[protovack]

A while back I removed the air dam on my 2016 Silverado, and saw no actual decrease in gas mileage. It looked way better too. So I decided to remove the air dams on my 2.0T to see what difference it would make in terms of gas mileage. I also wanted to see if it altered the way the car feels on the road in terms of stability, tracking, and wind noise. Theoretically, the air dams deflect turbulent air away from the tires and undercarriage to the outside of the vehicle.

Removing the air dams is simple but it did take me about 20 minutes with a socket, mainly due to the awkward angle of the bolts.

The very first thing I noticed on the road had nothing to do with gas mileage. It was in fact a dramatic decrease in turbulent air flow and wind noise around the side of the car near the side mirrors and side windows. This is something that was really irritating me, and I was thinking it could be something like a side mirror not torqued to spec, or a design flaw in the air flow around the side of the car. Well, that isn't far from the truth. It appears that the air dams force too much air to the side of the vehicle, resulting in random oscillation of high and low pressure along the side of the car, which can be heard as excessive, variable wind noise around the front of the side windows and side mirrors. Removing the dams completely fixed it.

As for the gas mileage. Below are a couple images of my DIC. These trips were on gently rolling rural 4 lane highway at 60-65mph in 6th gear about 70% of the time, 5th gear the rest, without any significant altitude gain or loss, at about 70 degrees farenheit with no wind, gas tank just filled with fresh 92 octane, 2 people in car and trunk full of groceries (so a good test).

First of all, it's really impressive. Secondly, its not significantly different than other tests I've done with the air dams on. Third, NO excessive wind noise around the doors and windows.

In addition to these short trips, I also did a 600 mile road trip without the air dams, to really get a feel for the car without them. This trip I was not going for gas mileage. I was passing cars at 90-100mph frequently. On this trip, I did notice that I had to do ever so slightly more minor adjustments to my steering wheel to maintain trajectory. Like where you just have to touch the steering wheel in either direction to keep going straight. Like maybe 5% more. I presume this is due to turbulent air blowing past and around the inner wheel well. HOWEVER, I also felt like the car was, strangely enough, more stable, and seemed to cut through the air better. Also, switching to sport mode with the firmer steering solved the minor adjustments issue completely. The overall driving experience was greatly improved due to less turbulent air blowing around the side of the car. It felt more stable, and more "correct". Multiple times I had the idea that GM wind tunnel tested the car without air dams to perfection, then added the air dams to "comply" with fuel efficiency standards.

That means there must be a scenario where they confer some efficiency advantage. Maybe at high speeds, like in the 75-85mph range, which I have not tested.

But, based on my limited experimenting, I would definitely recommend removing your air dams (if you have them, cars with front splitters don't have them, as far as I can tell)