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2014 Toyota Corolla's gasoline engine bests diesel rivals' MPG and emissions

In just the latest example of gasoline cars busting the diesel myth the 2014 Toyota Corolla LE Eco's 35 MPG combined beats its diesel competitors' fuel economy. A close look at the match up reveals the Corolla also has the lowest emissions and lowest fuel cost to operate per mile in any situation.

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At a recent Toyota product launch for the midsize 2014 Corolla, Toyota’s representatives stated that the new 2014 Corolla LE Eco is the segment’s gasoline powered, non-hybrid fuel economy champ. Based on our analysis it seems as if the 2014 Corolla LE Eco is more than that. It is the most fuel economical mid-size family car period (non-hybrid). It also has better green credentials.

Fuel economy is not which car gets the best mileage (the Corolla does by the way). Rather, fuel economy is the measure of how economical a car is to run in terms of fuel cost, and it is not the same for diesel and for cars that use regular gasoline. Diesel is more expensive and that has to be factored in for a fuel economy analysis. Let’s start with fuel efficiency, which is a measure of how far a car can go on a gallon of fuel.

The 2014 Toyota LE Eco with its standard wheels gets 35 MPG combined. One Toyota representative we spoke to was firm in their confidence that this number will not be an exaggeration like the Hyundai numbers of a few years back. In fact, according to our source, the EPA verified the test for the Corolla themselves, rather than trust Toyota. The Chevy Cruze diesel gets 33 MPG combined and the Jetta 34 MPG.

On the highway the Cruze beats the Corolla in fuel efficiency garnering a 46 MPG rating. Corolla gets 42. However, when we compare fuel economy using $ 4.00 as the price per gallon of diesel, and $3.40 for regular unleaded, the Corolla again wins the fuel economy battle costing just 0.081 cents per mile versus the Cruze at 0.087 cents per mile on the highway. These prices are real in the author’s area today. Yours may vary.

Next, let’s jump to the environmental arguments. According to, the 2014 Corolla LE Eco produces less CO2 per mile than either the Volkswagen Jetta diesel or the Chevy Cruze diesel. The Corolla weighs in at 257 grams per mile, then the Jetta with 297 grams per mile, then the Chevy Cruze with 307 grams per mile. It seems sort of hard here for the diesel folks to claim any sort of victory in terms of environmental benefits versus gasoline.

Let’s now look at the diesel societal-benefits argument. Despite diesel car advocates trumpeting their favorite fuel’s miraculous abilities, diesels are neither more fuel efficient, nor more environmentally friendly than modern gasoline powered cars. Let’s now review how we get either diesel or gasoline. We get either and both, from a barrel of refined crude oil. Currently, according to a wide number of sources, a barrel of refined crude in America yields about 19 gallons of gasoline and about 11 gallons of diesel. Diesel lovers can wish otherwise, and we are willing to be proven wrong about this, but by all accounts moving to diesel does nothing to reduce America’s dependence on oil, foreign or otherwise. In fact it moves us in the wrong direction.

Thus, we have established that the Toyota Corolla has better fuel efficiency in terms of combined mileage than the two diesel cars it competes with. We also have shown why the car is more fuel economical, even on the highway than the Cruze. Furthermore, we have proven that the environmental measurements and societal measurements most commonly associated with cars favor the gasoline car over diesel. In terms of pricing, similarly equipped Corollas are just a bit less expensive than the Cruze, and much less expensive than the Jetta (about 20% lower). Corollas also have two years of free maintenance which means lower overall cost of ownership.

Just in case the diesel advocates wish to explain away the Corolla LE Eco as some sort of fluke, let us spoil the fun by also pointing out that the 2013 Nissan Sentra gets equal fuel efficiency (33 combined) and has lower output of CO2 than the Cruze. In fact, the Civic HF does as well. And the new 2014 Mazda 3. All are more fuel economical than all the diesel cars in their class.

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Michael Reiche (not verified)    August 19, 2014 - 8:13PM

If a Cruz diesel gets 33mpg combined, would a Cruz Eco diesel get 36mpg combined?
A comparison of the same car in gas and diesel would be interesting in terms of gas/diesel wars.

" $ 4.00 as the price per gallon of diesel, and $3.40 for regular unleaded"
" These prices are real in the author’s area today. Yours may vary." shows the difference being more like 33 cents for the week of 7/14/14. Just sayin'

Old Jetta (not verified)    November 11, 2014 - 11:11PM

I get 50 mpg routinely with my VW Jetta, and I also burn 100% locally-produced soy biodiesel (B100), which is carbon neutral. I'm waiting for a car that can do this and isn't 11 years old. Why quibble pettily over the lackluster models in the article? In this age where we rape the earth for a drop of oil, anything under 50 mpg is not worth considering..

J (not verified)    April 9, 2015 - 2:38PM

In reply to by Old Jetta (not verified)

Carbon neutral? Growing crops isnt carbon neutral because you do it on land that would otherwise absorb carbon. Especially in Brazil, soy crops replace forest. Maybe that forest was leveled a long time ago where you live, but where forest can be sustained by climate, growing soy in place of carbon absorbing natural vegetation isnt exactly carbon neutral.

Old Jetta (not verified)    April 9, 2015 - 3:09PM

In reply to by J (not verified)

You raise a good point and I agree with your statement in theory, but I would need numbers to back that up. How much carbon dioxide is absorbed by an acre of forest vs let's say an acre of camelina? I think there are good reasons to not cut down forest that have nothing to do with cutting it down for biofuel. However, given the assumption that you are using an acre of land for fuel production that was otherwise unused, the fuel you produce would be carbon neutral. Of course, there are losses due to power needed to harvest, process, to produce the equipment needed to harvest and process, etc. etc. 100% can never be truly achieved.

