morning,
have been reading up on intakes and seems that the feeling is that "cold air intake" is best. i am leaning toward a volant but wondering just why is cold air the best way to go, what does it do to make our trucks run better?

i do notice that in the morning when cooler my truck seems to run better. what's that all about?

thanks,
david
socal

 

Cold air has more oxygen molecules per volume of air injected into the motor. The denser the air, the more efficiently the diesel can be burned to yield more power per psi of boost. ks

 

An open intake( cone on a stick with no box around it) is recycling the heat the engine is producing.

 

Like everyone said, runs better and more efficient. Thats why a cold air Box is important. That is also the purpose the intercooler on our trucks, it cools the air that has been heated as it is compressed in the turbocharger. Just a little info for you.

Matt Sandt

 

simple answer is air density.....it doesnt matter what the temperature of the incoming air is our turbo will flow the exact same amount of air, but as the temperature of air decreases (simple laws of gasses) the volume decreases, and thus the density increases.

So for example if our turbos flow a maximum of say 1500 cfm (just a number out off the top of my head not sure if it is actual) which is cubic feet per minute and the temperature is 68*F (20*C)then we know by mass the oxygen content is 21% of whatever mass that is. However if the temperature of the air is 104*F (40*C) and there is noe pressure change that 1500 cfm of air is effectively reduced by half equalling 750 cfm. Meaning the oxygen content is only 10.5%, which lessens the combustion efficiency, thus reducing maximum power.(im canadian and do not know the formulae for standard measurements, only metric).

 

It is true that cold air will increase power and the idea of a "cold air" intake is good.

However most of the research and test results you will see on "cold air" is done on naturally aspirated engines.

The problem with trying to get cold air into a CTD is that you run it through a turbo which heats the air tremendously and then we run it through an intercooler which at best will return the air back to ambient temperature.

Now the arguement for a cold air kit on a diesel is that cold air is more dense and you can get more air into the engine if you get cooler air to the turbo and this is partially true, but the gains of cool air versus warm air is minimal in these trucks at best.

The main thing you need to do is get your intake tract un-restricted. That is where you see 99% of the gains with any intake kit on your truck. It is not the cold air, but the volume of air you gain by going to an aftermarket system.

 

I'm new to diesels but being that there is no spark plug and combustion is caused by the fuel being heated, wouldn't there be a point theoretically where the air was too cold for the diesel and cause other issues?

I would imagine that this temperature would be higher for a diesel than a gasser?

Dumb question?...

 

This is true to a point. This is why yer heater (wait to start light) stays on longer when the outside temp is less than ~60*F. It's heating the intake air before start up. After the truck starts, the compressing action done on the air by the turbo keeps the intake air significantly heated. The limiting factor in cold weather is the diesel fuel itself. When it gets cold enough, wax will start to form and make it want to resist flow. Not sure what temp this happens at, but it's gotta be pretty cold.