Intercooler Upgrade

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

I was driving along the Eyre Highway one night many, many years ago. I had the Cortina sitting on @140. The engine temp was right the way down into the cold. I too was cold and had a sleeping bag wrapped around my legs. After a while the engine started surging. I pulled over, got out and went to open the bonnet. The leading edge was covered in ice. On lifting the bonnet I found the dual twin barrel Webers were completely encapsulated in ice. No wonder the engine was struggling. My point? Too cold and the fuel won't atomise. Liquid fuel doesn't burn. Cold dense air has more O2 molecules but you still need the fuel to atomise for proper combustion. You can't make the ambient air colder simply by pushing it through an inter-cooler unless you put the cooler inside a refridgerated compartment. A mate runs a supercharged LPG powered Windsor V8 in his cobra. He has water injection to cool the impellors and this in turn slightly cools the air charge to around 30 - 50 degrees higher than ambient.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Diesel is a different kettle of vertebrates. You couldn't cool the air enough to prevent combustion in a diesel. Cool air is dense air.

[wholesalesuspension Advanced Member Find all posts View Profile Close wholesalesuspension]

Hi Jason,

Interesting topic.

Not sure of the actual location of the Intake air sensor but the difference on highway is so consistent that I just subtract 2 to get the ambient air temp as shown on instrument panel. In the harder conditions I have seen 65C or more for intake.

The 150 front mount intercooler is full width and full height. A lot bigger than the top mount in my old 95. It is mounted between the water radiator and the Aircon condensor though.

Are you talking diesel or petrol turbo engines?

I had not thought much about any differences between the two. Yesterday I was in another car, petrol with frontmounted intercooler and was surprised how high the temps were. Going up hill, steep with lots of boost intake temp was about 45C, ambient about 20C, At crest of hill intake temp dropped to 38C or so. Then long down hill temp went up again into the 40's with no boost and full vacuum, strange I thought. Then level roadwith a bit of throttle, intake temps plummeted, well sort of down to 31C.

Then I thought about it what was happening. A petrol engine has a throttle valve, this controls the amount of air flowing through the intake. A Diesel normally does not and has virtually no restriction on airflow (hence no vacuum for power brakes). In the above example the temperature was also being affected by the amount of air flowing through the intake system. More airflow temps lower, less air flow temps higher. I suspect with lower volumes of air heat soak into the air from turbo and other engine bay components will have a greater effect.

Cheers
Prone

Our vehicles have a throttle valve too. All have since fly by wire was introduced on my 95 Series.

The one's i have data logged through work are all Diesels.
Some air to air & some water to air.

I have seen some good water to air intercooler systems at work on vehicles towing heavy (3T) caravans where intake temps are approx 10C above ambient on big hills. Very efficient.

Have also seen some Dry Ice systems on drag stuff get intake temps of -2C to -4C Pretty impressive stuff.

Regards, Jason.