John Goreham    January 13, 2016 - 5:47PM

In reply to by arnold (not verified)

Keep in mind that the 1998 VW Beetle is no longer made. That generation of diesel engine cannot meet current emissions standards for particulate or NOx. Its EPA-rated 38 MPG combined and 43 highway is impressive as long as diesel is cheap where you live. Diesel vehicles like the '98 Bug TDI made before emissions laws required them to be as clean as gasoline cars were also affordable.

Arnold (not verified)    January 13, 2016 - 10:55PM

In reply to by John Goreham

Diesel here in California is $2.45 while gasoline is in the low $3.

I get that 45mpg ave per tank, so not even taking the price into account it's still more efficient.

That's also driving my beetle 80-85mph on the freeway.

The VW claimed mpg is lower than what u really get in real life. And also the mpg of diesel doesn't fluctuate as much with my driving habit.

I've had a 2013 corolla where I struggled to get 30mpg ave on a tank when I drive it 80-85mph on the freeway. I'll have to really baby the gas pedal to get it up to 33mpg.

I don't know about the new 2016 corolla maybe they have direct injection w/c would increase the mpg of it but I don't think it'll be anywhere close to a diesel jetta or beetle efficient mpg.

Pat (not verified)    June 5, 2017 - 10:10PM

I've driven a diesel for the last 15 years starting with an emissions be damned Jetta A2 right through to my current uber clean Mercedes Bluetec. Any fair comparison of gasoline and diesel needs to consider real world driving; sure today's gasoline offerings get 35 mpg on a level road with cruise locked at 50 mph but unless your happy leading a convoy behind you what happens to this mileage if you knock it up a notch. Here in Canada I'm averaging 125 kph (78 mph) in my V6 E350 with a consumption of 7.6 L per 100 km (31 mpg). I challenge you to report out on the Toyota under the same conditions. (Yes I do need to spend a few pennies per litre for DEF to get my squeaky clean exhaust.)

John Goreham    June 6, 2017 - 12:45PM

Pat, thank you offering your first-hand positive experiences. Diesels do offer great drivability and highway mileage. I can't comment on a modern US-spec Mercedes diesel's comparability to the Corolla because Mercedes has no 2017 model year diesel cars for sale. Mercedes is presently under investigation for cheating on emissions in both the US and German market: I did recently test a modern diesel-equipped Jaguar XF 20D (similar to BMW 3 Series). My carefully-recorded primarily highway mileage, with as much cruise control I could use (mostly in NY state where the speed limit is 55 MPH) was 37 MPG. The diesel has the same performance as a Honda Accord base model or Lexus ES 300h. I carefully compare the green credibility and comment on the drivability of that car in the review. This week I have a Honda Civic 1.5-liter turbo gasoline version. It is half the price of the Jag, has better driveability, more room, and is much faster than the Jaguar. My mileage is 37 MPG. Here is a link to the review: Our comments don't support links so you have to cut and paste.

tim smith (not verified)    October 15, 2017 - 11:41PM

This article is cherry picking numbers to make a false conclusion. First taking the average of the city and highway MPG is not a common scenario for most drivers. 2nd the way your pricing Diesel is not accurate. During the winter time in most states the price of diesel goes up to about the same cost as premium gas. During the summer it falls to almost the same cost as regular gas. This is due to it being similar to heating oil or kerosene. Next a Corolla Eco is about 500lb lighter than a Civic and a larger car. So the playing field is not fair here either. I also find that the current EPA ratings are more conservative with Diesel cars. I have owned a Jetta TDI and could get real world MPG of 50-52 on the freeway at 70mph. I have a e350 Bluetec and its a 4100lb that can get 40-43mpg cruising at the same speed. This idea and conclusion has too many variables that your cherry picking. The cruze should get a weight handicap and play around with the numbers and you can make any conclusion you want. Top gear uk took a prius on their race track driving by a race car driver. Jeremy clarkson followed in a M3 BMW cira 2013 or so. They did this to see what car got better MPG.. surprise the M3 won. The bottom line is any diesel car will get about 30% better MPG than a gas car. Your math on the cost of diesel being higher is off.

John Goreham    October 16, 2017 - 2:59PM

In reply to by tim smith (not verified)

Hi Tim,
Thanks very much for your comment on this four-year-old article. Since it was written, we have learned that VW cheated with its diesels and polluted the environment at up to 40X the levels of gasoline engines. The New 2018 Civic has the same fuel costs as the only other affordable diesel car in its class (Chevy Cruze) and is dramatically faster. Mercedes has pulled all its diesels off the U.S. market. Thanks for checking in.

Gaetano (not verified)    March 10, 2018 - 10:10PM

What on Earth have you guys been smoking. Diesel technology is intrinsically more efficient than Petrol - roughly 20% more efficient in fact. On top of that, with particle filters, Diesel is actually also cleaner than Petrol.

Of course the Dieselgate does not help making the case but bringing the emissions in line with the specifications has not dramatically affected the fuel economy has it? worst case the performance might have been affected. Where are you getting your information from?

John Goreham    March 12, 2018 - 11:05AM

We get all of our mileage information from two sources. The automobile manufacturers themselves and the U.S. Environmental Protection Agency. Diesel vehicles, those very few left in production not in trucks, do not produce less CO2 or oxides of nitrogen than gasoline cars and the data is easily available at Look up any given model and see the second tab for emissions data based on testing. As far as I know, none of us smoke. Should we apologize for bringing truth to the debate?