RE: Warm vs Cool air

["Jorge Mazlumian" <jmazl@domain.elided>]

>Subject: Re: Warm vs Cool air
Franco asked:
>>2- Is there any drawback to drawing in warmer air from the engine bay than
>>cooler air from outside?
Rich wrote:
>Yes.  All of Alfa's 2 liter engines produce different amounts of power
>depending upon the model year, but let's say the the engine in your car
>produces 129 HP at sea level on a standard day (72 degrees F), breathing
>outside air.  Now let's say we reroute the intake plumbing so that it's
>breathing air from the engine compartment, and let's say that the air in
>there is 110 degrees F.  Breathing that air, the engine will make about 114
>HP.  So you can see that it's important for an engine to breathe the
>coolest air that can be found.  Unfortunately, that often means ducting the
>outside air to the engine, making more of a mess in the engine compartment,
>and muffling the intake noise at the same time.
>
and Simon wrote:

>The hot vs. cold issue is simple thermodynamics. An engine that breathes
>cool air will produce more HP than the same engine breathing hot air.
>This was the source of Fred's somewhat harsh comments that anybody who
>tosses the stock air box for a "high performance" filter is kidding
>themselves. If you get a high performance filter that goes INSIDE the
>stock air box, you may get a slight improvement in power with better
>filtration. I happen to like K&N filters.

It's no secret: cold air has more oxygen per volume unit
than hot *expanded* air.

Jorge
Milano, (working out something to bring in more cool air, may be a liquid
oxygen tank :))

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