Intake air temperature measurement

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Ole
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Joined: Thu Sep 06, 2018 12:51 pm
Location: Norway

Intake air temperature measurement

Post by Ole »

Did a quick test today measuring the intake air temperature with and without the oilbath air cleaner. Outside temperature was just above freezing at 2-3 celcius. Drove at normal road speeds (approx 60kph) while measuring. The probe was placed where the outside air is taken from not inside the intake manifold.

With the stock setup, dry airfilter+oil-bath airfilter, air is taken from right behind the cooling fan. The intake air was about 5 celcius above the outside air.

With the oil-bath filter removed running only the dry filter the air is taken from furter inside the motor compartment right above the left cylinder. The intake air in this case was 20+ celcius above the outside air.

Seems like it would be smart to run a tube from the airbox to a colder place if removing the oil-bath aircleaner. If the intake air is 20 celcius above ambient on a hot day I imagine the motor will seem low on power.
Last edited by Ole on Fri Dec 14, 2018 9:46 pm, edited 1 time in total.
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heinkeljb
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Re: Intake air temperature measurement

Post by heinkeljb »

There are at least three different air intake systems:-

The oil bath has a straight pipe the opens just under the top engine lid.
The oil bath has a cyclon air intake attached to it in the engine bay, therefore air intake is down near the oil filter.
The oil bath has a long pipe going to the front of the vehicle to a cyclon air filter afixed to either the very front or the side depending on the model.

So air intake temperature will vary depending on which system you have.

John
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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Ole
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Re: Intake air temperature measurement

Post by Ole »

Good point John. I removed the cyclone part of my post as I only have the oil bath filter.

I guess the system that takes air from the front bumper will have the coolest air coming into the engine.
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AustHaflinger
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Re: Intake air temperature measurement

Post by AustHaflinger »

Ole wrote:Seems like it would be smart to run a tube from the airbox to a colder place if removing the oil-bath aircleaner. If the intake air is 20 celcius above ambient on a hot day I imagine the motor will seem low on power.
At them moment (well for the last 4 years) I have not had the oil bath connected nor the front air cyclonic intake and just use the paper air filter.

Your logic on power reducing with temp makes sense however in reality on a haflinger I dont think it happens.

Temperatures where I live range from about -6c in winter (early morning) to about 42c in summer (mid afternoon) and driving my haflinger in both temps I have not really noticed any difference (though it does take a long time to warm up in the cold) - noting in the cold weather air intake temp should be higher as it will help prevent carburettor icing - I used to get it a lot here on cold mornings in my old Subaru with a weber but not had it in the haflinger. Also note that the haflinger is not designed to suck in real cold air like you will have up north and there is the flap in the door to stop cold air going in and the flap on the air outlet to keep hot air in.

See the entry in the Handbook - so clearly the temp in the engine bay needs to be "optimum" (???) lots of air in on hot days and not much on really cold days.

Garry
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Ole
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Re: Intake air temperature measurement

Post by Ole »

Totaly agree with the manual on cooling. But I tink this is more focused on cylinder and oil cooling. If the system is made to handle 40+ celcius it will seriously overcool the oil and cylinders on a cold day if not using the air flaps to restrict the volume of cooling air.

To prevent icing it allready have the heated intake manifold so it should not need hot air coming in on top of this. Maybe you have 0,2hp just waiting to be released by adding a intake pipe to a cold place in the engine Bay:)

Edit: Curious about this I checked up some air density calculators on the web. It seems like lowering the intake air temperature about 20c (everythig else the same) on the Haffie have the potential for about one (1) more hp of output.
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