Why Cai?

[mrjelly]

this might be a stupid question, but whats the point of a cold air intake filter if u've got an intercooler? i mean doesnt the intercooler make the air colder or something?

[GTRgeoff]

Yes but if the intake temp is 20-60deg higher the intercooler then has to drag that heat energy out of the intake charge. Also, as air is compressed it heats, so there is already that extra temperature to resist the energy increase of compression (marginal but an impact). All elements attempt to achieve their lowest energy state which fundamentally resists an increase of energy. So the turbo won't make the same boost at a much higher intake temp. You then have to compensate for that somehow. The turbo is also running at a higher temp as it absorbs some of the heat energy of compression.

When most people are running to the margins of at least one component of their engine system, that extra heat could be the deciding factor in an engine failure. Also items that are susceptible to heat can do without an increase in the heat cycle max temps as it brings them closer to fatigue failure.

[xRHETTx]

I work for an air compressor company, we use as a rule of thumb that for every 3 degree increase in inlet temperature, you lose 1% of your output power.

Intercoolers arent magic, they cant cool the air back down to the ambient temperature, so you may as well start with the coolest air possible.