Thoughts about LT1 IAT relocation (with numbers)
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Race Director
Joined: May 2001
Posts: 14,165
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Thoughts about LT1 IAT relocation (with numbers)
Most people will tell you that this modification is junk, myself being one of them. Still there are a very few people who say that it's a good mod and gives a more accurate picture of the "real" air temperature. Note I am referring here to the LT1 where the IAT is located in the rubber duct, NOT in the metal intake. The L98 MAY be different but I would have to data log one to find out.
The claim is that by relocating the IAT closer to the air filter, you get a more accurate reading because the sensor is not affected by heat soak.
I say that you want the sensor as close to the air going into the cylinder as possible because that will give you the most accurate information. People claim that the sensor heat soaks and gives a false warm reading, I say the air is moving so fast, that it keeps the sensor cool and doesn't have time to heat soak anyway.
To prove my point, I was just looking at some data logs. The first data log is from a 12 minute drive to work.
The data log starts with engine temperature at 66.7*F and IAT temp at 68.9*F. Due to manufacturing tolerances and physical location differences, I think you could call that "the same." The car had been parked in my cool garage overnight. 12 minutes later when I parked the car, the coolant temperature was at 188.2*F and the IAT was at 70.5*F.
Ok, so you're saying that 12 minutes isn't enough for it to heat soak, enter data log #2.
This data log begins with the car in my parent's heated garage. Engine temperature is 62.6*F, IAT temp is 65.5*F. No more than backing the car out of the garage, the IAT temp drops to 48.2 degrees. 45 minutes worth of highway cruising later, the engine temp is up to 188.2*F and the IAT is up to 51.8*F.
So what's my point? SAVE YOUR MONEY ON THE IAT RELOCATION KIT. Even if the sensor "heat soaks" at idle, as soon as you open the throttle blades and air actually moves through the intake tract, it's gonna cool the sensor right back down.
Now I'm sure that somebody will want to dispute what I've posted here. If you feel inclined to do so, please have something to back it up with other than "I ran .2 seconds faster at the track." Unless you did 20 back to back passes on the same day and swapped the IAT location on every run, your "data" is likely meaningless.
The claim is that by relocating the IAT closer to the air filter, you get a more accurate reading because the sensor is not affected by heat soak.
I say that you want the sensor as close to the air going into the cylinder as possible because that will give you the most accurate information. People claim that the sensor heat soaks and gives a false warm reading, I say the air is moving so fast, that it keeps the sensor cool and doesn't have time to heat soak anyway.
To prove my point, I was just looking at some data logs. The first data log is from a 12 minute drive to work.
The data log starts with engine temperature at 66.7*F and IAT temp at 68.9*F. Due to manufacturing tolerances and physical location differences, I think you could call that "the same." The car had been parked in my cool garage overnight. 12 minutes later when I parked the car, the coolant temperature was at 188.2*F and the IAT was at 70.5*F.
Ok, so you're saying that 12 minutes isn't enough for it to heat soak, enter data log #2.
This data log begins with the car in my parent's heated garage. Engine temperature is 62.6*F, IAT temp is 65.5*F. No more than backing the car out of the garage, the IAT temp drops to 48.2 degrees. 45 minutes worth of highway cruising later, the engine temp is up to 188.2*F and the IAT is up to 51.8*F.
So what's my point? SAVE YOUR MONEY ON THE IAT RELOCATION KIT. Even if the sensor "heat soaks" at idle, as soon as you open the throttle blades and air actually moves through the intake tract, it's gonna cool the sensor right back down.
Now I'm sure that somebody will want to dispute what I've posted here. If you feel inclined to do so, please have something to back it up with other than "I ran .2 seconds faster at the track." Unless you did 20 back to back passes on the same day and swapped the IAT location on every run, your "data" is likely meaningless.
