[A_reid93]

I have a 2016 malibu with the 1.5t and i noticed that i dont get the fuel economy that i am expecting from the car. Now i purchased my car used and i realized the factory air dam that sits below the front bumper is missing from my car. I was wondering does the air dam affect fuel economy significantly enough to notice it?

 

[campb292]

I can't imagine there is a major impact from that missing part but there could be measurable from additional undercarriage resistance. That part missing could lead to other questions though.

Before all that, what sort of numbers so you see in the info menu ECO last 450? Have you manually calculated over a couple tanks (miles driven ÷ gallons pumped)?

 

[A_reid93]

I haven't done any exact calculations but with a mix of city and high way driving I will average maybe 25 mpg.

 

[campb292]

Do some hand calculations over a couple tanks and also let us know what the last 450 says in the DIC. Gotta start somewhere then I can at least move on to ideas.

 

[DrivenDaily]

Some other info not yet present in this discussion:

How many miles on the car?

What kind of maintenance has been performed?

How many miles have you driven the car?

What brand and octane of fuel do you use?

 

[cp-the-nerd]

I've seen in a few places that the air dam is worth a fraction of a mile per gallon at highway speed, you'd never be able to notice the difference. It's one of many tiny design elements that made a bigger difference when all added together.

Your used 2016 Malibu could be under-delivering for many reasons. For one thing, it's summer and the heat takes a toll on turbocharged engines, especially if you are running regular gas. You should try premium for a few fill-ups. My wife runs premium all summer in her Cruze turbo because the heat sucks the life out of the engine on regular gas, which is also detrimental to long term reliability.

It may also be the case that your car is suffering from carbon build up because of the direct fuel injection. You might need to have the ports and intake valves cleaned out by a mechanic.

Those two suggestions are assuming your car is up to date on basic maintenance like engine air filter, proper oil change, tire inflation, etc.

 

[campb292]

If only we even had some data to see if there even is an economy problem. So far no data from manual calc, not even a last 450 DIC report.

 

[A_reid93]

Yes sorry guys overall my economy isn't bad and much better than my last car I should have clarified as this is more of a general question about the air dam. Since I've had the vehicle I've kept up on maintenance and due to the nature of the car being direct injected I do make it a mission to put injector cleaner every 6 months in the car. I would provide data so since I'm working from home right now and when I do drive it's only city it would be inaccurate to my normal driving habits.

 

[DrivenDaily]

I've seen in a few places that the air dam is worth a fraction of a mile per gallon at highway speed, you'd never be able to notice the difference. It's one of many tiny design elements that made a bigger difference when all added together.

Your used 2016 Malibu could be under-delivering for many reasons. For one thing, it's summer and the heat takes a toll on turbocharged engines, especially if you are running regular gas. You should try premium for a few fill-ups. My wife runs premium all summer in her Cruze turbo because the heat sucks the life out of the engine on regular gas, which is also detrimental to long term reliability.

It may also be the case that your car is suffering from carbon build up because of the direct fuel injection. You might need to have the ports and intake valves cleaned out by a mechanic.

Those two suggestions are assuming your car is up to date on basic maintenance like engine air filter, proper oil change, tire inflation, etc.

Yes sorry guys overall my economy isn't bad and much better than my last car I should have clarified as this is more of a general question about the air dam. Since I've had the vehicle I've kept up on maintenance and due to the nature of the car being direct injected I do make it a mission to put injector cleaner every 6 months in the car. I would provide data so since I'm working from home right now and when I do drive it's only city it would be inaccurate to my normal driving habits.

You have an engine that uses GDI - gasoline direct injection. My 2011 V6 uses SPI - sequential port injection.

The difference is that I can use a fuel system cleaner and/or injection cleaner and it will help with cleaning any deposits on the back of the intake valves.

Your GDI will not benefit at all from an injector cleaner when it comes to deposits on the intake valves. The fuel never sprays on them. The build-up is from oil and other contaminants found in the intake system that collect on the extremely hot valves and cook into a very hard film. It builds up until the airflow is seriously affected, reducing your fuel mileage and sometimes the overall driveability.

To clean a GDI engine, it usually needs a visit to a shop for an expensive cleaning operation.

 

[jfl330]

I think the biggest thing you need to be concerned about with the missing air dam is overheating. Like most modern cars, they are bottom breathers and the radiator gets its air from the bottom, very little actually goes through the grill. You A/C condenser also gets its air from there.

 

[cp-the-nerd]

I think the biggest thing you need to be concerned about with the missing air dam is overheating. Like most modern cars, they are bottom breathers and the radiator gets its air from the bottom, very little actually goes through the grill. You A/C condenser also gets its air from there.

Why would the radiator have cooling issues with this much front ventilation? Are you saying the air dam contributes to airflow in the lowest of the 3 openings I have highlighted? I'm not seeing how that would work.

 

[jfl330]

Yes, majority of the air goes up from the bottom, not through those openings except at low speeds.

 

[cp-the-nerd]

Yes, majority of the air goes up from the bottom, not through those openings except at low speeds.

What I'm not understanding is how the air dam under the car and several inches back contributes to air flow going into the lower opening in the photo. The lip spoiler ought to keep more than enough airflow to the radiator even when the middle opening is closed with the active shutters on the highway.

 

[campb292]

I also do not understand how the missing air dam would lead to overheating. If the engine were to be overheating the active shutters would open. The shutters are controlled by vehicle speed, coolant temperature, fan demand state, refrigerant system pressure, A/C compressor state and ambient temperature. You even get a CEL if the shutters are closed and not responding to an open command.

 

[DrivenDaily]

I'm not sure how the Gen8 and Gen9 are constructed, but my Gen7 has the upper section completely closed off by plastic behind the actual grille. Only the very bottom and about 1/2 of the center are open.

The only way I could see an air dam helping with the cooling process is if it creates enough high pressure in front of it to cause the air flow to deflect to the higher openings with a slightly increased pressure. With it missing, the air will still flow through the upper openings at a rate high enough to cool the engine.

The air dam is more likely there to reduce the amount of air flowing under the car, which is full of things that grab it and try to slow it down, so by going around another way, the air is flowing around stuff that is smoother. At least that's how it has been explained in the past.

 

[dequardo]

They aren’t there for show. They have been engineered to optimize cooling and drag. Also inexpensive to replace.