Thread: Is your IAT sensor hurting performance? Find out here!

Q: What exactly changed from the Generation 1 kit and the Generation 2 Kit?



A: Our original prototypes were actually the same as our new Gen 2 kit but at the time the cost was so high that we would not have been able to meet our $100 original price point so we looked to another manufacturer and had them produced. When we contacted the original manufacturer again roughly two years later the price per unit in quantity had fallen so much that we were not only able to go back to the original design but also lower the price.




There actually 89.99 now...GOD why do you always have to be so WRONG!!! LOL

Originally Posted by IndeedSS

A couple of people have referenced what effect the IAT has. I don't have time to to say much about my thoughts right now, other than to post a stock s/c 3800 IAT versus spark table.



All other "visible" calculations are based on ECT not IAT. As for me, unless it is 104* outside, this table is not going to effect my engine.

Just give me the coolest air I can get, when IC'd or not.

ok lets use this example...you are running an open cone filter or cold air and you are suffering from heat soak at the track....with the open cone,temps can easily reach 175 on the iat.consistintly


With our experiment with the icewater mentioned eariler in this post it took the sensor aprox 15 seconds to react and be accurate to a 50 degree temp change


so lets say your iat is reading 175 wich means the pcm is pulling 2 DEGREES OF TIMING because of that.lets also say it is 80* outside...thats a 95* temp change between ambient and iat...so your looking at at least 25-30 seconds before the iat will be reading actual ambient temps (if that were possible with an open cone) .....and lets even say your iat is still reading 175 with an open cone or cold air intake you would have to get the iat temps below 104 for the pcm not to be pulling any timing...thats still a 71* temp chage from the 175*...also at least 16 seconds............




we are mainly talking about performance on the track and not the street...bottom line you are done the 1/4 in 16 seconds and we all know how generally more timing is better...so what if you losing 2 degrees because of a ''slow'' sensor when you could be taking advantage of the additional timing??


2 degrees of timing will,without a doubt hurt 1/4 performance in some shape or form.


We all hear about people putting smaller pulleys on there car and mods ect to make it faster....but what if there was a gain....any gain whether it be a 2 tenths or a thousanth of a second in the 1/4 mile...from changing out a sensor?


it's a small step that could help us out in some way...so why not??

If you are racing in 80*+ weather, you can have all of your timing and I doubt you will run a PB unless you added ALOT to the car after the previous track outing, or its your first time to the track.

If you do a cool off in the shut down lane and still reach 175* IAT temps, something else is really wrong or you are hot lapping.

Sitting in the staging lanes is what does it. I can hot lap the car and pull in better times the second or even third time around before I go to let it cool off.

Your car should be off in the staging lanes with the hood up. When the track official calls your lane:

Close your hood
Get in
Put on helmet
Start your car
Pull forward and get ready to race

You should cool off alot this way. Even more if you have a fan switch. Even more if you have an electric WP.

That's the way it SHOULD be, but not always. That's not the argument here anyway.

Originally Posted by Reptile

That's the way it SHOULD be, but not always. That's not the argument here anyway.

The thing is, it is the arguement. You are saying that the IAT sensors heat up rapidly in the staging lanes. I disagree and said what to do. I will say that you are correct and sometimes something happens and it does not always work out that way. However, most of the time if it does not work out, you end up shutting your car off because you are going to be waiting no matter what.

Anyway, I am doing a mini res of this post cause, of course he would, wizbang made some points about his CAI box and IAT sensors.

If the WizAired CAI System is installed according to the installation instructions and have the air box weatherstripping sealing around the edges, then your engine is breathing air very near ambient air temperatures regardless of what the IAT Sensor is reporting. The reason why the IAT Sensor is not accurately sensing the intake air temperature is because the sensor is horribly designed to accurately measure just the air temperature. Unfortunately, the IAT sensor's sensing tip is not thermally isolated from the sensor's body. Consequently, the sensor's response is highly affected the temperature of the sensor's body, which hangs out in the engine bay. This is especially true if the engine bay is hot and the sensor is allowed to heat soak after driving. The hotter the engine bay, the higher the temperature of the sensor's output (induced temperature measurement error). Another problem with the OEM sensor is its response time to temperature changes. When we would rapidly change the intake air temperature, we reported a slow response by the OEM IAT Sensor. We discovered these problems with the OEM IAT sensor early in our research and development of an intake system for the GM W-Body vehicles. To resolve this IAT sensor error problem, we abandoned using the OEM IAT Sensor and used a fine wire thermocouple measurement system that uses an ultra sensitive and accurate sensing of the air stream entering the throttle body.

