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RE: Power Output
At 02:53 PM 4/2/98 -0800, you wrote:
>Ok, so am I right that 1.8 bar will still be 1.8 bar no matter what temp
>is due to wastegate control. I know in a tire it would change, that is
>why on a cold day, the press in tire will change when you hit the track,
>but the wastegate will release at 1.8 bar which is always the same, right.
Should stay pretty much constant since it's operating against a mechanical
part.
>I am a little confused as to whether you are agreeing with me,
>disagreeing, or just adding more info.
Basically, I agree with what you said. Perhaps a bit of vocabulary
correction. :-)
>The way I read your info, I was right that the pressure will still be 1.8
>bar but at a higher volume entering the cyl. Am I right?
Not a higher volume but a greater *mass* of air will enter when the
temperature is lower. That's the main function of the intercooler - to
cool the air charge so that it will be more dense and contain more mass of
air in a given volume of air. You have the right idea but are saying it
incorrectly. The volume is fixed at the capacity of the cylinder so you
can't add more volume but by compressing the air (turbo) and cooling the
air (intercooler) you can pack more mass into the fixed volume container.
Yeah. I know. Picky-picky-picky. :-) My chemistry students always
thought very highly of me. They constantly were calling me a "Sweet Old
Boy". Uh, that *is* what those initials stand for, isn't it? :-)
>On Wed, 1 Apr 1998, Robert Myers wrote:
>
>> Todd,
>>
>> The basic equation is PV = nRT.
>>
>> n = mass/molewt, so PV = mass*R*t/Molewt
>>
>> Density = mass/volume = P*molewt/RT
>>
>> The volume of the cylinder (within limits) is fixed. The molewt is fixed.
>> R is a constant. Therefore the only independent variables are P and T.
>> What we want is greater mass of air which allows burning a greater amount
>> of fuel which produces more power. The equation shows the higher pressure
>> and lower temperature favor this condition.
>>
>> At 05:55 PM 4/1/98 -0800, you wrote:
>> >
>> >1.8 Bar is 1.8 bar no matter what the temp. At higher temps, the turbo
>> >has to work harder to get 1.8 bar because the barometric pressure of the
>> >outside air is lower.
>> >
>> >I guess the old anology, "which is lighter, one pound of feathers or one
>> >pound of lead". Well, neither, they are both one pound. But the pound
>> >of feathers will take up WAY more space.
>> >
>> >That make sense? I am not the say all, know all, so I may be off a little
>> >on this but if my Flight lessens taught me anything about the way air
>> >works, I should be right.
>> >
>> >I think that the volume of air might be different though. Hence, people
>> >use intercoolers to force more air in. Cools the air, makes it more
>> >dense, so more enters engine but at same pressure. That might be the
>> >power difference you are feeling. I know airplanes have huge differences
>> >in top speed and climb rate at higher temperatures. Cool mornings or
>> >winter is the best time to fly an underpowered plane. Much smotter to
>> >BTW.
>> >
>> > Anyhow, hope that was of help. L8R
>>
>> ___
>> Bob
>> *****************************************************************
>> * Robert L. Myers rmyers@inetone.net Home 304-574-2372 *
>> * Rt. 1, Box 57 FAX/Modem 304-574-1166 *
>> * Fayetteville, WV 25840 USA WV tag Q SHIP 2.2+ bar *
>> * Obligatory quattro and sleddog-L references: *
>> * My 3 Siberian Huskies enjoy riding in my '89 200TQ *
>> *****************************************************************
>>
>
>
>
>
___
Bob
*****************************************************************
* Robert L. Myers rmyers@inetone.net Home 304-574-2372 *
* Rt. 1, Box 57 FAX/Modem 304-574-1166 *
* Fayetteville, WV 25840 USA WV tag Q SHIP 2.2+ bar *
* Obligatory quattro and sleddog-L references: *
* My 3 Siberian Huskies enjoy riding in my '89 200TQ *
*****************************************************************