The Gas Guzzler schedule, with mpg ratings and charges that haven't changed since 1991, lays out which fuel-swillers owe what to Uncle Sam.

I started thinking about the "Gas Guzzler Tax" – considerably less well known as The Energy Tax Act of 1978 – when I was driving Dodge's new Challenger SRT Hellcat last week. Unsurprisingly for a car that can burn 1.5 gallons of gas per minute at max tilt, theoretically able to empty a full tank of premium in about 13 minutes, the Hellcat will be subject to the Gas Guzzler Tax schedule when it goes on sale.

Beyond knowing that it existed, and occasionally seeing a surcharge for it listed on the specification sheet for a press car I'd been loaned, I didn't really understand how the GGT worked or was calculated.

Thankfully, the Environmental Protection Agency makes learning about the GGT (and a lot of other stuff) pretty simple. has a clearly written explanation of the tax and the tax schedule. That schedule, operating with miles-per-gallon ratings and charges that haven't changed since 1991, clearly lays out which fuel-swillers owe what to Uncle Sam. Basically, if a car's combined fuel economy rating is 22.5 mpg or higher it's off the hook ­– trucks, minivans and SUVs are all exempt from the GGT – if the rating is lower, per vehicle taxes range from $1,000 to $7,700 for the very thirstiest.

Simple, right?

There are a couple of important caveats to all this. First, the GGT is charged to the vehicle manufacturer or importer directly, not to consumers, though the cost is very often added on to the bottom-line price for you and me. That said, just because your car or truck is subject to the tax doesn't mean you'll see a line item on its window sticker.

The bigger caveat is this: Even though the mpg numbers for Highway, City and Combined fuel economy ratings that you see on a new car's window sticker come from the EPA, they are not the same figures used to calculate the GGT. Basically, the EPA uses pure laboratory testing to glean its fundamental mpg ratings, but for the purposes of window stickers, it also factors in three other testing protocols to better replicate real-world driving. However, for reasons that are not made immediately clear in the documentation (but probably with roots in some serious lobbying dollars), the GGT is factored on the lab numbers alone, which are more lenient.

As a result of this odd double-standard system, there are a whole host of cars on sale in 2014 that show ratings well below the tax standard, but aren't charged.

As a result of this odd double-standard system, there are a whole host of cars on sale for the 2014 model year that show combined ratings well below the 22.5-mpg-combined standard, yet they still aren't charged for the GGT. But which models guzzle hardest without dinging potential owners for a few extra grand of MSRP?

Combing through the EPA data, I set a standard of 18 mpg combined or worse for my list, as the total number of cars not hit by the tax and rated at 19-21 hits triple digits – they aren't that rare.

Of the 40-plus models (when variants are added in) I came up with, two in particular stand out as the very best at playing the EPA's lab game. You'll see quite a few 5.0-liter-V8-equipped Jaguar models on this list, but the 2014 XKR and XKR-S Convertibles, rated at 15/22/17, city/highway/combined, burn the most gas without paying the piper. With an equal 17-mpg-combined rating, the completely awesome Mercedes-Benz E63 AMG S 4Matic Wagon (15/21, City/Highway) is even a hair thirstier than the aged Jag.

Though there's a lot of variance in city and highway ratings, every other model that slips in under the GGT reach nets out at 18 mpg combined – a rating which, if eligible for the tax schedule, would add cost to the tune of $2,600 per model.

In addition to having the thirstiest models on this list, Mercedes and Jaguar also have the most entries. Big Benz models with the twin-turbo, 5.5-liter V8 and the seven-speed transmission are popular GGT-dodgers, though the CL550 4Matic makes the list as well (all according to plan, it seems). Jaguars fitted with the 5.0-liter supercharged V8, in several different power flavors, combine to give the brand 13 entries after figuring for variants, all making 18 mpg combined or worse.

In addition to having the thirstiest models on this list, Mercedes and Jaguar also have the most entries.

