Somewhere on EVOm there was a discussion about the speed of the AEM air temp sensor. I made a comment that I'd test it and forgot about it.

Today I was on the dyno with my RS again and I remembered it when I was logging the car.

So here's what I did. I got a new sensor off the shelf. Plugged it into the cars wiring harness and hung the sensor over the front of the car in front of the headlight.

The sensor was in the box, new so we must assume that whatever the sensor was reading at this time was ambient air temp.

I have a small weather station next to my dyno. Just a basic thing I bought somewhere with temp/humidity/baro on it. That was reading 86 degrees and 60% humidity when I was doing this test on the sensor.

I started a log with the car off (not running). The Air temp with the sensor just reading the air was exactly 100 degrees F. This was quite a bit higher than what the actual tempurature was, so the sensor obviously isn't exact, a difference of 14 degrees to what the weather station was reading and I think 86 degrees is close to what it is today.

So anyway, the question is how fast is the sensor. That's what we care about in this discussion.

On the log the time was 13.960 and the air temp was 100.4 degrees F. I had our dyno fan on and blowing towards the sensor at this time and the temp was dead stable.

I wanted to cool it off quickly, so I took a can of brake clean, which was also on the shelf and just quickly sprayed the sensor, as soon as the brake clean hit the temps drop as I was watching the computer screen when I did it.

Starting time 13.960 and 100.4 degrees
14.28 98.6
14.50 96.80
15.28 95.00
16.72 93.20

So in less than 3 seconds the temp dropped 7.2 degrees.

I then turned and put the sensor in front of the fan.

Time 18.56 91.40 degrees
22.18 82.40 degrees

So in 3.62 seconds it dropped another 9 degrees.

I then just held it there and the temps stayed at 82.40 degrees until I was getting bored and was trying to think how to make them raise back up.

I took the sensor and held it in my closed hand and blew into it (I have a LOT of hot air

Time 28.12 84.20 degrees
31.96 104.00 degrees, it peaked there and would not go up.

In 3.84 seconds the temps increased by 19.80 degrees and was maxed out and stable at that point.

I think that shows how quickly the sensor actually reacts and is most relevant to the testing and such we all do.

To compare this to a log today from my car while it was on the dyno.

The time I started logging was .000, the air temps read 98.60 degrees. The throttle went to WOT at 1.50 seconds into the log, at that point the air temps were still 98.60 degrees. At 7.80 seconds into the run the air temp rose to 100.4 degrees. At 8.78 seconds into the log the air temp rose to 102.2 degrees. At 10.16 seconds into the log the air temp rose to 104.00. The pull ended at 11.06 seconds and the temps maxed out at 107.6 degrees.

The car was in boost (making heat) from 1.70 second until 11.06 seconds, that is 8.92 seconds and much longer than any of the testing above that showed large movements in the temps on the sensor. In that 8.92 seconds of the run and boost the car only gained 9 degrees of intake air temp.

As you can see from above I was able to just blow onto the sensor in my closed hand and in 3.84 seconds made it change 19.80 degrees.

I think this should conclude and doubt that the sensor is too slow for testing.

Should also lay to rest any doubt how absolutely kick *** our Race FMIC is too

This will conclude my air temp sensor testing.

Once again there were no engineers used, harmed or killed during my testing.

 

After putting your intercooler on yesterday I dropped 33 degrees off my AIT temps and was able to achieve an extra 24whp by just bolting it on and an overall 40whp with a boost and timing tweak. thanks Buschur.


RACE FMIC is the ONLY way to go. Very happy. Now I need a CBRD radiator. I actually swithced out my AIT sensor for a new one for I thought it was reading wrong.

Suman

 

Suman, you bought OUR race FMIC? Wow, I am impressed. Thank you but why? I thought you just got one?

 

So you were watching the log, sprayed the sensor, and noticed response immediately in the logs? Sounds like it is pretty quick.

By the way, when ever I turn on my Autronic with the engine cold, the intake temp, coolant temp, and oil temp all read the same, and they all match what the ambient temp is. So it seems odd your IAT was reading 14 degrees hotter than ambient?

Thanks for the test Dave fun to read. Appreciate it.

 

crcain, I agree, if my car is sitting and I turn the key on my coolant and air temps also match and read the same.

Maybe this was just an odd ball, it was new in the box when I grabbed it, rather than taking mine out of my I/C pipe.

 

Fair enough, technical discussion here we come.

David, can you provide me with the thermal conductivity of brake cleaner?

Vapor pressure?

Heat of vaporization?

Chemcial composistion?

How about contact resistance of your hand to the temperature sensor?

Effective radiant heating areas?


I mean, just a few simple numbers and we can make some sense out of the numbers you have.

Other wise, I have a difficult time seeing how spraying a part with brake cleaner has anything to do with the temperature response of the sensor while air is the heat transfer medium.

If these aren't valid technical points, then please let me know and I'll do what I can to stay as technical as possible.

 

03' are you asserting you think the sensors are slow?

So many ECU's use temp comp to retard timing and such, I think it would be surprising if they were slow. David already pointed out when he lifts throttle on pulls he sees changes instantly too. So I think ultimately this was just more info that shows the sensor is speedy.

 

No, I'm not asserting anything. I'm trying to evaluate the data David has provided in a scientific manner.

With just a few numbers, may 15 or so, we could use the scientific data David has provided about sensor response to actually figure out how it would respond to air flow.

You see, the only issue with David's test is he didn't evaluate the response characteristics of the sensor with regards to airflow. He tested it with regards to evaporative cooling and heat conduction. Neither of which takes place in a typical intake where this sensor would be used.

I'm just trying to figure out how to relate David's numbers with numbers that would be more representitive of the actual operating conditions seen in a car.

 

Yes he did sir.. From your #1 stocking Dealer..

33deg drop and 24whp picked up just bolting it on is saying alot about the BR RACE CORES!!!

 

Guys like you are whats makes Dave not even want to post anything on here to help anyone.. People ask questions, Dave goes out of his way to find the answers and still you bust chops..

 

Dave everyday I saw Al, all he ever said was get the Race fmic on and I will show you 40 more hp. I had Mike who has never done me wrong sell me your FMIC and I was stunned. 40hp for 800 dollars is worth a shot regardless of how much *** swinging I hear in my ear at ICS daily. great product like your double pumper and exhaust system. Three things I would not get anywhere else or replace on my car.

PS 652/487 on Pump/meth dynojet which was just under 600 on a buddies Mustang. An easy 138 trapper if I say so myself. Will know on Sunday.


S

 

IBTL and grabbed my popcorn

 

Well thank you very much Suman. Coming from you that means a ton, I know we caught some crap from you last time when you couldn't get our FMIC and ended up with someone else's. So thanks a lot. Sounds like the car should fly with that power for sure. Good luck at the track.

 

thank you man....


PS it spooled 300 rpms quicker also lol.


S

 

Doing a test would be good, do it in a controlled environment too. Make sure there are no a/c vents/heat vents in the building you do it. I also want to know wind speed, ambient temps and humidity at the times you are doing the test as they could effect the outcome. I also want to know the speed of your laptop, the logging rate you perform the test at. I mean, if you are going to do a "proper" test you better get it right and include ALL the information. In your world of perfection the testing had damn sure be perfect when you test it.

Or maybe this test will just end up fading away with the FMIC testing and Intake manifold testing that was going to be performed since other people in the past didn't like how I did my FMIC/Intake testing..........