today i was given this digital Compass/Thermometer thing from my dad he picked it up at a yard sale this morning brand new.

http://www.atcomp.com/php/product.ph...t=6&prod_id=14

at first i didn't think much of it, then i realized i could probably install it in my intake to monitor heat soak this summer. so i went out to my car and pulled the DIN pocket out and grabbed the dremel. i'll get around to wiring it in and installing it alittle later today.

S4 N/a motor with stock intake box

so the one question i have is : where along the intake should i install the sensor? before or after the filter?

 

I can't see that the filter would have any impact on the intake temp (unless you have the very rare, highly desirable Weapon Type R Water Cooled Air Filter Kit Yo) so I'd put wherever was most convenient.

 

any other input please

 

put it as close to the TB as possible. that way its as close to the engine as possible. so that would get the most heat right?

so i say, as close to the engine as possible.

haha i said a lot of, "as possible"

 

Yes as close to the TB as possible. It would be the most accurate temp that your engine is getting.

 

okey i got it all installed this morning, it's 72' F here this morning, after about a 30 of driving hard intake temperatures rose to 94' F and stayed there,

i currently am using a complete stock intake setup. i'll run this setup for another month or so while i start working pn a couple different CAI setups i'd like to try out

stay tuned i'll keep this updated every week or so

 

wow heat soak is horrible once you've driven around for a bit then turn the car off. with no fans or movement to push the heat out, intake temps start climbing to alittle over 120'F from the residual engine heat.

could that be a part of some peoples hot start problems??
how badly do you think that hurts mileage?

 

The temperature gauge will pick up a false high reading from the metal manifold or plumbing if you do not isolate the sensor.

 

it's installed in the large rubber intake pipe the about 6" in front of the TB

 

The intake temp readings are too high for a stock NA system. Somehow the thermometer is picking up the radiant heat from the engine bay.

 

it's gotta be the heat within the intake pipe though because the entire sensor is inside the intake piping.

once you turn the engine off and theres no airflow the heat soak kicks in, and the temp starts climbing. the temperatures stay over 100' for well over an hour after driving the car.


aslong as the motor is running the temps stay down under 90.

 

It is normal to get some heat soak with the engine off. It is not normal to get a 20F heat transfer with the engine running. Something is wrong.

 

??? can you explain yourself better please? all yoru doing is arguing my point and not explaining why

 

closest to the throttle body that way you can tell how hot the air is, right before it hits all the important stuff (ie. throttle body, injector area, engine) and all that other fun junk thats down there. I mean why would you put it anywhere else, who would give a shiet how hot the air is in front of your stock air box.


Just for the record, even if you could read how hot your intake air is, you wouldnt be able to do anything about it except make a "cold air" box but you cant do that anyway because you have the stock air filter and crap on. so thats my input, good luck

 

I THINK he's suggesting the material the sensor is attached to/bolted to/screwed to, is transferring heat to the sensor which means that the reading of the sensor is not just reading the air temp.

By the way, you'd be surprised how much the stock air intake temp sensors are heat soaked by the material they are attached to. You can see this temp on a RTEK2.0. Ain't pretty. I've read that temp on a RTEK2.0 and compared it to the readings from a digital thermometer (Fluke 52 II with alumel/chromel probe) and have a fairly good clue of what I'm talking about.

 

I wouldnt worry about hte sensor getting heatsoaked, its what the ecu is seeing from the stock iat sensor anyway. like hailers said, the rtek shows about the same temps you are seeing.. usually about 15-25 degrees F above ambient

 

he's been at the physics books again... um how much energy does it take to heat up a MOVING column of air vs cooling down a little sensor?

and if you actually LOOK at the stock intake system its not really a cold air system, its more of a not as hot as the radiator system

 

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Plus I have 19 years of experience with these cars. I don't know if your temperature gauge is bad, or if it has a calibration or position error, or what the problem is, but your indications are not consistent with what I have seen on any FC.

Are you sure you have a stock system with all of the intake components attached? I have seen some used cars that did not have the intake snorkel attached to the air box. Also, is your fan working OK?

All of the commercial "cold air" intakes I have seen are acutally ambient air intakes, which is what the FC has in stock form. The difference is that the stock FC intake scoops in spill air from the high-pressure heat exchanger cavity, while most of the commercial "cold air" intakes are just a filter on the end of a pipe.

 

Tell you what. It's 67 degrees in Ft Worth now. I go for a ride for ten plus miles on the hwy at sixty five mph driving into the north wind. It took every bit of that ten miles of steady driving to get the temperature in front of the afm air temp sensor to drop down to 76 much less 67 degrees.

Get off the hwy and on residential streets. Wheeee. Climbs into the 80's. Drive into the driveway. Yipeee! After a minute we're challanging the 100 degree mark.

The stock snorkel, airbox/filter is a pre-heater. NO worry about icing up the intake and getting ice in the turbo.

 

Does the car have the stock radiator fan, shroud, and the two stock black plastic duct pieces installed by the hood latch?

FYI even my friend's FC with just a cone filter and intake pipe (no air box) still saw close to ambient intake temps once the car exceeced about 30mph.

 

Stock with the exception of a Koyo radiator (runs too cold in the winter). No I don't have the two plastic panels to the right and left of the hood latch. I guess I'll put 'em on someday and test again.

Every other thing is stock from the snorkel to the stock air box with stock airfilter. The Fluke's alumel/chromel probe wire was inserted thru a 1/16" hole I drilled in the top of the airbox....punched a hole thru the filter.....and dangled the wire directly in front of the stock afm air temp probe.

Frankly my cars are odd *****. I can run without the bottom plastic fairing and the two plastic fairings you mention and not even come close to overheating. I credit the Koyo, which in my opinion makes the water temp tooooo cold in the winter/spring/autumm. I need to write a thread *** My car runs too cold, HELP**

 

And your probably right, I'm probably sucking hot air into the snorkel because of the dumped fairings (It's called the Fairing Dump MOD). Worth serveral extra hp plus it will make you more attractive to good looking women.

 

The Mazda engineers put the fairings there for a reason... they want all the good looking women for themselves!

 

my car is complete i have all of that stuff.

i'm not having the same problem as hailers, while driving around the temperatures are like 10 degrees hotter than outside temps , it's when i drive over to my buddies and park for a few minutes and then when i leave i see the temps at 115+ for a few minutes until i get some air moving.

so aslong as you have everything still intact heatsoak isn't a big problem in our cars unless you drive around and make alot of stops,