While almost every car on the list is rocking a V8 and an automated transmission of some kind (note that the "AT" references for transmission in the spreadsheet do account for some dual-clutch and automated-manual boxes), there are a few outliers. The Maserati Quattroporte S Q4 and Ghibli S Q4 both feature a turbo'd 3.0-liter V6, the smallest displacement engine of the group. Still, 404 horsepower from three liters has to come with with a fuel-economy penalty, and both Masers are a bit thirsty – 15/24/18 ratings for the QP and 15/25/18 for the Ghibli.

Meanwhile, it's fitting that the biggest-displacement engine on the list is found under the hood of some good-old-fashioned American iron. The 2014 Chevy Camaro SS displaces 6.2-liters of Red, White and Blue glory, while returning 15/24/18, city/highway/combined mpg with the six-speed automatic gearbox. It's worth noting that the supercharged ZL1 and the 7.0-liter Z/28 both get dinged for GGT.

I also find it pretty excellent that the supercharged, 5.8-liter, 662-hp Shelby GT500 is not, technically, a gas guzzler. Considering that the super Ford also has one of the best power-to-weight ratios in the country, I'd call it a very successful pony car.

If you're interested in seeing the full list of Gas Guzzler Tax escapees, you'll find it in press-release form below. Take a look, then tell us, in Comments, which of the under-the-wire cars you find most compelling.

Show full PR text
Audi RS 5 4.2L V8 7AT 16 23 18
Audi RS 5 Cabrioilet 4.2L V8 7AT 16 22 18
Bentley Continental GT 4.0L V8 8AT 15 24 18
Cadillac CTS 3.6L V6 8AT 16 24 18
Chevy Camaro SS 6.2L V8 6AT 15 24 18
Chrysler 300 AWD 5.7L V8 5AT 15 25 18
Dodge Challenger 5.7L V8 6MT 15 23 18
Dodge Challenger 5.7L V8 5AT 15 25 18
Dodge Charger AWD 5.7L V8 5AT 15 23 18
Dodge Charger 5.7L V8 5AT 15 25 18
Ford Shelby GT500 5.8L V8 6MT 15 24 18
Hyundai Equus 5.0L V8 8AT 15 23 18
Hyundai Genesis R Spec 5.0L V8 8AT 15 23 18
Jaguar F-Type V8 S 5.0L V8 8AT 16 23 18
Jaguar XF 5.0 SC / XFR / XFR-S 5.0L V8 6AT 15 23 18
Jaguar XJ SC / XJR / XJL SC / XJR LWB 5.0L V8 8AT 15 23 18
Jaguar XKR / XKR-S 5.0L V8 6AT 15 22 18
Jaguar XK Convertible 5.0L V8 6AT 16 22 18
Jaguar XKR / XKR-S Convertible 5.0L V8 6AT 15 22 17
McLaren MP4-12C Coupe / Spider 3.8L V8 7AT 15 22 18
Lexus IS F 5.0L V8 8AT 16 23 18
Lexus LS 460 AWD / LS 460 L AWD 4.6L V8 8AT 16 23 18
Maserati Ghibli S Q4 3.0L V6 8AT 15 25 18
Maserati Quattroporte S Q4 3.0L V6 8AT 15 24 18
Mercedes-Benz CL550 4Matic 4.7L V8 7AT 15 24 18
Mercedes-Benz CL63 AMG 5.5L V8 7AT 15 22 18
Mercedes-Benz CLS63 AMG 4Matic 5.5L V8 7AT 16 22 18
Mercedes-Benz CLS63 AMG S 4Matic 5.5L V8 7AT 16 22 18
Mercedes-Benz S63 AMG 4Matic 5.5L V8 7AT 15 23 18
Mercedes-Benz E63 AMG S 4Matic 5.5L V8 7AT 15 22 18
Mercedes-Benz E63 AMG S 4Matic Wagon 5.5L V8 7AT 15 21 17
Porsche Panamera Turbo / Turbo S 4.8L V8 7AT 15 24 18
Roush Stage 3 Mustang 5.0L V8 6MT 15 22 18

