The Chevrolet Hhr is based on GM’s front-wheel drive Delta platform, which underpins a score of vehicles including the Chevrolet Cobalt, and the former Saturn Ion, Saturn Astra and Pontiac G5. Inside, there is seating for five and a flexible cargo management system that includes flat-folding rear and front passenger seatbacks, various storage bins, and a height-adjustable cargo panel. An LT Panel version is also offered and intended for use as a city delivery vehicle.
In its first year of sale, the HHR came powered in its base form by a 143 horsepower 2.2-liter four-cylinder engine, with a 2.4-liter version available on higher trim levels that rates in 172 horsepower. For 2007 output from the engines were bumped up to 149 horsepower and 175 horsepower, respectively. New features for 2008 added to the HHR's safety, including stability control, a tire pressure monitoring and OnStar. A new SS performance with a 2.0-liter turbocharged engine was added to the lineup for 2009. This particular model came with a 260 horsepower and 260 pound-feet output rating and thanks to driver-selectable performance features, such as the no-lift shift, the HHR SS achieved 0-60 mph performance in 6.3 seconds and covered the quarter-mile in 14.8 seconds at 98.5 mph. Variable valve timing was also added to the base 2.2-liter mill, and this saw output increase to 155 horsepower, up from 149 horses the previous year.
There were no major changes introduced for the 2010 Chevrolet HHR. The most efficient model is the 2.2-liter manual, which returns 22 mpg in the city and 32 mpg on the highway. The SS model is surprisingly efficient, returning 21 mpg in the city and 29 mpg on the highway.