Air intake mixture question
Joined: Sep 2006
Posts: 25
RE: Air intake mixture question
There are a few other things to consider when thinking about a intake and how it may help your performance.
1. It doesn't necessarily mean that there's more air entering the engine. It does mean there is an increased capacity for airflow into the engine.
2. The cooler charge helps. It allows you to pack more air in a smaller space. However it does also help see next
3. Pumping work during compression. Any one here had a thermo class? Do a isentropic compression, ideal gas with first with a hot gas, then with a cool... you'll notice a higher delta temperature on the cooler initial charge than the warmer.. We all remember delta temperature = work (usually the wasted kind).. So less pumping loss = greater mechanical efficiency.
4. Another area of pumping work.... That is lower pressure differential across the intake system, lower pressure in the intake manifold = lower intake charge density.. Pumping work is = density * dv/dt... so less pumping work again.
5. Cooler intake charge puts temperature after isentropic compression further away from auto-ignition temperature, so the engine will be less prone to knock. Knock will kill performance, it will also keep you from optimizing cylinder pressure reliably. On top of that the cooling you will have to do to make up for the cooler intake charge will likely have to be done with some latent heat of formations or evaporations with extra reactants.. IE waste fuel to cool intake charge.
Number 5 really doesn't pertain to much in this type of application but it is very real and has to be dealt with especially in a forced induction engine.
I recommend anyone who can stand it to use a plastic cold air intake.. Not only for performance but for gas mileage.
1. It doesn't necessarily mean that there's more air entering the engine. It does mean there is an increased capacity for airflow into the engine.
2. The cooler charge helps. It allows you to pack more air in a smaller space. However it does also help see next
3. Pumping work during compression. Any one here had a thermo class? Do a isentropic compression, ideal gas with first with a hot gas, then with a cool... you'll notice a higher delta temperature on the cooler initial charge than the warmer.. We all remember delta temperature = work (usually the wasted kind).. So less pumping loss = greater mechanical efficiency.
4. Another area of pumping work.... That is lower pressure differential across the intake system, lower pressure in the intake manifold = lower intake charge density.. Pumping work is = density * dv/dt... so less pumping work again.
5. Cooler intake charge puts temperature after isentropic compression further away from auto-ignition temperature, so the engine will be less prone to knock. Knock will kill performance, it will also keep you from optimizing cylinder pressure reliably. On top of that the cooling you will have to do to make up for the cooler intake charge will likely have to be done with some latent heat of formations or evaporations with extra reactants.. IE waste fuel to cool intake charge.
Number 5 really doesn't pertain to much in this type of application but it is very real and has to be dealt with especially in a forced induction engine.
I recommend anyone who can stand it to use a plastic cold air intake.. Not only for performance but for gas mileage.
Joined: Apr 2006
Posts: 7,253
From:
RE: Air intake mixture question
I have the plastic CAI on my h3 and have always used plastic but I have a question regarding that. My brother is looking for a CAI for his new Jeep, the only thing available right now is a CAI made by brute (something like that) anyway it is ceramic coated aluminum. My brother called the company to see if they have a plastic one and the tech support guy he spoke with said that the ceramic coated aluminum actually keeps the air cooler than a pvc plastic one. Is there any truth to this?
Joined: Apr 2006
Posts: 7,253
From:
RE: Air intake mixture question
oops, my bad...It's powder coated aluminum, not ceramic coated. I went to edit my post but you beat me to it
I can kinda see how it may disapate heat because if you put aluminum foil in the oven it doesn't really get all that hot. I still can't see how it's better than plastic...but I'm not sure either
I can kinda see how it may disapate heat because if you put aluminum foil in the oven it doesn't really get all that hot. I still can't see how it's better than plastic...but I'm not sure either
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Super Moderator
Joined: Jul 2006
Posts: 6,692
From:
RE: Air intake mixture question
ORIGINAL: Alvin@pcmforless.com
There are a few other things to consider when thinking about a intake and how it may help your performance.
1. It doesn't necessarily mean that there's more air entering the engine. It does mean there is an increased capacity for airflow into the engine.
2. The cooler charge helps. It allows you to pack more air in a smaller space. However it does also help see next
3. Pumping work during compression. Any one here had a thermo class? Do a isentropic compression, ideal gas with first with a hot gas, then with a cool... you'll notice a higher delta temperature on the cooler initial charge than the warmer.. We all remember delta temperature = work (usually the wasted kind).. So less pumping loss = greater mechanical efficiency.
4. Another area of pumping work.... That is lower pressure differential across the intake system, lower pressure in the intake manifold = lower intake charge density.. Pumping work is = density * dv/dt... so less pumping work again.
5. Cooler intake charge puts temperature after isentropic compression further away from auto-ignition temperature, so the engine will be less prone to knock. Knock will kill performance, it will also keep you from optimizing cylinder pressure reliably. On top of that the cooling you will have to do to make up for the cooler intake charge will likely have to be done with some latent heat of formations or evaporations with extra reactants.. IE waste fuel to cool intake charge.
Number 5 really doesn't pertain to much in this type of application but it is very real and has to be dealt with especially in a forced induction engine.
I recommend anyone who can stand it to use a plastic cold air intake.. Not only for performance but for gas mileage.
There are a few other things to consider when thinking about a intake and how it may help your performance.
1. It doesn't necessarily mean that there's more air entering the engine. It does mean there is an increased capacity for airflow into the engine.
2. The cooler charge helps. It allows you to pack more air in a smaller space. However it does also help see next
3. Pumping work during compression. Any one here had a thermo class? Do a isentropic compression, ideal gas with first with a hot gas, then with a cool... you'll notice a higher delta temperature on the cooler initial charge than the warmer.. We all remember delta temperature = work (usually the wasted kind).. So less pumping loss = greater mechanical efficiency.
4. Another area of pumping work.... That is lower pressure differential across the intake system, lower pressure in the intake manifold = lower intake charge density.. Pumping work is = density * dv/dt... so less pumping work again.
5. Cooler intake charge puts temperature after isentropic compression further away from auto-ignition temperature, so the engine will be less prone to knock. Knock will kill performance, it will also keep you from optimizing cylinder pressure reliably. On top of that the cooling you will have to do to make up for the cooler intake charge will likely have to be done with some latent heat of formations or evaporations with extra reactants.. IE waste fuel to cool intake charge.
Number 5 really doesn't pertain to much in this type of application but it is very real and has to be dealt with especially in a forced induction engine.
I recommend anyone who can stand it to use a plastic cold air intake.. Not only for performance but for gas mileage.
That being said, I don't understand how the K&N CAI kit plastic heat sheild can possibly stop all of that hot air from getting sucked into that filter. I mean isn't it better to have it suck the cooler air from the dedicated air intake vent in the chasis rather then suck the warmer air from the engine compartment? I looked at that area and it doesnt look like much outside air can get into that area anyway.
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