The air doesn't stay inside of the pipe long enough to get hot. Besides, that air would be colder no matter what.

 

^^^That's right

 

but what makes this air colder than the stock? is it the filter? ive heard mixed opinions on this.
thanks

 

It's because the filter is lower than the OE location, and because of that, the air that is first coming into the fenderwell - which is the coldest - is the air that's being sucked in.
Cold air + gasoline + spark =