Unless the PCM is programmed with an aggressive IAT vs Ignition Timing Adjustment Table, then the IAT Sensor reading has inconsequential effects on the engine's performance. The OEM IAT Sensor is good enough for the purpose GM designed it for, that being to measure large changes in intake air temperature. It was not designed to accurately measure small changes in intake air temperature. The only benefit of getting the IAT sensor to read the air temperature accurately is for scanning and seeing lower air temperature numbers. If you wished to have your OEM IAT Sensor reading the intake air temperature more accurately, then we would suggest relocating the entire IAT Sensor into the air box and have only the wires/harness protrude through the air box. This sensor arrangement will allow the sensor to be immersed in the intake air and more accurately measure the actual air temperature. However, this relocation will not affect the slow response of the OEM IAT Sensor. That is inherent to the sensor's design.

... Once the components heat up, the flimsy insulation (non reflective and on the inside) does zip.

This statement is absolutely incorrect. The insulation used on the WizAired CAI is highly effective and is has excellent reflective properties. The insulation has a a reflectivity of ~97%. This means it has a thermal emissivity of ~3%. This means it will be very poor at heating the inside air through radiant heat transfer and that's a good thing/property to have in the system. The insulation factor for the material used is ~R4.7. This is approximately equivalent to 1.7 inches of fiberglass insulation used in homes. The insulation is located on the inside of the air box for the variety of advantages it provides over installing the insulation on the outside.

Originally Posted by Sabrewings

Fish, got the thread that came from. I'd be interested to see the rest of the of what Wizbang has to say about the WizAired (since I have one ).

I can post it, but that was his first and only post about it.

ClubGP Message Forum troubleshooting

Excuse the TB spacer comment. I grow tired of people telling me their TB spacer is fine and it wont fail on them only to turn around 3 months later and ask why their TB spacer failed and start spitting coolant into the engine.

OK fellas....I got the new IAT's built over the weekend, and here are a few tests we ran. They consisted of putting them in front of a space heater to simulate a heat soak if you will, also to have a constant starting temperature. Hit it with a can of compressed air to chill them down, then back in front of the space heater just to demonstrate the sensitivity and range of the sensors. The next test was to chill them with the compressed air again, then see how long it would take to return to ambient temperature on their own. The modified sensors clearly recovered faster than the stock ones did.

Also a side note, I'll also add that the modified ones are extremely sensitive to temp change....so much as moving them around in the air and even slightly breathing on them caused variations in temperature....so they're deffinately sensitive enough.

Now the discussion on if they're worth it or not, I'll let you guys be the judge....Sorry about it being in Celsius, try not to bust my balls too bad.

Im assuming there are graphs there. Work blocks photobucket so I cant see. However, Ill be scanning tonight on my way home since I added the LQ4 MAF. One thing that I noticed is that the wiring harness now uses the LQ4 IAT sensor. Which IIRC James was telling me at the dyno day responds alot faster then the stock one. Ill scan IATs for fun.

Good job Brian everything looks as planned....Thanks for all of your help and doing your end of the testing.We couldnt of don it without you and everyone on here that helped out


Worth it???...Absolutely

Heres my scan tonight with the LQ4 IAT. Whats funny is that it was about 35* outside, I have everything set to standard instead of metric but it shows celsius. When I started my car it was ambient. Then it went a little bit lower. Then higher depending on situation. *shrugs*

4-14-08 Scan from Fish -- Scan Depot dot net

Another thing to think about. Why have it go faster?? That is just one more thing to worry about going down the track affecting your timing tables even if they were to reach over 120*F.

Originally Posted by Fish

Why have it go faster?? That is just one more thing to worry about going down the track affecting your timing tables even if they were to reach over 120*F.

Why are we shooting for faster?....I'll tell ya why..The likelyhood of iat temps really being 120* at the lights and all the way down the 1/4 mile is unreal.Because with the old iat (slow) sensor it may be reading that from heat soak and lack of response time.


With the new sensors we are for once actually reading real time info.

If you do a proper cool down the IATs wont be as high or high at all. We saw on the video they take awhile to warm back up. You can easily be shooting down the 1/4 before they get into a danger zone.

Yeah we're probably both right