On low boosted cars it should make some difference. Once you get over 7 (around 7 is where having an IC starts to make a difference) it probably doesn't help much but still a small amount. The turbo will heat up the intake charge anyway making the fact that the air was once cold a moot point. Once you get into the realm of big boost I can't see a CAI doing much good.

Granted this is considering that you're not doing something stupid like having your intake right next to your exhaust manifold. If that's the case you'd notice gains from going to a CAI. But in general I can't see it doing much good on decently boosted car.

 

I would think you'd need to look at a MAF upgrade rather than a CAI.

 

Originally posted by G32BTurbo-
"but why? the "cold" air would pressurize in the turbo and become hot again"-

The turbo will only heat the air up so many degrees. If it is colder to begin with, it will be heated up that much less.

Kind of like the opposite of the air conditioner in your car. It can only make air coming in from the outside of your car so many degrees colder. On a day when it is 100 air temp. your air conditoner will only be able to make the air say 70 degrees, but on an 80 degree day, it can freeze your butt off.

 

OOooooooooooohhhhhh.... that makes sense!

 

That's not how an A/C works ... it doesn't produce cold it removes heat.

It's rated to be able to remove a certain amount of heat. So it just has to be on more if the day is hot compared to a cooler day. The air temp doesn't directly effect the temp of the air it produces. It only will if it was somehow so hot outside that the ambient temp was greater than the air conditioner when it was on (which is nearly impossible) ... and even then the cooling by convection caused by the fans would allow it to cool some.

Yes temp will effect how an A/C system works, but not how you described it.

 

but is he right about the turbo part?

 

Read my first post.

A CAI will effect a turbo car, yes. But at higher boost the pressure increase causes a temperature rise that is so much higher than ambient it overrides the temp difference the CAI gives you ... which is why high boost requires an intercooler.

Maybe numbers will make more sense. Compare 20 and 40, pretty big difference right? 100% Now add 200 to both of them. Now the difference isn't nearly as great. 10%

All of this is practically a moot point since humidity has just as big of an effect (if not greater) than temps do. Getting a CAI for a turbo car certainly won't hurt anything.

 

I also figure that a larger turbo would benefit from CAI because it spins slower to produce the same or more boost than a small turbo. Take a t25...that little bitch spins so fast to produce 10 psi. Then take a 20G, at 10 psi it is barely moving in comparison. The friction from the speed of the compresor wheel produces heat. If it moves slower, there is less heat.

 

No ... actually the increase in pressure causes the heat. The speed of the turbo has next to nothing to do with it.

The only differences in temp between a big turbo and a small one boosting the same psi would be due to piping size. But that's a completely different can of worms to get into -_-"