I have a stupid question, don't really know about intercoolers, but do intercoolers replace the radiators?

no.

Intercoolers cool down the intake air (the air thats going into the engine to burn the fuel) to help prevent detonation (which is where the air/fuel mixture explodes when its not supposed to). You'd only ever use an intercooler on a turbocharged car because the way turbos work tends to heat up the intake air quite a bit. The intercooler tries to brings the temperature back down to around ambient.

Radiators just cool down the engine's coolant so that the engine runs cooler.

If your intake air is too hot, then you will need both. Normally, the intercooler either goes on top of the engine (top-mount, like stock WRXs, GTi-Rs etc.) or in front of the radiator (front-mount, like most heavily modified cars). If your car isn't turbocharged, an intercooler will do absolutely nothing.

-Mike

Nope.. intercoolers are used on some turbocharged cars to cool the air coming from the compressor side of the turbo and flowing towards the throttle body/engine. radiators cool the liquid that flows around your engine to keep it from overheating and fuzing metal to metal type thing... oil also helps do this.. when combined with an oil cooler it does a much better job...
by the way.. what brings you to the past z cars forum to ask that question?

Yea seriously... I hope you got your question answered, but next time try and ask questions in the proper sections. Thank you.

Thread closed...

(O and by the way, the proper forum for this question would be the 'Forced Induction' section)

-Wes