Air Inlet Temps

[tilly]

Here is one for the gurus,
Ok have loaded air intake temp on the scan guage but what does it do and what do the temps mean to the average user.
Is there a danger limit on the temp.
Thanks in advance

[aaron.miller]

I guess its showing you how effective your intercooler is. The cooler the air is the denser it is, the more energy produced at combustion.

Out of interest what temps are you getting?

Aaron

[old Jack]

Hi Tilly, I do not have the answer but there are 2 inlet air temperature sensors on the Challenger.

One is built into the MAF sensor on top of the air-box and it measures under bonnet inlet air temp pre turbo, pre intercooler, etc so it is ambient + additional heat from engine bay.

The second temp sensor is on the induction manifold and this measures the actual intake air in the manifold just prior to induction into the cylinders so obviously this will be higher than the MAF sensor temps as the air is boosted and the intake manifold will be quite hot .

I am not sure which temp is measured by the Scangauge, I will take a closer look to see if I can confirm though.

EDIT: A quick check of the Scangauge User Manual Pg 27 states that CIA (Celsius Inlet Air temp) should be "slightly higher than ambient due to under bonnet temperatures", it is easy for under bonnet temps to reach 70, 80, 90 and even 100 degrees Celsius on a hot day when the engine is working hard and one must remember that most of the air that comes into the engine bay has passed through the radiator, intercooler, transmission cooler and AC condenser first plus the additional heat input from the turbo and exhaust systems.
So based on this I am thinking the air temp sensor in the MAF sensor is used by the Scangauge.

cheers, old Jack.

[NFT5]

Isn't the standard air intake on the Challenger mounted on the top radiator support panel so it draws almost directly from the outside, under the front lip of the bonnet?

It will heat up a little as it passes through the intake tube to the air filter box, but doesn't take quite the circuitous route that you describe. If the vehicle has a snorkel there will be even less preheating. I'd expect a couple of degrees over ambient to be pretty close at the MAF sensor.

[Drjohn11]

I guess its showing you how effective your intercooler is. The cooler the air is the denser it is, the more energy produced at combustion.

Out of interest what temps are you getting?

Aaron

In a recent trip to King Ash Bay in the Northern Territory last month outside temps on the road were 35-42 degrees Celsius and on my scan gauge air intake temps got up to 65 degrees Celsius. Was towing a 1200 kg boat and normal water temps were 90-94 degrees touring at 100- 110 km/hr Up hills the temp climbed to the upper limits stated. . The Automatic Transmission temps varied between 70 - 100 degrees with again the higher reading being reached with uphill climbs . Total average diesel consumption for the 7500 km trip was 17L/100km. most of the trip was high speed highway driving towing the boat.

Alex

[Griff76]

Interesting thread.

I have recently installed a blue tooth transmitter and hooked it up to the Torque app. on my phone. Quite a cheap method really. I can only assume the figures displayed on the app are correct. After all, the blue tooth reader and app are only visualising the information output by the OBDII

According to the Torque App, inlet temps on my Challenger have reached 60 C. while the "coolant temp" has reached 97 C. This for only short periods but I would have thought that it was quite high. Usually while only towing a 6x4 with a smallish load or similar, and then up a hill. However given boiling point is approx 100 C. it is a worrying figure.

I assume boiling point is higher when you add coolant and put it under pressure in a closed system. I don't like watching the figures go that high though.

The average highway running temperature of my coolant according to the app is 93-94 C. It climbs quickly when engine load and boost pressure rise.

This on day with an ambient temp of 20 C.

I would be very interested to see what temps you guys are getting. Should I be worried?

[old Jack]

Interesting thread.

I have recently installed a blue tooth transmitter and hooked it up to the Torque app. on my phone. Quite a cheap method really. I can only assume the figures displayed on the app are correct. After all, the blue tooth reader and app are only visualising the information output by the OBDII

According to the Torque App, inlet temps on my Challenger have reached 60 C. while the "coolant temp" has reached 97 C. This for only short periods but I would have thought that it was quite high. Usually while only towing a 6x4 with a smallish load or similar, and then up a hill. However given boiling point is approx 100 C. it is a worrying figure.

The Challenger has a thermostat that starts to open at 82C and is full open at 95C and as diesels run hotter than petrol engines the 97C is ok, this is what mine sits on most of the time and the gauge is at 1/2. The cooling system runs a 30/60 ratio coolant and a 94-122kpa pressure so this brings the coolant boiling point up to 119-124C so I would not be getting worried until about 112-115C.

I assume boiling point is higher when you add coolant and put it under pressure in a closed system. I don't like watching the figures go that high though.
Knowing the above info hopefully you can relax.

The average highway running temperature of my coolant according to the app is 93-94 C. It climbs quickly when engine load and boost pressure rise.
I find it is the slow city traffic in summer that push the coolant temps up a little.

This on day with an ambient temp of 20 C.

I would be very interested to see what temps you guys are getting. Should I be worried?

This afternoon I took particular notice of my inlet air temps, around the city in 20C outside I was reading 50-55C inlet in the traffic, highest I can remember seeing is on a 45C+ day last summer on a very long & steep hill climb at 110kph, fully loaded (not towing) and that was about 70C inlet air temp and I seem to recall about 106C coolant temp and 75-80C ATF.



cheers, old Jack

[Griff76]

Thanks OJ. Great information. I had hoped that I was worrying needlessly.