If you thought strict new miles-per-gallon rules would sap cars of horsepower and heft, you were wrong — at least so far.

A recent report by the EPA shows that cars were just about as powerful and heavy as ever in the 2013 model year, the first year of the federal corporate average fuel economy standards that double to a nominal average of 54.5 mpg in the 2025 model year.

On average, 2013 model cars and light trucks offered in the United States weighed 4,041 pounds, up 64 pounds from 2012 and essentially unchanged from a decade earlier. They also put out an average 230 hp, tying a record set by 2011 models and beating 2003 models by 31 hp.

And yet, average combined city/highway fuel economy for 2013 models was 24 mpg, up 3 miles from 2008, reflecting the rapid adoption of technologies that squeeze more energy out of a gallon of gasoline.

The share of light vehicles with turbochargers, for instance, was nearly five times as high as in 2008 as automakers such as Ford Motor Co. and Volkswagen AG have bet that customers will tolerate smaller engines if they can summon some extra thrust as needed.

Here's a look at some of the trends noted in the EPA report.