MPG? FYI. Why Your Tacoma Gets What It Gets

I've been wanting to write on this topic for awhile now. I will try to keep it short, but that's a tough ask on this topic. I am writing this in layman's terms for ease of concept understanding so there will be minor errors, like weight versus mass. I know this is old news to some of you, but, judging by the number of mpg threads, it will be new news to others!

It seems every other day there is a new MPG thread that pops up here, and that's fine. People, especially new guys, are concerned about their new truck's efficiency and want to make sure there is nothing wrong with it. The response "If you wanted good gas mileage you should have bought a Prius" is absolutely correct. However, they bought a truck and want to know if their vehicle is in line with other trucks like theirs.

Those same threads also have posts like "My other truck has 395 HP and it gets the same gas mileage as my Tacoma!" Well, I am going to explain that too. Let's start with efficiency:

Efficiency
Guess what... your new Tacoma's engine sucks with respect to efficiency. The good news? So does every single other internally combusted gasoline engine from every single manufacturer. The AVERAGE thermal efficiency of a modern gasoline engine is around... wait for it... 20-25%. That's it. Whether it's a Ford, GM, Toyota or Dodge, every single one of their engines are terribly inefficient. This means that, for every gallon of gas you pump in to the tank, only about 25% of the energy contained in that gallon of gas gets used. The other whopping 75% is wasted, in heat! For comparison, an electric motor is about 90% efficient! Which is why it kicks ass in the mpg department. So what do manufacturers do? How come competing vehicles get a bit more mpg? How can we fix this? Why are we not driving electric trucks? Why does my underwear twist? Well, here are some answers:

The Tricks
So now you know gasoline internal combustion engines suck with respect to efficiency and diesel has its own problems, like acceleration, environmental, etc. What makes a Ford Truck get better mpg than a Tundra for example? Well, every manufacturer uses "tricks" to improve the overall efficiency (mpg in this case) since they can't improve the inherent design flaws of an internal combustion engine (we will call it ICE from now on). Here are some of the tricks:
1. Atkinson Cycle
2. Stop Start tech
3. Cylinder Deactivation
4. Turbo
5. Supercharge
6. Aluminum Construction
7.Etc
So these are the main tricks manufacturers use to improve a vehicle's mpg. Even after over 100 years of design, the engineers still can't improve the efficiency beyond about 25% without resorting to the above tricks. Each of these tricks have good and bad points. The good points are they improve mpg and in some cases give you more hp. The bad points are reduced reliability and durability of certain components, increased complexity plus increased cost in some cases. But, they do help increase mpg and that's what the average guy wants right? Now, let's move on...

Why My Tacoma Gets What It Gets
So, yesterday I read a post where the guy couldn't understand why his 350 hp full size truck got the same mpg as our 275 hp mid size Tacoma. How can this be? Sorcery? Black Magic? The answer is quite simple lol. Now, if you don't get anything else from this article, please retain the following for your future conversations:
More horsepower only makes you go faster. Boom. Let me say it again: More horsepower only makes you go faster. Got it? Let me explain in more detail:
If you have a Hellcat (700+ hp) you will have better 0-60 mph times than our Tacoma with 275 hp. No brainer right? However, even with 700+ hp, the Hellcat gets better highway mpg than our Tacoma! This is not an apples to apples comparison though. Another key point: In order to make a comparison, you must understand the differences between vehicles. For example, our truck gets around 20 mpg. A v6 Chevy Silverado Crew Cab gets about the same. If you look up the F150 Crew Cab eco boost V6 (twin turbo) 4WD it gets one mpg better. The GM mid size twins get about the same. Point is, they are all really close to the same efficiency and yet they use different "tricks" shown above to get there. How is this and why am I comparing full size to mid size?

