Mileage/air dam question

Who knows, your probably right.

But then again, stick your hand out your window at 45mph with your palm facing the front of the vehicle and see if you feel any force against your hand.
When I took mine off I know I gained 35 hp to the front wheels alone .

 

I took mine off of my sport and noticed a .8645789 mpg increase. Definitely

The reason why the Offroad gets better fuel mileage is that cheap plastic around the fender... cuts down on the weight.

But that could be offset by the ugly chrome thats on the bumper. Who needs a "Im stuck, get me out" button anyways?

 

thread is dumb.

In SR5 trim you can have 4x4 and the air dam...best of both worlds.

 

The EPA has nothing to do with the airdam, if that was the case it would be on every single model Tacoma including the upcoming Pro.

 

Yeah, that entire statement is bollocks. They put it on so they could attract buyers who place mileage as a priority concern and be able to legally advertise those better figures. Which, if you're paying attention, means that it works. All this anecdotal horsepoop is just that. Until you run two identical trucks, identically loaded, side by side down the road at highway speeds and record the numbers, all this chat is just conjecture. And a good amount of it stems from insecure people who are overly preoccupied with how it 'looks'.

 

exactly

air dam reduces drag which increases mpg which allows them to make statements to consumers about specific MPG

if the air dam did not do anything, no one would use them.

 

+1

Toyota isn't going to install an air dam on a truck so intensively aero tested (for a Toyota Truck) unless it did something beneficial to MPG. Annnnddd, lo and behold it appears that is *does* help MPG. Just look at Fuelly. Low # of folks with Limiteds and SR5's, but the data still points to the TRD OR having the lowest MPG. TRD Sport is a full 1 MPG better. Here are screen caps since apparently no one will just go and look themselves.





TLDR?; your air dam probably nets you "nearly" a 1 MPG improvement in mileage. Take it off for looks, but it'll cost you a few pennies in old dinosaurs over time.

 

I'm all about objective comparison, but isn't the OR geared a bit lower than the Sport? If so you cannot say that the airdam is the only thing influencing the difference in fuel economy.

 

Nope, I have seen nothing saying the OR is geared differently than a Sport, all else equal. Please let me know if I am missing something!

https://www.tacomaworld.com/threads/2016-gear-ratios-at-awesome-mt-now-with-double-overdrive.387347/


Edit: of course any other item of difference between the trims will potentially have an influence, but the air dam is engineered for mpg...

 

Thanks to the folks who are pulling real data and information.

I agree: Air dam does something or they wouldn't sacrifice the ground clearance and looks.

Nobody has mentioned tires, but the OR tires are likely higher rolling resistance than those on every other model. It would be interesting to compare tire/wheel combo weights since we know that has an impact based on folks upgrading to larger, heavier tires . (I realize that diameter is a factor on the upgrades, but weight is also a factor).

I don't believe feully sorts for transmission and 4x4 vs. 4x2 and both are certainly a factor. It seems likely that more folks with the OR get 4x4 and there could be a difference in take-rate for transmissions.

I have observed much lower mileage when I've been off-road at some point while burning a particular tank of fuel (see big dips in chart below). This drags down my average. I think it's likely that folks with OR's take them OR more often (see what I did there? Yeah, lame. I know). I suspect this is pulling me down about .5 mpg. [Note: Fuelly needs to do a better job with their charts and the vehicle sort options]

 

This is the issue I see with the fuelly data, there is no designation of 4x4 vs 4x2.

But from the data provided, we can assume that 4x4 Tacoma's will average 18-19mpg, because ALL off road models are 4x4. Also there are 37 vehicles in that data group.

The other models seem to be getting between 19 to 20 mpg, however, there is no indication of how many of those are 4x4 or 4x2.

But if you look at the fuelly data for the Limited, noticed how the MPG reporting is consistent between 18 to 19 mpg, (the same as the 4x4 off road model) but there is a spike for the 20 mpg. Granted the graph is skewed because there are only 5 trucks in that group, but it could illustrate the difference between 4x4 and 4x2 Limited.

So my question is, how do you measure the gains from that front deflector?

Also how much does the extra mass of 4x4 components along with driveline drag offset the effectiveness of the front deflector?

I would assume they do hence the dedicated 4x4 off-road model doesn't come with the deflector. Plus to compliment its aggressive looks, and off road bad assness, Toyota left it off.

I know I was joking earlier, but seriously, I have not seen a loss of MPG since I took mine off. My truck is a 4x4 Limited, which also has some other contributing factors such as 18'' wheels and that heavy ass bed cover.

With the front deflector, around town I was getting about 17 to 18 mpg as my tank average. NOTE that is my tank average! I've filled up twice since I removed it and my tank average is about 18.6 to 19. My results are consistent with the data from fuelly for the Offroad Tacomas.

As for the highway, when I had the deflector, I got 25mpg on the highway (trip mpg). The other week when I went to the Tamorlando meet, I got the same 25 mpg (trip mpg).

So this limited data tells me there isn't a huge benefit if your running a 4x4 Tacoma. But if it's a 4x2, then it will have more of an effect, granted your probably getting more gains by not having all of the hardware that the 4x4 trucks have to lug around.

 

I stand corrected. I thought the locking diff had a different ratio but I can't remember where I saw this. My bad.

 

Not all off roads are 4x4...

 

Shit your right, I missed the one 4x2 on the build site. Well forget everything I said.......but who buys a 4x2 off road?

 

Yeah, I agree, a TRD Off Road 2x4 is a bit of an oxymoron lol. But I guess if you like the look and features of it and don't need 4x4...

 

I think it carries a higher mall rating then a 4x2 sport I guess

 

I think tires may be a valid delta. Tranny differences are probably negligible since the % of manuals are produced is in the single digits. 4x4 and 4x2 definitely should be separated, but the overall assessment that the airdam gets you somewhere between .5 and 1 mpg is probably close enough. I wouldn't lose sleep over removing it if a person wants to.

 

How about they have the air dam on it to compete with Ford and Chevy whom also have air dams.... My truck looks a lot different from the front with it removed. To me it looks like the air would move more easily thru and under the chassis with the air "dam" removed. Kinda spells it out in the description
"air dam" - if it was a water dam then it would be holding the movement of water back... I think it's doing the same thing here in this case with air.

The way the air moves around my truck without the dam - the air now hits the front skid plate that is angled down and away. Definitely better aerodynamics that a flat 4" flap straight up against the air sorta looks like a small plow and nothing to do with air movement for aerodynamics. I'm guessing it's there for looks/aesthetics than for aerodynamics or they'd have it on all the trucks. just sayin...

In all seriousness something like that would have a very minimal play in MPG and I would think it would be for the negative not a positive for MPG. How about its there for "looks" and marketing thought it would help sell more trucks, that would be my bet. It kinda hides what my truck looks like now without it. MY truck just looks a lot more mean or more masculine like I'm ready to go off road ... hey there's an idea!!

 

Because it "looks" like a dam? Hmmm? .....from what background do you base this expertise in aerodynamics?

The air dam reduces drag by deflecting air away from the underbody of the truck. Air going under the truck increase drag because of the rough underside. So this "dam" improves efficiency by pushing the air to more efficient or "slippery" areas around the vehicle.

Here's a random GM article about it: http://media.gm.com/media/us/en/gmc...news/us/en/2013/May/0516-gmc-pickup-aero.html

I am sure there are more and better sources out there...

 

This.