Cold air induction on an S/c motor....

If you are intercooling a supercharged application does having a cold air intake matter?

What I'm trying to say is, air going into the SC is 120 degrees and 145 degrees, will the 120 degree air going INTO the SC cause the air coming OUT on the other end to be cooler then the 145 degree air.

I dont' know if when you compress air to a certain PSI it pretty much has a set temperature at X amount of PSI no matter what temperature it is beforehand.

The colder the air into the S/C or turbo, the cooler it will come out.

At 100 percent adiabatic efficiency, the formula for temperature rise in a FI system is:

Outlet Temp= Inlet Temp(Pressure Ratio)^.283

All degree are in Rankin degrees, which is Farhenheit plus 460.

Two identical engines, running 2:1 pressure ratio, but one is gulping 70 degree air while the other is gulping 170 degree air.

Engine 1:
70*F+460= 530*R

530*R(2.0)^.283= 644*R or 184*F

Engine 2:
170*F+460=630*R

630*R(2.0)^.283= 766*R or 306*F

So you can see that at the compressor outlet, a the colder the air it ingests, the colder the air will be that it puts out.

Now if you had exactly the same efficieny intercoolers for both motors you can see that Engine 1 will have a colder charge.

But with all the ehaust routing, intake piping and intercooler placement problems us turbo people have, its touch to get colder air into the turbos. For S/C folks its easier.

All in all I think its worth it, cause I believe its about a 1% increase in power with a 10* drop in intake temp. And a 500hp engine thats 5 hp....sometimes it matters.

Hunter

I guess if your running a 500+HP turbo/sc setup it doesn't matter a "whole" lot....since the intercooler is designed to bring you down to within a safe temperature...

Its not like putting a CAI on an NA engine and gaining 20HP because the stock system was restrictive and got warm air, the on a forced induction setup the gain isn't nearly as dramatic?