[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)

[Vtor_ZL1]

You need much more testing. 20 mile sample is hardly conclusive.



Airdam also helps you run cooler as it forces air through radiator(s) and not under the car.


That is like going outside, seeing no mosquitoes and concluding, yup, mosquitoes now extinct.

[protovack]

Did you actually read my post? There was also a 36 mile test and I also described the conditions of the test. It was ideal test conditions. I also specifically said that I didn't test at high speeds, and that there could very well be a difference at speeds higher than what I was testing. But at low speeds, I can find no difference and I can assure you I've done more test runs than just what I've posted here. These are roads that I drive all the time, and I'm very familiar with how to run them for fuel efficiency testing, down to knowing how the windspeed coming from the west causes MPG to be better driving eastward. That did not happen during this test, because the wind was non-existent, which was the reason I did the test on that particular day.

"Air dams help you run cooler"--You might be mistaking air dams for older air deflectors such as those found on third generation camaro/firebirds. These deflectors routed air from under the nose upwards into the radiator, because there was no front grill opening. The 6th generation Camaro, by contrast, receives air flow directly into the radiator through the grill. Most vehicles today have an open front grill simply because it works better. Modern air dams exist for fuel efficiency, not cooling. However, most of the time people experience little to no loss in fuel efficiency taking them off. Also, routing air to the side of the vehicle has possibly negative implications for aerodynamics, which I outlined.

Since you track a ZLE, cooling is obviously very important to you. You don't have air dams. Have you ever wondered why, if air dams were so important for "pulling air through the radiator", why your car lacked them? For those of us with cars that came from the factory with air dams, these are important questions that we all wonder about.

[17rsvert]

Where are the air dams? Pics before and after?

[enzia35]

Yeah, we're gonna need pics of what was removed.

[arpad_m]

I think protovack means the rubber air deflectors (#31) in this picture.

[arpad_m]

These ones should look even clearer. I hope I didn't misunderstand the entire OP

[Lafourche1]

I know that on the SS Camaro, you remove these and put your brake cooling ducts and backing plate on the car when you are doing your track preparation. This is done to help cool the brakes.

[protovack]

thanks for posting pics, yup those are the ones.

[Giri]

Are you sure you got this right? Air dams are supposed to increase gas milage, not decrease it. Same with wind noise. I've noticed my wind noise decrease since I replaced a ripped air dam.

[protovack]

Yea I was surprised, I never expected to get a decrease in wind noise from taking OFF the air dams. But if you think about the air flow it kind of makes sense, the dams force air away from under the car out to the side, where it has to compete with a very fast moving mass of air already whipping by the side of the car. It is conceivable that this introduces oscillation in air pressure around the side of the car, and thats exactly where I was getting my excessive wind noise from.

You can interpret the MPG however you want, but IMO there is no difference at lower speeds, and maybe a slight difference above 70mph.

[mdhopt36]

Hey, those are called CURB SCRUBBERS !!!

Park where the curb is too high, you scrub the top of the curb!
********

Pretty interesting. Increase mileage, decrease noise. Next week, mine goes on the lift, so I'll take a closer look.