I bought an indoor/outdoor thermometer with humidity reading on it today. Detached my K&N filter (mini mania intake) and placed the sensor just inside the intake tube. Have been driving around making observations with the digital readout in the car with the intention of insulating the airbox after the car cools down, then re-testing.

Observations: Here in Virginia, it's about 77 degrees with 48% humidity. The new thermometer seems to read high, but as a baseline, while driving, the digital readout usually reads 10 deg. higher than the thermometer on my tach. So, during approx 20 minutes of normal driving (city & highway) the intake temp hovered right around 87 degrees.

The significant thing to me is that when I parked the car in my driveway and left it running, the temperature climbed to 117 degrees in about three minutes. I'm thinking that insulating the box will help slow this down.

I'm thinking primarily in autocross (or drag) situations, this heat increase could rob horsepower during your run. After sitting in line for a while or even just waiting at the starting line, the temps can rise more than 30 degrees.

I know the intercooler temp is more important, but do you guys think this temperature fluctuation is significant. I don't know all the details on intake/intercooler temps, except that colder is better. Any thoughts? JR

 

Nice report !
Let's see what the experts have to say.

 

Well, I insulated the inside of the airbox with metallic/foam pipe tape, then did the identical route I had done earlier. Observations were as follows. The outside temp had climbed to 83 degrees yet my intake temp remained a steady 85-86 degrees. Earlier the outside temp was right at 77 degrees and the intake temp stayed right around 87. I guess this could be within the margin of error for both thermometers, but at face value, the insulation seemed to help keep temps down at the least 2 degrees...at most 8 degrees, depending on how you figure it. (for example, if you take the first reading as the baseline, the difference between outside temp and intake temp is 10 degrees. With insulation, the difference was only 2-3 deg.)

The bad news is that after my test run, I let the car run in the driveway for the same three minutes, and the temps climbed at the same rate to over 120 degrees. In both tests, the intake reading remained above 105 degrees after the car had been shut off and the hood opened for an hour or more.

I'm wondering if the heat rising is definitely coming from the engine bay, or if it's "backflow" from downstream of the intake. In which case, the insulation would have no real effect.

At any rate, I took the insulation off. Might mess with it some more later. If nothing else, I learned a little about intake temps. Any comments? R

 

Its good info but in the end the only thing that matters is intake temps post intercooler. Whatever you generate idling at a stop is disappated as soon as the car starts moving.

Im not sure how effiecient the MCS intercooler is....its very small and I dont imagine it gets a heck of a lot of airflow. Im also not sure how effiecient the blower is.

I will do some testing on my S when I recieve it. I have a Davtron intercooler temp sensor. Its very fast reacting, very accurate and has sensors for both pre and post intercooler.

Id be very curious to see how much heat that little blower creates.

 

Thanks, Punisher. I figured it might be a moot point. Maybe this kind of test would be better on a regular Cooper. Maybe not. Looks like intercooler mods will be the hot item this year (seriously, no pun intended). JR