Re: Cold Vs. Warm Air

From: Peter L Anthony (panthony@pcn.com)
Date: Mon Nov 08 1999 - 19:14:19 EST


Wow, now that's what I call a definition!!
 Thanks Jon!

Peter L Anthony
PCN Inc.
Network Engineer

----- Original Message -----
From: Jon Steiger <stei0302@cs.fredonia.edu>
To: <dakota-truck@buffnet.net>
Sent: Monday, November 08, 1999 6:01 PM
Subject: Re: DML: Cold Vs. Warm Air

>
>
> On Mon, 8 Nov 1999, Nate Johnson wrote:
>
> > That's great and all and that's what I told my dad! "Cold air is better
> > for more power." but I need something more than that to convince him! He
> > thinks warm air would be better. I'm looking for a more "technical"
> > answer. WHY, is it better for more power?
> >
>
> Basically, its all based on density... Superchargers, turbochargers,
> nitrous oxide, ram-air, cold air intakes, cool cans, etc. are all doing
> the exact same thing, if you stop and think about it. They all give you
> (varying degrees of) more power by increasing the density of the oxygen
> in the engine.
>
> Consider the "stoich" A/F ratio of 14:1. This is what the computer
> in your truck is trying to maintain; 14 parts of air to 1 part fuel.
> My understanding is that if you can shove 14 more molecules of oxygen
> into the engine, then you can burn 1 more molecule of fuel. Since
> you now have one more "explosion" (or chemical reaction, whatever) than
> before, you're also making more power than before.
>
> (I'm sure the physicists and chemists amoung us will shudder when
> they hear that description; but its the best I can do; I am neither
> a physisist nor a chemist.) :-( (If I'm wrong, please correct me.)
>
> I don't think your Dad will argue that a supercharger or turbocharger
> doesn't increase power. What they do is to compress the oxygen, and
> shove it into the engine. This means that you have more oxygen molecules
> per square inch, and for every extra 14 oxygen molecules, you get to
> burn 1 more fuel molecule than before.
>
> Nitrous oxide is similar except that rather than compressing oxygen
> and putting it into the engine, it replaces normal air molecules with
> nitrous oxide molecules, which contain more oxygen. So you're incresing
> the oxygen density there too. (Not only that, but the extreme cold of
> nitrous oxide decreases the temperature of the incoming air by about
> 60-70 degrees.)
>
> Cold air is more dense than warm air. The warmer the air, the
> more the molecules move, and the more space they take up, which means
> there is more distance between each oxygen molecule. So, the cooler
> the air, the more densly packed the oxygen molecules are; you have more
> oxygen per volume than warmer air. That means you can fit more oxygen
> molecules into the engine, and therefore you can burn more fuel molecules,
> and make more power.
>
> According to Nitrous Oxide Systems, a 10 degree (F) reduction in
> temperature is good for a 1% power increase. So, for the Dak's stock
> 220-230hp V8, every ten degrees you can drop the air temperature will
> net you an additional 2.2-2.3hp. I don't think it'd be too crazy to
> say that you could drop the temperature by 40 degrees, in which case
> you'd be looking at 8-9 "free" horsepower.
>
>
> -Jon-
>
> .--- stei0302@cs.fredonia.edu ----------------------------------------.
> | Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
> | '96 Dodge Dakota V8, '96 Suzuki Intruder 1400, '96 Kolb FireFly 447 |
> `--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
>



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