Wired a thermocouple under the hood today and went for a drive. I was surprised by the results.

My probe was placed about 3 inches in front of my HKS filter, and wired back to the dash where my multimeter was propped up.

Ambient air temps ranged from 68°-72°F over the course of my 20 minute drive.

While the car was still warming up, I saw the same temperature under the hood as outside the car- not surprising.

After the car was warmed up, at any speed over 15mph, under hood temps at the intake were never more than 8-10°F over ambient providing you had clean air.

The crazy part was how fast temperatures would rise at a standstill. Waiting 20 seconds at a red light would bring under hood temps up as high as 135°. Fortunately, once you broke the 15mph barrier, temperatures would plummet as fast as they had climbed.

Drafting would raise under hood temperatures an additional 5-10°F over what I was seeing under clean air driving.

This is nowhere near the results you'll see on AudiWorld relating to before/after testing of Schwings cold air intake. I believe the differences are car to car related. I don't know what exactly his setup was, but I can tell you what you'll find modified on my car.

1. I don't run with the plastic belly pan (more airflow)
2. I have no seal/trim across the top of my firewall. I'd assume this provides a small amount of cowl induction. (more airflow)
3. My battery is relocated to the rear, freeing up more space under the hood (more airflow)
4. Car is significantly lowered, and raked forward. Assume modified airflow.

Everyones car is going to react a little differently, but the point of this exercise is that you should actually do a little testing on your own rather than base your decisions on what you read online. Schwing applied a scientific process to his testing, but his results are still only his results unless you copy his setup.

 

There was a simular test done with a basically stock underhood (even airbox) and the temps never changed anymore than what you posted. I have stated all this to people for a long time now. If i can find the thread, i will post it. Glad there is now FINALLY a handful of people ?'ing steves claims and posts.

 

It's always a bunch of talk and never any hard data. Hearsay is only that, and I'm not one to believe something just because someone on the internet says its true.