yeah, I realize the limitations caused by the engine breathing hot underhood air, and I agree with the previous post totally, but that's what I did.
I'm pretty sure the IAT is in a slightly cooler place where it is than inside the aircleaner housing sitting on top of the engine, but I doubt it's enough to cause any problems.
The zip-tie was about 3c. Bet that's less than the kit you mentioned...
Dean
Yeah, I realize the limitations caused by the engine breathing hot underhood air, and I agree with the previous post totally, but that's what I did.
I'm pretty sure the IAT is in a slightly cooler place where it is than inside the aircleaner housing sitting on top of the engine, but I doubt it's enough to cause any problems.
The zip-tie was about 3c. Bet that's less than the kit you mentioned...
Dean
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I relocated mine on my '86, and it made no apparent difference whatsoever. It didn't harm anything, and didn't gain anything that I can tell.
If you're interested in trying it, you can move it for about $20 (including a new MAT sensor). Just follow this:
MAT Sensor Relocation.pdf
Presumably, on a speed-density system, the lower temperature indication can help with a more correct mixture. On the MAF system I have, it made no noticeable difference. That makes more sense, since the MAF system rely almost solely on the CTS, TPS, RPM, and MAF readings for fuel control, basically ignoring the MAT.
Oddly, the factory later realized that the plenum leaches heat from the engine and sends false high MAT/IAT readings to the ECM. The MAT was moved off the plenum and out to the intake ductwork on LT1 (and later, LS1) engines to correct this problem.
If you're interested in trying it, you can move it for about $20 (including a new MAT sensor). Just follow this:
MAT Sensor Relocation.pdf
Presumably, on a speed-density system, the lower temperature indication can help with a more correct mixture. On the MAF system I have, it made no noticeable difference. That makes more sense, since the MAF system rely almost solely on the CTS, TPS, RPM, and MAF readings for fuel control, basically ignoring the MAT.
Oddly, the factory later realized that the plenum leaches heat from the engine and sends false high MAT/IAT readings to the ECM. The MAT was moved off the plenum and out to the intake ductwork on LT1 (and later, LS1) engines to correct this problem.
Last edited by Vader; Mar 31, 2018 at 09:59 PM. Reason: Updated links
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From: Oakland Ca.
Car: 1988 GTA
Engine: 5.7L/L98
Transmission: 700r4
Thanks guys! I think I will pass no point in messing with it if it's not proven to help. I hate all these claims manufactures make and I am a sucker for the easy cure to anything. I actually bought into the Tornado and installed it. No noticable difference it actually seemed to hinder performance a little. So I started thinking about it more and watched the infomercial, I realized none of there testing ever shows a TPI setup anywhere, people claim to get gains from cutting the screen out of there MAF so I thought if that helps how can sticking this cookie cutter into my air ducting and thinking that the air will continue to swirl at a higher velocity after it passes my TB goes up and around my plenums, through my manifold and into my cylinders? My 
flag went up so I pulled it out and she actually seemed to breath better.
I also bought a TB bypass kit and slapped myself when I saw it and realized I could have purchased the same stuff from my local hardware store for about an 1/8 of the cost
Haven't installed it yet. Any comments on this. I am glad I found this board to ask questions before wasting my money and time, some of you out there are just awesome with your knowledge of these cars particular systems:hail:
flag went up so I pulled it out and she actually seemed to breath better. I also bought a TB bypass kit and slapped myself when I saw it and realized I could have purchased the same stuff from my local hardware store for about an 1/8 of the cost
Haven't installed it yet. Any comments on this. I am glad I found this board to ask questions before wasting my money and time, some of you out there are just awesome with your knowledge of these cars particular systems:hail: 
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
On MAF TPI cars the MAT sensor is only used to enable the EGR. Relocating the MAT to the air intake will in effect disable the EGR. The MAT (now IAT) no longer reports a high enough temperature for the ECM to enable the EGR.
