While cleaning the garage I found my trusty indoor outdoor electronic thermometer so I figured what a good day for a test of my intake temperature.
I placed the probe up in the intake of the CIS airbox. No hose is attached to the inlet so it is currently sucking ONLY engine bay air just like those fancy "cone" filter setups everyone wants to buy.
So I get ready to drive to work. Outside air is 40*F . I start the engine and without warming it up drive thru the neighborhood to the interstate (about a mile away.)
By the time I get to interstate the intake temp is up to 50*F
5 miles of 70mph driving later temp is up to 70*F
5 more miles and we're up to 80*F
It levels out at 110*F for the rest of the trip.
Here's a shocker. After all that driving when I pull off the interstate onto city roads it goes down for a second and then soars upward over 120*F and my thermoster goes overrange and starts flashing HHH
I repeated this test on the way home today and got identical readings.
So as you can see engine air is usually 80*F higher in temp than the ouitside air. Now let's pretend is a sunny summer day and it's 80*F outside. Wanna guess what your "cold" air intake is doing? Cooking your friggin engine that's what! You should have at least 160*F or worse due to the added rays of the sun baking the car itself.
Now let's add in that turbo you always wanted. Any idea what your intake temp might reach?
Now if I get time I'll hook the usual front bumper intake back up and see what's "normal" for a 1.8 CIS setup.