Are Cold Air Intakes Worth it?
There has always been a big hype about getting a cold air intake. Well its been brought to my attention that cold air intake doesn't work as expected on turbocharged engines. My second in command on the forum ISX is a wizard of sorts when it comes to figuring out math formulas and calculating different things on the Cummins engine. From his research in this, there is such a small difference in volume that you'll never see a measurable difference in power.
Quote ISX post.
I've run the numbers and had a temperature probe on the air filter and the highest I saw on a hill pulling the trailer at 100°F was 20 over (120°F). After plugging in all the numbers, you end up with a 0.5% gain in air mass in the cylinder when compared with what a cold air intake would provide (100°F air). As a reference, 0°F - 100°F ambient changes air mass by 21%... In other words, because of the intercooler, the cold air intake and heat shield stuff is null and void. You will never notice a 0.5% increase plus that is only under high load conditions, most of the time I was only seeing a 10°-15°F rise and in the winter, I saw almost no rise over ambient. Even if the temp was 50°F over ambient, it's still only 1.5% more air mass. It's all because of the intercooler.
I know a lot of guys run heat shields and stuff and I'm not trying to say they are bad I'm just throwing the numbers out there. There could be something to how much boost is produced with hot air vs. colder air within the turbo. But turbo efficiency has more to do with it than anything IMO.
So what I'm suggesting for the 2nd generation crowd is just get a BHAF for an air filter. As for colder intake temperatures you could upgrade intercoolers but the stock intercooler is already like 90% efficient. So there is going to little to no change in air temperatures with even a upgraded cooler. This will, of course, change as your performance demands change. But for mostly stock to mildly modified truck, the stock intercooler is going to work just fine. Typically for the 24 valve engine, there is a roughly +40°F temperature rise in the manifold because of the coolant jacket in the intake manifold. Also, the coolant jacket is within a few inches of the IAT sensor. So there is always going to be warmer air in the manifold.