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    • 1 Second Ago
      Rick C.
      • 1 Year Ago
      Trucks and suvs should not be except from the GGT.
        T. C.
        • 1 Year Ago
        @Rick C.
        I think you mean "exempt."
        Bruce Lee
        • 1 Year Ago
        @Rick C.
        I agree on SUVs for sure but I'm not sure a heavy duty work truck used for hauling a lot of stuff should be penalized for being what it is.
        • 1 Year Ago
        @Rick C.
        Even if they are under the MPG threshold? Would that mean that you don't like an SUV because of symbolism?
      • 1 Year Ago
      And people complain about the skip shift eliminators in Corvettes, Mustangs and the like. Would you rather be stuck with the skip shift that can be disabled for $35.00 or the gas guzzler extortion for $1000.00+
        • 1 Year Ago
        My '97 Camaro Z28 had a skip shift feature (Computer Aided Gear Selection) that could be disabled by a simple resistor and a zip tie. Didn't know that saved me $1k...
      Justin Campanale
      • 1 Year Ago
      Why are trucks and SUVs exempt?
        T. C.
        • 1 Year Ago
        @Justin Campanale
        The rational given is that these are so-called "work" vehicles, and levying the tax on them would hurt business owners. Of course, the overwhelming majority of these big vehicles (particularly SUVs) are personal passenger cars, not commercial work trucks.
          Seyth Miersma
          • 1 Year Ago
          @T. C.
          That's true. Though, to be fair, even the EPA has a line in its explanation of GGT that sort of tacitly admits that the notion is very outdated: "Trucks, minivans, and sport utility vehicles (SUV) are not covered because these vehicle types were not widely available in 1978 and were rarely used for non-commercial purposes." ....
        • 1 Year Ago
        @Justin Campanale
        I think trucks and SUVs should only be exempt if purchased with a commercial registration. Too many people buy them for vanity.
      • 1 Year Ago
      The gas guzzler tax needs to be abolished. It doesn't do anything.
      • 1 Year Ago
      Another example of an excessively complicated taxation/regulation mechanism, contributing to a disgusting patchwork of policies designed to reduce our reliance on fossil fuels, that could and should be eliminated as part of the package deal on a carbon tax & rebate. -GGT -CAFE standards -Renewable Portfolio Standards -(Renewable) Production Tax Credits -(Renewable) Investment Tax Credits -gas tax (should just be sales tax) Any I'm missing?
        • 1 Year Ago
        A carbon tax would punish poor people who need their cars to drive to work, and let rich people off the hook.
          • 1 Year Ago
          All non-progressive taxes (sales tax, gas tax, VAT, tolls, etc) 'punish' poor people, this isn't a good argument against a carbon tax. @GoodCheer mentioned rebates, these can be claimed by low income car owners and and businesses using the cars for 'work.'
      • 1 Year Ago
      I bet you most of these 'just hits 18mpg' cars are cheaters. The EPA should retest every car that supposed just makes the cutoffs. Way too suspicious.
      T. C.
      • 1 Year Ago
      22.5 mpg?! By now, that should be much higher, at least 30-35. And SUVs, CUVs or whatever other UVs you want to talk about should be included, as almost all of those are passenger vehicles owned by individuals.
      Sergey R
      • 1 Year Ago
      I'd like to see a list of cars. I mean it's takes time to read through all this article, so I guess posting a summarizing list would be easy for readers.
        Seyth Miersma
        • 1 Year Ago
        @Sergey R
        Hey Sergey, The list is available in the article. Click on that "Show Press Release" button at the bottom of the page, and it should pop out for you. Thanks for reading. -Seyth
      D E S I G N
      • 1 Year Ago
      I just can't write this enough, that front is probably the ugliest design to have ever been implemented on a vehicle since the beginning of the automotive history. Just saying.
      • 1 Year Ago
      I find none of them compelling, precisely because of their inclusion on this list. Or really, their use of gas to begin with... Nothing this inefficient should be allowed on the road, really.
        • 1 Year Ago

        Do us all a favor and unplug your Volt and drive it off a cliff!  That is all.  :)

      • 1 Year Ago
      How is it that a V6, 8sp Caddy gets such poor mileage?
      Belinda Mills
      • 1 Year Ago
      Why oh why are truck & SUVs exempt from this tax law?
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