Well today I picked up one of those cheap thermometers with the remote sensor from walmart and decided to do some unscientific investigations. Here is what I did. I compared airtemps between underhood and inside my CAI. I did three comparisons at idle at a stop 55mph and 80mph.

Some background info on the test vehicle (my car)
1. Home made CAI- KN cone filter with Reflectix box no cardboard liner just the foil.
2. Stock coolant bottle in stock location behind the headlight.
3. PCM mounted to the side of the coolant bottle
No other engine mods.

I used the following instruments in my testing
Tach, coolant guage, outside airtemp reading from the car and my remote sensing thermoter.

at idle stopped
outside air temp coolant temp
79F 190
underhood temp= off scale (thermometer only reads upto 158)
CAI=139F

55mph at 1550 rpm
outside temp 79 coolant temp 195
under hood = 120F
CAI= 85F

80mph at 2300 rpm
outside temp 81F coolant temp 192
underhood = didn't check because of the 55mph difference
CAI= 90F checked for fun on the way home.

I noticed a spike in CAI intake temps when accellerating. To be expected because of the load the engine is under.

I'd assume the temps would be lower if I moved my coolant bottle and laid my PCM flat for the most air to be moved through.

All in all for those that are running an open cone intake (warm air) You'll be much better off just wrapping the filter area with reflectix no cardboard needed to hold shape. Mine has held up fine with out re inforcement so don't be afraid just do it.

Good to know Prof. Herc!

You should be on myth busters.

I love that show.

I can imagine Herc in the belly of his plane with the roll of toilet paper now...

Hello,

139* in your intake??????
You know your PCM starts pulling timing at 104*.
I was at the track last Saturday, and plugged in the scanner. I noticed my IAT was about 108* while it was only about 70* outside. This was due to me hot lapping, and not opening my hood to cool off. I immediately opened my hood and started the car. The temp dropped down to 102* and wouldn't go any farther. I finally realized that I wasn't going to gain anything if my engine temp went over 180*, so I played with it till I staged...... It was one of my worst runs.... No biggie since I was there to work on my RT, but just trying to emphasize how difficult it can be to keep KR down by keep everything cooler.
Dang I miss my fan switch.

Later now,
Clint

Sounds like an intercooler in your future?

Hello,

The IC doesn't change the timing changes that the PCM makes according to IAT.
You either need to make your IAT's lower, or spoof the PCM with a resistor if your IAT's are higher then 104*.
The IC cools AFTER the IAT sensor which virtually eliminates KR, but still doesnt' bring back the timing lost from the high IAT.

Later now,
Clint

That makes sense. Thank you for correcting me.

There is no way to move the IAT after the intercooler?

Hello,

Even if this were possible, it would be senseless. The air temp after the IC is still well above the temperature that is coming into the air filter.
The best way to keep the IAT reading at an appropriate level is by spoofing, or putting an extension on. I have an extension, and I still get readings above and beyond what I would prefer if I don't take other measures.

Later now,
Clint

so in regards to the spoof, what company (if any) makes a reputable resistor to plug into the IAT sensor and spoof it. also will it hurt the engine to have one of these things plugged in all the time, or will it have no adverse effect?

The 139 I saw was at idle with no vehicle movement. The reason I believe it was so high is because the fan for engine cooling is on that side of the car and blows the hot air from the radiator to the fire wall. A heat extracting hood would kill alot of that under hood heat.

Hello,

The spoof is mainly for "off road use".
If you use it all the time, you may find yourself in a position to not control other elements, like engine temperature, or extreme intake temperature.
This may cause detonation, and harm your motor.
Even at the track, if you don't pay attention to the other elements, you could create a favorable environment for detonation, so, user beware.
If you decide you want to try to spoof the PCM, you can use any resistor bought at Radio Shack. Here is a list of which resistor will tell the PCM what.....
http://home.comcast.net/~pdxcgp/IAT.htm

Later now,
Clint

Herc teh hottest underhood temp you saw was 139*? im trying to get soem info because in my manufacturing tech class at school im making myself a TB spacer out of Dupont Delrin Plastic, and i wated to know teh underhood temp so it dosent melt when teh car runs.

P.S. sorry to bring back a dead thread, i just wanted to know

right, but at least a few spots on the TB spacer will constantly be in contact with the coolant, which is usually between 165 - 210. Where the coolant gets to the TB it might be a little cooler, but you dont want to forget that stock, the throttle body does see coolant

Hello,

Does anyone know how hot the SC gets?
I don't think it gets as hot as the engine, but I may be wrong.
If you are attempting to build a spacer out of plastic, I would think you would be concerned about the max temp of the SC itself.

All I know is that the supercharger stays hotter for a lot longer than the rest of the engine, like the heads.

The underhood temp was over 158 at idle. You can block off the coolant passage to the TB to help lower air intake temps. Be ware in colder enviroments you may experience engine stutter.