Intercooler able to cool intake air to ambient temp?

[browny]

Roy, that was going to be my next suggestion. Try putting both the ambient and charge air sensors on a piece of ice. Obviously both should read 0deg.

[R31_IceMan]

okay the temp sensor is in the right spot. its on the intake pipe with the temp sensor inside the pipe. a wolf will not work unless it has this reading. and i though it was shit but lets just say that after 10min of pushing 21psi the car was still reading bellow ambient temp. it is possibile. how does a fridge work. the gasses are compressed and the alowed to expand. the piping from turbo to cooler is 2" and the piping after is 3".

i talked to my dad about it the first time i saw the reading cause i though it was impossibile but at the next vic cruise he should be there and you can get in the passanger seat and read it stright off the wolf hand set or of a computer what ever you choose but it does work.

Roy i don't have to do that cause the wolf engineer couldn't comprehend what he was seen but after 2 temp sensors and the wolf programer sayinng that the results were right he has a car that is tuned and is pussing the 290rwkw.

i don't care i have done physics and i do know that it is not impossibile but it is hard to do and sadly he is one of the guys that has got it to work so he will always kick my arse in a drag on a hot day.

[Roy]

Sorry, since you have done physics maybe you can tell me how.

You cant use the example of a fridge, they use gases known as refrigerants (what type i dont know... it may be R22) and use condensers and evaporators to do what you are claiming is possible.

Im not doubting what you say is true, its the explanation that the intercooler is responsible for the inlet temp is what im having trouble with.

I work in the engineering field and have had experience with heat exchangers used in naval vessels, power generation, air conditioning etc. I cant see that its possible.

Does the air temp readings make sense when you look at how the car is beind driven.

You've got me hooked now, what fuel is he using.

[Roy]

Actually im guessing the computer is interpreting the voltage signal from the air temp sensor wrong. What type is it, Delco?

The car will still run great as its being tuned off a lambda up its exhaust, and will be tuned to a signal (whatever its range) from the air temp sensor for air temp compensation.

Now the handset is telling you 4 degrees, great i dont doubt thats what its saying. But the calc its doing to convert voltage to temp isnt right.

Id go as far as to say that the ECU is out by a factor of 10, either by x10 in code or resistor used somewhere. When its reading 4 its actually 40degrees.

[browny]

You are correct - gases do get cooler when they expand. Refrigerants are really just gases that have desirable condensing/evaporating temperatures/pressures.

I find it very unlikely that you would ever experience this sort of effect.

[browny]

or Roy, maybe the reading is a relative temp, ie intake temp is 4 deg above ambient. That would make more sense on a day where the temp was 28deg and the reading was 18.

[Roy]

Refrigerants are really just gases that have desirable condensing/evaporating temperatures/pressures.

Arent they techniclly referred to as a fluid, as they often undergo phase change during the heat transfer process?

[Roy]

browny, yeh that actually makes even more sense.

Id still have a leaning towards the conversion from voltage to air temp is out, as i would think it unusual that they display inlet air temp in this manner.

During the tuning you would have to factor in what the inlet temp is displaying over the ambient temp. If it reads relative, you would then have to tell the ECU relatice to what

Wouldnt this make it more difficult to actually use the reading for air temp compensation?

Im hooked i need to know why the handset is reading the way it is:D

[R31_IceMan]

Guy sadly i'm going on holidays for 3 weeks and wont have the net. look roy i'll be back and when i do so i'll get you a meeting with Ryan the guy with this cooler and amazing car.

i've PMed his number to you call him and find out for yourself.

cheers Dave

[Roy]

Guy sadly i'm going on holidays for 3 weeks

Sadly, hell holidays are good, i could only screw 2 weeks out of my bosses.

Im in Syd, so cant really ever see the car, but would still like to know more about the car. Cheers and have a good holiday:D

[MLCrisis]

Hi guys. Another engineer - couldn't help but chip in. For any heat exchanger (i.e. intercooler) to cool incoming gas to the same temperature as the coolant (i.e. ambient air) would require an infinite surface area. The most efficient heat exchangers, using fluids with good heat transfer charateristics (i.e. liquids, not gases), will at best give you an approach temperature between the two streams of 5 degrees C. Gas to gas heat exchangers are much less efficient, because the heat transfer coefficient from the gas to the metal and then metal to the gas is very low, even with turbulent flow on both sides of the metal. Expansion of a gas will give you some cooling effect as well. Going from 2" to 3" pipe more than doubles the cross sectional area of the pipe, so it is a significant expansion. But the temperature drop due to such an expansion I would doubt would be significant. Anyone fancy doing PV=nRT calcs, while allowing for compressibility?

Such fun.

[Ronin 09]

Just what we need... another engineer

I will pass on the calcs - actually when i get time tomorrow i will do it.

[PuppaDuck]

I also know a guy who has retested a situation where he was pulling negative temperature differences...I don't know how much of a difference (I assume it wasn't anything significant) but he is very thorough and swears to it.

He's the type of person who would do nothing else in his workshop for a week until he has resolved something.

I remember he mentioned the type/size/quality of the FMIC core had a lot to do with it.

[Cubes]

If a R33 or R32 turbo is on the edge of its efficiency it will be basically impossible to reduce the intake temps to ambient as the air will be so damn hot.

[kjb_r33]

I had a turbo 4 banger on a dyno, stock (small) intercooler. Ambient temperature of around 20 degres, intake temp pushing 70 degrees.... at a mere 8PSI.

[Sydneykid]

Hi R31_IceMan, all of us experienced in this field say it is impossible. So I would say there is a problem with the measurement, either the positioning of the sensors or their calibration.

Simply put you have one temperature gauge/sensor reading the ambient temperature and another temperature gauge/sensor reading the inlet air temperature. The answer would be to swap them over and then see what sort of readings you get.

My money is on calibration error.

[Ronin 09]

Was wondering when you'd get one in, Sydneykid

[blind_elk]

An air-air intercooler cannot possibly reduce the charge air temp below ambient. Otherwise the charge air would start drawing heat from the ambient air because it is at a lower temp - simple thermodynamics.

So the absolute best you could expect the IC to achieve is ambient temperature of the charge air.

And because no air-air IC is 100% efficient, that is impossible to achieve.

My 2c (physics and chemistry)

[TTT]

just to add another simple thing..

does this car have a pod filter sitting in the engine bay?

My R32 GTST has an AMB temp button on the dash.

I also bought a little digital temp gauge which has a temp probe.

the temp probe is stuck in to my pod filter.

the pod filter is partitioned off from the engine bay by this foam/heat shield material (not the best but it is ok for now)

when driving at night at about 80km/h, amb temp showing 15 degrees, the partitioned pod filter temp shows 17 degrees (which is damn good)

in stop go traffic, I've seen the temps go to 55 degrees at the filter while it is about 18 outside.

now this is while driving off boost or sort of on and off low boost..

Now, if the air going in my pod filter is say 20 degrees on a 15 degree night, then it goes through the turbo being compressed causing it to heat up some more, how can you expect an intercooler which is simply air to air to reduce this temp to below 15 degrees?

I will be getting another of these digital temp gauge/probes to put in just before the throttle butterfly so I can see how efficient my intercooler is and also to see what temps are entering the engine.

I will add another post when this is done to let you all know.

by the way, the temp gauge I bought is good from -30 to +150 degrees.

I tested it with a normal chemist thermometer in a glass of water and it was identical.

[Mini Me]

how does the air temp get acuratly measured when it is moving at a certain velocity?