IAT WITH/WITHOUT for TURBO CAR
I've tuned more without than with. They have accuracy problems and need to be thoroughly tested before you can rely on them. Often having multiple IAT is necessary to make sure the readings make sense. For example an IAT off the compressor telling me 120*F and in the intake manifold 140*F, which is after the intercooler of course. Was it heat soak? I tried another sensor, same result. So we positioned one at the back of the manifold, isolated it, and got the same reading. Turns out the intercooler was completely unecessary, that the air temp would hit 140* no matter what we did before it got there because of the factory intake manifold design. We removed the intercooler and shortened the plumbing, IAT in the manifold dropped to 136*F after that, we picked up 500rpm of usable torque and improved response, which also lowered EGT and exhaust manifold pressure a few psi and increased peak horsepower slightly. Would have never noticed anything was wrong if we only had the one sensor in the manifold like everybody runs, you need a second or third sensor positioned elsewhere to observe and make adjustments to the plumbing for improvements.
Even when working properly, there is very limited functional use in practical application. Most of the time you are adding fuel anyway as the engine heats up to control temperature rise and limit knock in a performance application, whereas the OEM computers will sometimes pull fuel in the hot IAT instead of adding it.
All in all I find them useless here in Florida. It never gets cold enough to require IAT enrichment, the only practical use I can see. And getting hotter just means running it richer anyways. On maybe 50-70 turbo cars I've tuned in Florida, only three or four had an IAT, completely unnecessary here in Florida IMO.
Even when working properly, there is very limited functional use in practical application. Most of the time you are adding fuel anyway as the engine heats up to control temperature rise and limit knock in a performance application, whereas the OEM computers will sometimes pull fuel in the hot IAT instead of adding it.
All in all I find them useless here in Florida. It never gets cold enough to require IAT enrichment, the only practical use I can see. And getting hotter just means running it richer anyways. On maybe 50-70 turbo cars I've tuned in Florida, only three or four had an IAT, completely unnecessary here in Florida IMO.
Last edited by kingtal0n; Dec 2, 2015 at 01:04 PM.
Thread Starter
Staging Lane
Joined: Dec 2015
Posts: 65
Likes: 1
great , and i only plan to drive in the summer anyhow, but im not looking for a perfect reading off hand anyhow, so i should be safe by asking my tuner to just do without, and since i installed the motor the sensor was never installed and motor ran great , im just now going to twin turbos , so we will see how it goes, thanks again
If you are going with a SD setup on a factory PCM you will want to keep it. The PCM uses a combination of IAT and ECT to figure out temperature along with the MAP sensor to determine air mass.
I've tuned more without than with. They have accuracy problems and need to be thoroughly tested before you can rely on them. Often having multiple IAT is necessary to make sure the readings make sense. For example an IAT off the compressor telling me 120*F and in the intake manifold 140*F, which is after the intercooler of course. Was it heat soak? I tried another sensor, same result. So we positioned one at the back of the manifold, isolated it, and got the same reading. Turns out the intercooler was completely unecessary, that the air temp would hit 140* no matter what we did before it got there because of the factory intake manifold design. We removed the intercooler and shortened the plumbing, IAT in the manifold dropped to 136*F after that, we picked up 500rpm of usable torque and improved response, which also lowered EGT and exhaust manifold pressure a few psi and increased peak horsepower slightly. Would have never noticed anything was wrong if we only had the one sensor in the manifold like everybody runs, you need a second or third sensor positioned elsewhere to observe and make adjustments to the plumbing for improvements.
Even when working properly, there is very limited functional use in practical application. Most of the time you are adding fuel anyway as the engine heats up to control temperature rise and limit knock in a performance application, whereas the OEM computers will sometimes pull fuel in the hot IAT instead of adding it.
All in all I find them useless here in Florida. It never gets cold enough to require IAT enrichment, the only practical use I can see. And getting hotter just means running it richer anyways. On maybe 50-70 turbo cars I've tuned in Florida, only three or four had an IAT, completely unnecessary here in Florida IMO.
Even when working properly, there is very limited functional use in practical application. Most of the time you are adding fuel anyway as the engine heats up to control temperature rise and limit knock in a performance application, whereas the OEM computers will sometimes pull fuel in the hot IAT instead of adding it.
All in all I find them useless here in Florida. It never gets cold enough to require IAT enrichment, the only practical use I can see. And getting hotter just means running it richer anyways. On maybe 50-70 turbo cars I've tuned in Florida, only three or four had an IAT, completely unnecessary here in Florida IMO.
Wow, I literally had to put face to palm
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The stock MAF has an integral IAT sensor. SD is speed density. There are 2 ways to determine how much air mass is going in the engine; Measure it with a Mass Airflow Sensor (MAF), or calculate it based on engine size, rpm, VE, manifold pressure, and air temp (SD).
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So did I. His idea of 'its always hot here so I don't need to adjust based on IATs' is incredibly foolish. With a 90+ degree ambient temp, hot track, and no intercooler, a turbo car can see IATs climb over 200 degrees very very quickly. Some will be mid-upper 200s.
Thread Starter
Staging Lane
Joined: Dec 2015
Posts: 65
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