Tony89GTA

iTrader: (7)

So I was doing some datalogging and I recorded one of my 3 gear pulls and I was little surprised with what I was seeing. I swapped out my intake last week for a miniram and I decided to use a LT1 IAT sensor from a 95 camaro plumed into my intake track with a grommet. I can't believe how quick this thing responded on that 3 gear pull, my intake temps started from 77 deg and as more boost came in it started to climb pretty fast up to 151 deg. Think the last time I bothered looking at that sensor data, my temps wouldn't even climb 3-6 deg on a full boost run but that was with the old stock sensor or possible the v6 sensor with the open cage element, having a hard time remembering.

Orr89RocZ

iTrader: (20)

Yup its nice to see a real sensor doing its magic and real eye opener to see how data reacts with changing conditions.

The stock style coolant sensor look alike MAT on my 89 maf car i reused for my boost car and it usually just showed 1 value which may have been intake metal temp as the thing heatsoaked. Switched to the diyautotune IAT in my intake piping and could see actual changes. It was so nice. 85-90 deg to 125 after 9 sec pull. Could actually use the timing retard vs air temp tables lol

Tony89GTA

iTrader: (7)

Well I always wondered what my intake temps were on a full boost run lol. Guess I'll have to start playing around with new tables like the one you said.

It's been awhile since I researched intercooler efficiency, is 150 deg getting up there?

Orr89RocZ

iTrader: (20)

Yeah 77 to 150 is alot of rise and you may need to consider intercooler changes.

Local import shop tested a 600whp evo with 2 identical sized intercoolers. One was a ultra expensive unit but well known for quality and efficiency. Other was a cheap ebay knockoff look alike. No other changes the expensive cooler barely rose in temps from high 60's ambient during a dyno pull of a few seconds. The ebay cheap cooler rose something like 50-60 deg and ecm started to pull timing based on iat temps. Lost power. Increased chance of detonation.
Good intercooler is worth the price you pay. Mine is midrange and seems to do well enough at 800's hp even tho it says 1300 hp rated. I only saw 20-30 deg rise on warm day 9 second full boost pull at track

Tony89GTA

iTrader: (7)

I'm still running the 3 core Procharger one, guess I'll have to look into options later on. Probably doesn't help though being a trans am and sucking the supercharger air right above the header lol.

Orr89RocZ

iTrader: (20)

Hot in means hotter out lol. Once reason i dont like blowers as most seem to put air intake over the header. Would need a cowl hood and extend intake pipe to get some cold air in. That would help alot i am sure.

project89

iTrader: (1)

if u originally had an open element ait in there and it read slow it was bad

i hate to break it to ya but the 3rdgen v6/ sensor and the other gm open element sensors + the lt1 sensor are all the same . on the other hand there is a huge difference between the closed type that looks like a cts and any open element type ait sensor

anesthes

iTrader: (12)

I noticed this the other day. I ran the car for about 10 minutes in the shop. Found a small exhaust tick on the drivers header. Went to pull the air filter off and burned my hands. The metal screen around the filter was so damn hot.

I have a formula, so I'm going to re-work some stuff and see if I can't move the filter to just under the cowl opening and insulate some stuff.

Btw, I'm using an eagle talon IAT sensor which works quite well.

-- Joe

anesthes

iTrader: (12)

My vette was the worst:

http://members.cisdi.com/~anesthes/s...complete/1.JPG

-- Joe

Tony89GTA

iTrader: (7)

Yeah kind of figured that, but I don't remember if I ever looked at the data when I swapped out the closed style MAT to the open V6 one on my TPI plenum. Does your V6 one move 50*+ in just a few seconds?

project89

iTrader: (1)

yes it does , when i was dataloging at the track i would go from 80* on the starting line to 170ish by the finish line

problem with putting one in the tpi plenum is it will heat soak really bad , i recomend putting a bung in before the throttle body in the air plubing and mounting it there as it wont heatsoak nearly as bad

Tony89GTA

iTrader: (7)

I thought about that myself at one point, grabbing a formula hood and using the cowl area for it, think it would work out great.

I take it this eagle talon sensor has the same resistance and just a matter of a pig tail change?

Tony89GTA

iTrader: (7)

Well that's good to know it acts like it should, then it was definitely the old style sensor I remember with only 3 to 6 deg of movement.

anesthes

iTrader: (12)

Pig tail is the same, but the resistance table needs to be changed.

-- Joe

Tony89GTA

iTrader: (7)

Oh right your using megasqurt.

Six_Shooter

iTrader: (2)

Yes, you need to do something about either the IC or the more effectively the incoming air. Before I put my IC on my car, I noticed a 20 to 30 degree (F) drop in intake temps, just from moving my air filter from the turbo inlet to in front of the rad. I noticed a slight drop even moving it forward (Straight 6 engine) and down just a bit so that the filter was low in the engine compartment and just behind the rad.
Now with the IC as long as the IC doesn't get heat soaked (sitting still too long with the engine running, in the staging lanes) my intake temps will drop back down near ambient on a pass, rising slightly by the end of the pass.

This is NOT the sensor heat soaking, this is the air itself being heated. Air gets heated VERY quickly, as it passes through a heat soaked tube or manifold. So those warmer than you would like to see temps are real. Moving the sensor to a cooler part of the engine bay only makes the person looking at the data happy. This does not help the engine in anyway, or show real data.
People tend to forget that heat can get passed to the air from inside the tube to the outside and from the outside to the inside of the tube.

project89

iTrader: (1)

i wasnt saying those temps werent real i know they were, but when i had my ait inside the manifold plenum it would always be around 110* instead of closer to ambient , and the temps wouldnt drop as fast as when it was in the intake tube instead


i just hit my tpi intake with an infared thermo the other day, the plenum was about 170* so screwing a sensor into that and having it run for a while will scew the reading some

Six_Shooter

iTrader: (2)

Yeah....

Why would you, or better yet the ECM not want to know the actual temp of the air entering the cylinder? The closer to the cylinder you can place the IAT/MAT the more accurate the reading will be of actual air temp (using an open element type).

Your sensor must have been old, or it wasn't updated very often in the datalogging. In my car (and a few others I've tuned) the MAT reports very rapid changes in air temp.
In my own car the MAT is mounted directly behind the throttle body, because it was pretty convenient to mount it there (replacing a cold start injector). I can watch the temp drop by 30 degrees sometimes in about a second, or basically as quickly as the ECM updates the datastream.

anesthes

iTrader: (12)

Because it depends on the programming of the ECM. Some masks are looking for a MAT sensor, which is going to be much higher reading than an IAT. If you run a calibration expecting an IAT, yet run a MAT sensor in the intake manifold it's going to make the wrong decisions.

The manifold is going to be hotter than the actual air charge entering the cylinder. The sensor isn't heat soaking, the manifold is.

-- Joe