Last edited by Nathan Plemons; Jan 21, 2009 at 09:26 AM. Reason: Typo
Melting Slicks
Joined: Nov 2004
Posts: 2,799
Likes: 2
From: Cape Coral FL
Most people will tell you that this modification is junk, myself being one of them. Still there are a very few people who say that it's a good mod and gives a more accurate picture of the "real" air temperature. Note I am referring here to the LT1 where the IAT is located in the rubber duct, NOT in the metal intake. The L98 MAY be different but I would have to data log one to find out.
The claim is that by relocating the IAT closer to the air filter, you get a more accurate reading because the sensor is not affected by heat soak.
I say that you want the sensor as close to the air going into the cylinder as possible because that will give you the most accurate information. People claim that the sensor heat soaks and gives a false warm reading, I say the air is moving so fast, that it keeps the sensor cool and doesn't have time to heat soak anyway.
To prove my point, I was just looking at some data logs. The first data log is from a 12 minute drive to work.
The data log starts with engine temperature at 66.7*F and IAT temp at 68.9*F. Due to manufacturing tolerances and physical location differences, I think you could call that "the same." The car had been parked in my cool garage overnight. 12 minutes later when I parked the car, the coolant temperature was at 188.2*F and the IAT was at 70.5*F.
Ok, so you're saying that 12 minutes isn't enough for it to heat soak, enter data log #2.
This data log begins with the car in my parent's heated garage. Engine temperature is 62.6*F, IAT temp is 65.5*F. No more than backing the car out of the garage, the IAT temp drops to 48.2 degrees. 45 minutes worth of highway cruising later, the engine temp is up to 188.2*F and the IAT is up to 51.8*F.
So what's my point? SAVE YOUR MONEY ON THE IAT RELOCATION KIT. Even if the sensor "heat soaks" at idle, as soon as you open the throttle blades and air actually moves through the intake tract, it's gonna cool the sensor right back down.
Now I'm sure that somebody will want to dispute what I've posted here. If you feel inclined to do so, please have something to back it up with other than "I ran .2 seconds faster at the track." Unless you did 20 back to back passes on the same day and swapped the IAT location on every run, your "data" is likely meaningless.
The claim is that by relocating the IAT closer to the air filter, you get a more accurate reading because the sensor is not affected by heat soak.
I say that you want the sensor as close to the air going into the cylinder as possible because that will give you the most accurate information. People claim that the sensor heat soaks and gives a false warm reading, I say the air is moving so fast, that it keeps the sensor cool and doesn't have time to heat soak anyway.
To prove my point, I was just looking at some data logs. The first data log is from a 12 minute drive to work.
The data log starts with engine temperature at 66.7*F and IAT temp at 68.9*F. Due to manufacturing tolerances and physical location differences, I think you could call that "the same." The car had been parked in my cool garage overnight. 12 minutes later when I parked the car, the coolant temperature was at 188.2*F and the IAT was at 70.5*F.
Ok, so you're saying that 12 minutes isn't enough for it to heat soak, enter data log #2.
This data log begins with the car in my parent's heated garage. Engine temperature is 62.6*F, IAT temp is 65.5*F. No more than backing the car out of the garage, the IAT temp drops to 48.2 degrees. 45 minutes worth of highway cruising later, the engine temp is up to 188.2*F and the IAT is up to 51.8*F.
So what's my point? SAVE YOUR MONEY ON THE IAT RELOCATION KIT. Even if the sensor "heat soaks" at idle, as soon as you open the throttle blades and air actually moves through the intake tract, it's gonna cool the sensor right back down.
Now I'm sure that somebody will want to dispute what I've posted here. If you feel inclined to do so, please have something to back it up with other than "I ran .2 seconds faster at the track." Unless you did 20 back to back passes on the same day and swapped the IAT location on every run, your "data" is likely meaningless.
ET is a function of traction... you would look at the MPH for a percieved HP gain, and this particular mod would likely not show a gain in MPH, thus rendering it useless IMO. I'm with Plemons here 
Pro
Joined: Apr 2008
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From: middle of Illinois
Thread Starter
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
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