Someone please tell me the finer points of what the heat exchanger. is it part of the intercooler or an add on?

 

SS's have a stock H/E right behind your A/C condensor. It connects the the coolant pump at the front of the car. It is a seperate system from your radiator. It helps keep the air cool as it runs through your engine. Without it, you could overheat your engine quickly.

 

so the OTT heat exchanger is a replacement?

 

Every Cobalt SS/SC comes with a heat exchanger from factory. The ones that you see online, from OTTPerformance for example have a bigger core and hold a lot more coolant. What it does is help prevent heat soak and lower your IAT2 temps. Don't really know of any other way to explain it. Air passes through it and instead of cooling more air like an intercooler does(air to air) it cools a liquid(dexcool/distilled water...whatever you run).

No, not a replacement. You can take out your factory one but I run the OTT H/E in conjunction with the factory heat exchanger.