RBob.
RBob.
Thread Starter
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Joined: Mar 2003
Posts: 864
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From: Oakland Ca.
Car: 1988 GTA
Engine: 5.7L/L98
Transmission: 700r4
OK I am learning something. The IAT and MAT are essentially the same animal different names? What years had which? So when tempertures get to (X) amount it kicks in the EGR? I know EGR stands for exhaust gas recirculation but what exactly is its function once it is activated?
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Emission Gas Recirculation Systems, Doug Vidler, Underhood Service, October 1997
The pressure was on beginning in the late '60s and early '70s to improve fuel economy ratings and reduce emissions. Simply put, one way to get improved mileage was to lean the mixture. The idle circuit of the carburetors got the most attention. After being precisely set, caps or plugs were installed over the idle mixture screws to limit the amount of travel, thus in theory, keeping the idle mixture settings "permanent." The "additional" oxygen from the leaner mixture raised the combustion chamber temperatures and combined with the nitrogen forming nitrogen oxide (NOx).
The purpose of the exhaust gas recirculation process was to simply put a small, carefully metered amount of exhaust gas back into the combustion chamber. Exhaust gas has already spent its fuel, so to speak, and is considered an inert gas and will not support combustion. This precise amount of recirculated inert gas slows the burning process in the combustion chamber where NOx is produced. Slowing the burning process lowers the temperature during combustion, thereby reducing or eliminating nitrogen oxide production. This action is most needed during cruise conditions and not at idle or heavy throttle conditions. Some may still incorrectly believe that the EGR is supposed to recycle the exhaust gas - burning it twice must be enough to reduce emissions, right? Wrong.
We just said the exhaust gas won't support combustion - it's already been burned. So, the main purpose? Reduce NOx. The side benefits? Better fuel economy for one, and maybe performance as well. Consider some of the advanced strategies for EGR flow control on some of the later engine applications. The inert exhaust gas actually displaces a small amount of space in the combustion chamber, which in turn reduces a small amount of volume that the air/fuel charge occupies. This can have an effect on fuel economy, albeit slightly, if the EGR valve is malfunctioning.
The purpose of the exhaust gas recirculation process was to simply put a small, carefully metered amount of exhaust gas back into the combustion chamber. Exhaust gas has already spent its fuel, so to speak, and is considered an inert gas and will not support combustion. This precise amount of recirculated inert gas slows the burning process in the combustion chamber where NOx is produced. Slowing the burning process lowers the temperature during combustion, thereby reducing or eliminating nitrogen oxide production. This action is most needed during cruise conditions and not at idle or heavy throttle conditions. Some may still incorrectly believe that the EGR is supposed to recycle the exhaust gas - burning it twice must be enough to reduce emissions, right? Wrong.
We just said the exhaust gas won't support combustion - it's already been burned. So, the main purpose? Reduce NOx. The side benefits? Better fuel economy for one, and maybe performance as well. Consider some of the advanced strategies for EGR flow control on some of the later engine applications. The inert exhaust gas actually displaces a small amount of space in the combustion chamber, which in turn reduces a small amount of volume that the air/fuel charge occupies. This can have an effect on fuel economy, albeit slightly, if the EGR valve is malfunctioning.
Thread Starter
Senior Member
Joined: Mar 2003
Posts: 864
Likes: 1
From: Oakland Ca.
Car: 1988 GTA
Engine: 5.7L/L98
Transmission: 700r4
Thanks Aj informative article. Now I know what an EGR does. I can see how it would improve emissions and maybe save fuel due to less volumetric space to burn it but outside of keeping the internal combustion tempertures lower which could increase incoming air density but enough to make up for the lost space to increase power? Hhhmmm! I love my TA but sometimes I just want to go back to having something built in the 60's for simplicity of design, cleaner engine bays, no emissions requirements. The more I stay on this board and ask questions the less my car intimidates me however. Knowledge is king!
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