The Physics
I am going to use round approximate numbers for clarity. Our V6 Crew Cab 4WD Tacomas with a coupla people weighs about 5,000 lbs. Guess what... so do the full sizes and other mid sizes! Yeah, our trucks have grown into big heavy pigs, but so has everyone else's trucks. Safety is the reason, but that is a topic for another conversation. That 5K weight is a problem when it comes to mpg. Why is weight so important? Now, following is another key point:
What influences MPG
1. The vehicles mass (I am going to use weight because... gravity duh)
2. Drag (aerodynamic drag and also rolling resistance of tires)
3. Driving Style
4. Geographic Location (Sea level, mountains, flat, hilly, etc)

So above are the four key reasons you get what you get, mpg wise. If you take a stock 4WD Crew Cab Tacoma, you will get around 21 mpg on highway. You get 21 mpg because of the reasons above. It takes about 57 horsepower to maintain 70 mph on flat ground in a 5K lb truck. 57 horsepower. Now, to GET to 70 mph is where the horsepower is needed! What this means is, ANY ICE vehicle that weighs 5K lbs and has similar aerodynamics driving similar terrain is going to get around 21 mpg. Ford, Dodge, GM, turbo, Cylinder deactivation, whatever. The key is 57 hp to maintain 70 mph. If it takes 57 hp to maintain 70 mph, you are going to get the same mpg. I could go into the formulas now (how I calculated 57 hp for example) but I don't think that would bring any clarity and suffice to say these numbers are close.

So, there you go. As you can see above, your vehicle's weight, drag, driving style and geographic location are what influences your miles per gallon. If you want to get better mpg,
1. Don't add weight. Weight is a killer for mpg
2. Don't mess up the aerodynamics any more than they are by lifting or adding a winch up front.
3. Drive conservatively

To Close
Now, is there a truck out there that addresses the fundamental challenges of efficiency that I listed above? The answer is YES! There is a truck currently being produced that is lighter, more aerodynamic and is 25% more efficient than our trucks! So if efficiency is your jam, I present



Lol thanks for reading and I hope this helps some of you!

 

They (Honda) can call it a "truck" --BUUUT it ain't a truck --It is a nice uni-body car with a "sorta-bed " on it- period.
Nice vehicles --but not when it comes to hauling 6-7 cords of firewood home each year.
It is a "citified hauling vehicle"
May explain why they are not selling well-- NOT A TRUCK!

 

Fake Honda commercial newz!


















Just kidding

 

BTW -- why don't you have one?

 

This is fantastic and I hope it soars like the majestic eagle it is

 

I hope you are not saying you haul 6-7 chords of wood in one trip, I call BS on that lol.

 

Nah

edit: heyo @scottalot! Been a while!

 

Toyota seems to focus on proven technology as opposed to new technologies to offer better MPGs, which I think is alright. I hope that eventually they use the proven hybrid technology from the Prius and put it in their range of utility type vehicles including the Tacoma! Or even hydrogen fuel cell based electric vehicles.

In the meantime, I am fine with the weird shifting and power on the V6 so long as it gets better economy than the 5th Gen 4Runner I owned.

 

Lucas! Lucas! Lucas! Hahahaha

 

please. This is not a di#k measuring contest. I put the pic of the Ridgeline showing what a truck that was "optimized" for mpg looks like. Get what you want, drive what you want.

 

Did I say one trip -- no I DID NOT!
I haul that much to my home every year -over the course of the year.

 

Lighter or sleeker. Got it. Personally I'm usually 21-22 consistantly which I'm happy with

 

now that's what I call economy -- getting the most out of a trip

 

Exactly. Less power is better too, for efficiency, which is where the 2.7 is!

 

Out.

 

Such a great write up! I had no idea ICE were so inefficient, makes sense but dang. Just goes to show how wasteful we are.

Never really understood the reasoning for atkinson cycle either...

Also Ford uses aluminum as a trick... have you lifted your hood lately? Damn!

 

Sticky this thread please.

Make it required reading before being allowed to start a thread in this sub-forum.

 

Except that the new v6 gets better mpg than the 2.7?

OP you over simplified this and ended up with some errors...

Still doesn't explain how my 3,500lb stock reg cab 4x4 only barely gets 20mpg when a 5,500lb full size crew cab gets the same.

I thought they were the same weight and required the same power to maintain speed? And weight was the killer of mpg? Well that's an extra ton of weight and it doesn't seem make a difference.

Then you have the tundra V8 getting what 16 at best when a comparable Chevy is getting 20?

 

I, for one, would love to see something similar done with the "what size tire can I fit" topic