Thank you. The way it reads in your first post one might think you were talking about #1.

And since we're in the real world, #3 is the one we're most concerned with.

 

LOL! It's hard to answer the original question without setting the stage with the following techno-babble. And then I drift!

 

what it all comes down to is simple, check to see what it does by getting out of the truck after driving it around, hop out front with the hood up and touch the tank ends of the CAC, you will feal the diff, pass side warm to hot, drivers side cool, and not just a few degrees cooler.

 

All this technogarbel trying to say the same thing. In layman's terms the pin wheel on the compressor beats the air molecules into submission causing a lot of heat. The pressure increase also adds to the heat. Hot air is less dense. The denser the air charge the more efficient the engine. And I thought talking to nuclear engineers was hard.

 

also,
cooling that charged air will drop the pressure of that air. so adding an intercooler to a non-IC truck without any other changes will possibly (possibly as i have never tried it) lower the power. even though the temp is lower and the air is more dense, the pressure is lower and the AFC will take longer, if at all, to add max fuel to the motor (provided it is functioning at the stock level). also, the lower temperature and lower pressure both contribute to a lower efficiency of the thermodynamic cycle during the combustion process.

just another thought im throwing in...

***edit: i put my foot in my mouth early. p*V=m*R*T still applies, but in your example you changed the volume, not just increased pressure. so 'V' is getting smaller and as a result 'p' is increasing. but it took energy to do that and therefore the 100 btu's would increase, not from temperature but from the pressure (dependent on the volume) and change in volume.

either way, intercoolers cool the incoming air to allow us to cram more of it in the combustion chamber and allow us to add more fuel.

 

The lower pressure from an intercooler will not hurt power. Even though the pressure is lower, you are getting more air mass into the engine.

 

pgilles, your disclaimer was right! There is a big power increase when adding an intercooler to a non-intercooled Cummins engine.

 

you're thinking about cooling air in a static closed system.
lets back up a minute and consider the whole system.... the air pressure from turbo to intake manifold is esentially the same (neglecting the small friction pressure drop caused by air flowing through hoses, tubing, and intercooler). therefore the compressed air is cooled, density increases, and pressure remains constant.

 

Wannadiesel is exactly right.....It don't matter what pressure of boost we have. All we wont is mass air flow through the cylinders. Don't get me wrong if we can up the pressure and still keep the air cool, we will have more power, providing we have the fuel to burn. A lot of people think that getting boost high, means big power. But if the boost is too hot, it takes up way too much volume, as well as raises our EGT's.

Think of it this way. You got a non-ic engine making 40 PSI of boost with a stock turbo. So when the intake valve is opened you got 40 PSI pressure forcing air into the cylinder.

On a engine with a added IC we could prolly make the same amont of power with 35 PSI (not exact). Now even though we have less pressure forcing the air into the intake valve, we have denser air which means more molecules per cubic foot. This means we will get the same amount of air molecules into the cylinder using a lower drive pressure (boost).

When i added my IC to my non-in engine i did lose boost pressure. I lost boost because when the turbo is spooled up with the added IC, you get more mass flow through the motor due to the cooler air. When the IC wasn't there the extra boost was because the intake valves couldn't flow enough air molecules to keep the boost down because the air took up to much volume. This is when the air starts to get hot. So by adding a IC you do lose boost. But depending on you boost and turbo efficiency range you could gain power (providing you have extra fuel to burn). On a stock non-ic engine you will not gain any power by adding a IC because your turbo is in it's efficiency range so it will provide cool air anyway. Its when you start making big boost that the IC becomes more beneficial.



Hope that makes sense


Jeff

 

We have opened a huge can of worms.
No one has mentioned yet, the turbo creates huge amounts of heat. The fresh air side of the turbo is about 1 " away from a 1000 degree+ exhaust housing. Yes we need to cool that air.
Along the same lines- after porting my head and exhaust manifold, I lost boost but gained volume. My power increased even though I lost boost.
It comes down to volumetric efficiency. Its about getting air into the cylinder. 1 way is cooler air, another way is more pressure, another way is larger port size. Put them all together, boost, low temperature charge air and lots of volume. That sounds like a good combination to me.
You got to love it.

 

Probably covered in another thread but couldn't find it, has anyone messed with a really BIG cac and big lines, intake, etc..? say like 4 or 5 inch with some type of massive element from industrial apps. or is it water/meth time when you want the big freeze, i'm talking daily driver, low maint. here. If this has been covered, please redirect.

 

I installed an 03 air charge cooler on my 92, its more than twice the size of the stock first gen cooler. it has 3" piping instaed of 2 1/2? It helped my EGTs A whole lot.
I have seen some of the real serious guys make a twin inlet intake set up with huge piping. I know its being done, Im trying to keep mine an everyday driver, not to extreme.