Removing Air Dam Chin Spoiler effect: lowers MPG by only ~0.7mpg fuel economy

[Gastan]

Now that we have more 2025 4Runner owners taking delivery and thinking about removing the air dam front spoiler part, the question of how much removal will affect MPG / fuel economy has come up.

So for reference -- removing the air dam chin spoiler resulted in just ~0.7 lowered mpg / reduced fuel efficiency. That's the result from TFL's testing on a 2024 Tacoma -- here's the video:



Hope that helps in your decision whether to remove the air dam from your 2025+ 4Runner 6th gen.

 

[KTRAN]

Now that we have more 2025 4Runner owners taking delivery and thinking about removing the air dam front spoiler part, the question of how much removal will affect MPG / fuel efficiency has come up.

So for reference -- removing the air dam chin spoiler resulted in just ~0.7 lowered mpg / reduced fuel efficiency. That's the result from TFL's testing on a 2024 Tacoma -- here's the video:



Hope that helps in your decision whether to remove the air dam from your 2025+ 4Runner 6th gen.

That's a negligible difference in reality. And you get much better front end clearance too, even if you don't care about its looks.

 

[qtb007]

0.7mpg doesn’t mean much to the individual but it is pretty considerable when it comes to CAFE regulations. That chin spoiler could be the difference of hundreds of dollars of fines per unit. In the industry we fight and scrap for saving cents per unit.

Of course, Toyota is only responsible for delivering it; the customer is free to do what they want. One should consider how they use their vehicle, cost of fuel, and miles driven when they decide. High miles or high cost of fuel area, I’d probably remove as necessary.

 

[John S.]

Now that we have more 2025 4Runner owners taking delivery and thinking about removing the air dam front spoiler part, the question of how much removal will affect MPG / fuel economy has come up.

So for reference -- removing the air dam chin spoiler resulted in just ~0.7 lowered mpg / reduced fuel efficiency. That's the result from TFL's testing on a 2024 Tacoma -- here's the video:



Hope that helps in your decision whether to remove the air dam from your 2025+ 4Runner 6th gen.

Thank you for your testing and post. Any idea what gain in overall ground clearance there is from removing the air dam? I'm curious how much it would improve the 9.1 inches on a 2025 4Runner Off Road Premium hybrid.

 

[Gastan]

Thank you for your testing and post. Any idea what gain in overall ground clearance there is from removing the air dam? I'm curious how much it would improve the 9.1 inches on a 2025 4Runner Off Road Premium hybrid.

Removing air dam from the TRD Off-Road should improve ground clearance about 1" which basically matches the TRD Pro (which has 10.1" inch ground clearance).

That comes from this helpful discussions about ground clearance and approach/departure angles:

Thread: Ground Clearance, Approach Angle, Departure Angle, Breakover Angle

@andim: Looks like ripping off the air dam brings the TRD off-road to almost the same ground clearance and approach angle. Not perfect but certainly good enough.

@samyota: I measured it as in the picture.

- With air dam, it gets ~22°, which is slightly greater than official 19°. Given that we'll air down when "offroading" where the approach angle really matters, it will possibly drop from 22 to 19° in reality.

- W/O air dam, it gets ~30°, which is 3° smaller than TRD PRO. I presume it's because of the higher ground clearance on the PRO.

Edited:
Make it an apple to apple virtual visual comparison, I also did it on the PRO.

 

[ModernDay4Runner]

I wonder why the Toyota engineers designed and ultimately went with the installation of the air dam to begin with.

It can't be just for the 0.7 MPG improved fuel efficiency. There has to be other considerations, I think so anyways. Any ideas out there?

 

[Rich in Texas]

I would leave it on just for added mpg. Most people will never work the truck hard enough for it to get hung up on someting. Once you stick off road tires and a lift kit on, it won't matter anyhow since mph concerns have been thrown out the window.

 

[John S.]

Removing air dam from the TRD Off-Road should improve ground clearance about 1" which basically matches the TRD Pro (which has 10.1" inch ground clearance).

That comes from this helpful discussions about ground clearance and approach/departure angles:

Thread: Ground Clearance, Approach Angle, Departure Angle, Breakover Angle

Thank you again, @Gastan. I don't do much off-roading but I do live in MT so driving in pockets of deep snow is my main concern with overall ground clearance.

 

[ModernDay4Runner]

I would leave it on just for added mpg. Most people will never work the truck hard enough for it to get hung up on someting. Once you stick off road tires and a lift kit on, it won't matter anyhow since mph concerns have been thrown out the window.

I'm interested to hear what people think of why Toyota installed it to begin with?

 

[4running]

I wonder why the Toyota engineers designed and ultimately went with the installation of the air dam to begin with.

It can't be just for the 0.7 MPG improved fuel efficiency. There has to be other considerations, I think so anyways. Any ideas out there?

I think it's purely for improved fuel efficiency. Even 0.5-1 MPG improvement is significant, especially for engineers trying to eek out best fuel economy numbers possible. Plus, it's an easy and cost effective solution in terms of engineering solutions to gain some MPG, even if not by a lot.

The only other (unlikely) reason would be for protection of the underbody - to prevent foreign objects / large rocks from sliding under the body.

 

[ModernDay4Runner]

I think it's purely for improved fuel efficiency. Even 0.5-1 MPG improvement is significant, especially for engineers trying to eek out best fuel economy numbers possible. Plus, it's an easy and cost effective solution in terms of engineering solutions to gain some MPG, even if not by a lot.

The only other (unlikely) reason would be for protection of the underbody - to prevent foreign objects / large rocks from sliding under the body.

Yes, that is what I was thinking as well. Fuel economy and protection. If my TRD sport premium comes with that I will be keeping it on. I don't think it looks bad at all and I won't be doing any off-roading.

 

[Rellims]

I'm interested to hear what people think of why Toyota installed it to begin with?

To pass fuel efficiency regulations.