#MpgRatings

Mazda announced on August 8th what had long been rumored. The small Japanese automaker has successfully overcome the remaining issues which held at bay mass production of gasoline compression ignition.

Essentially, Mazda’s Skyactiv-X engines, due first in the next-generation 2019 Mazda 3, is intended to bring diesel-like ignition to small, supercharged four-cylinder engines, along with diesel-like fuel economy. However, the gas-fired Skyactiv-X engines will be wildly cleaner than diesel powerplants. Mazda has said in the past that these HCCI engines will likely limit the need for continuously variable transmissions. We also learned, with Mazda’s latest pronouncement, that the company’s Skyactiv-X engines will be significantly torquier than their Skyactiv-G predecessors.

If Mazda can live up to its pronouncements — the company says the engines are “still under development and figures are subject to change” — it’ll be a win for both the environment and driving enthusiasts. And because Mazda also claims a 20-30-percent improvement in fuel efficiency, it’ll be a win for your bank account, as well.

We wanted to see exactly where Mazda’s alleged fuel savings will put Mazda’s current products on the EPA’s miles per gallon scale, so here are the results of some quick math.

With front-wheel drive, a 2.0-liter turbocharged four-cylinder engine, and a seven-speed dual-clutch transmission, the all-new 2017 Audi A4 Ultra’s EPA highway fuel economy figure is 37 miles per gallon.

Audi says, “No other luxury sedan in its competitive segment offers higher EPA-estimated city or highway mileage” than the new fuel-sipping A4, which the Environmental Protection Agency rates at 27 mpg in the city and 31 mpg combined.

The EPA scores the rear-wheel-drive BMW at 32 mpg city and 42 highway and the 330e at a combined 72 mpge equivalent. Audi presumably excluded these non-entry-level, uniquely powered models from the “competitive segment” definition.

On the heels of a stop sale order and subsequent rush to reprint Monroney stickers with correct EPA fuel economy ratings, General Motors is working on a plan to compensate buyers of the 2016 Chevrolet Traverse, GMC Acadia and Buick Enclave.

Seeking to smooth any ruffled feathers, GM expects to announce a plan to dealers and customers within the next seven days, according to Automotive News.

That assurance isn’t enough to placate some owners of the full-size crossover, as GM was slapped with a prospective class-action lawsuit on Tuesday.

Most customers purchasing a 2015 Dodge Challenger SRT Hellcat aren’t likely considering fuel economy as a reason for wanting one of the most brutal machines ever assembled. That said, the pony car is fairly efficient on the highway in comparison to more exotic fare.