Answer the question, does a set amount of air relate to a certain power rating?

Does a set unit of air in an engine directly correspond to a power value..


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Gt40881j

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So a friend and me got into an arguement about this, I'm going to keep all bias out of it and just let you all answer it and explain your response.

The question is;

Does a set unit of air in an engine directly correspond to a power value. i.e, will 1 liter of air regardless of what engine, produce the same power.

Please explain ,if you can, your answer.
 

suprarx7nut

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The answer to your question as stated is "no".

For air to make power you need a few things.

*Fuel Ratio
*Spark
*Compression
*Timing

If any of the above change, your power will also be affected. Some engines have more compression. In general, that will produce more power per incoming air unit, but only if the rest of the equation is adjusted accordingly. Same goes for timing, fuel ratio, etc... Adding more air without adjusting fuel will ruin a motor quickly. You may gain a little more power if you're using a factory tune with factory equipment, but it's a long string of "ifs".


To give you a full answer would essentially be to give an overview of all that goes into an Internal Combustion Engine (ICE), but I think the above at least gives you an answer to your question.
 

Nick M

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The answer to your question as stated is "no".

For air to make power you need a few things.

*Fuel Ratio
*Spark
*Compression
*Timing
Well stated. What matters is how well the heat can be pulled from the fuel.
 

Gt40881j

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I'll wait a bit before responding so that this remains unbiased, but that's for responding. Keep em comming!
 

3p141592654

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There is a maximum amount of energy you could get using 1 L of air and the correct amount of fuel, so there is an upper bound. There is no lower bound. With no fuel added you would get 0 Joules of energy out of 1 L of air.
 

IJ.

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There is a maximum amount of energy you could get using 1 L of air and the correct amount of fuel, so there is an upper bound. There is no lower bound. With no fuel added you would get 0 Joules of energy out of 1 L of air.
x2, you can use a best possible output calculation based on the fuel burnt and the AFR but it's not going to be terribly accurate, having said that there are so many variables involved you're never going to get an answer to the question as presented.

They use this to calculate Top Fuel engine output as there's no real world way of dyno testing them..
 

Rollus

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Not an answer but a related question:

Some cars, like Huyndai Coupé, have a Torque gauge on the dashboard.

How could this work?
 

IJ.

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Not an answer but a related question:

Some cars, like Huyndai Coupé, have a Torque gauge on the dashboard.

How could this work?
You can run a strain gauge on the Input shaft, not sure how Hyundai do it though probably a calculated torque, I can do this with EFI-Live in my LS
 

suprarx7nut

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You can run a strain gauge on the Input shaft, not sure how Hyundai do it though probably a calculated torque, I can do this with EFI-Live in my LS
I'm willing to bet it's simply a calculated estimate based on engine parameters. Similar to the age old BMW MPG calculation on their dashboard.
 

Gt40881j

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Thanks for the input. I agree and don't know how anyone who understands engines could disagree. There is a maximum potential energy for a unit of air, but no engine runs at 100% efficiency, if you can have two differant values for power with the same volume of air than this theory is proven wrong. For instance just by changing the ignition timing on an engine can alter its power with nothing else changed. Raising or lowering compression would do this as well.

I just wanted a unbiased response to make sure I wasn't crazy because it's two on one and even though two wrongs don't make a right, it's difficult when you have two people arguing against you and they have eachother to lean on. Thanks again lol
 

Grandavi

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The adverse point is that too much air can decrease volume for fuel. That's the only way I can think of for air affecting power. However, if your talking air by itself, then it has no effect. Although, I can't see you asking this as a "air only" because in real world applications the only way power provides energy is if compressed.

Of course, the air ratio is actually critical for power. Too much will result in reduced power as will too little. It's why the ECU monitors aurflow in combustion engines.