The basic 2010 Chevrolet HHRs are offered with the choice of one of two different four-cylinder engines: a 2.2-liter unit or 2.4-liter mill. A standard five-speed manual transmission or optional four-speed automatic comes with either engine on this front-wheel-drive vehicle. Additionally, a remote start feature is offered with the 2.4-liter. Last year variable valve timing was added to the base 2.2-liter mill, and this saw output increase to 155 horsepower, up from 149 horses the previous year. Fuel economy was also improved, yielding a driving range of up to 500 miles between service station stops with this more efficient engine. It should be noted that regardless of the transmission, performance isn't anything to shout about, though it's still decent for this class.
The general consensus across the board is that both of these engines aren't going to win any awards for passing or acceleration, though they remain spirited and economical. Edmunds finds the 2.4-liter engine “a worthwhile upgrade.” ConsumerGuide, on the other hand, reports that "2.4-liter models have decent around-town go, but highway passing and hill climbs can feel labored," adding that the "automatic transmission is responsive [and] quick to downshift." Reviewers agree that the performance is neither nippy nor smooth. The Detroit News remarks that “the Chevy's powertrain was unable to inspire much confidence, especially during merging and passing,” and Edmunds refers to the “lack of low-end pull and refinement from the 2.4-liter engine.”
While most of the HHR's rivals are also front-wheel drive only, Edmunds finds fault with the fact that the HHR lacks an AWD option “for enhanced foul-weather capability.”
The 2010 Chevrolet HHR SS is an impressive offering that targets performance enthusiasts. Powering the SS is a turbocharged and direct-injected 2.0-liter four-cylinder engine, which enables the HHR SS to achieve EPA-rated highway mileage of 29 mpg with the manual transmission and 28 mpg with the automatic. Driver-selectable performance features, including the “no-lift shift,” help the SS achieve 0-60 mph performance in 6.3 seconds and cover the quarter-mile in 14.8 seconds at 98.5 mph. Equipped with the manual transmission, the SS has a top speed of more than 150 mph. Non-SS versions of the 2010 HHR have a very soft suspension, and it's not very nimble for tight corners or quick maneuvers, but the HHR LT and SS models include a sport-tuned suspension that doesn't sacrifice too much ride quality. The electric power steering in the HHR is a disappointment; it's just too light and imprecise in standard versions, though the revised tuning in the SS is an improvement.
Edmunds claims this version offers “spirited performance.” Its turbocharged 2.0-liter Ecotec four-cylinder makes 260 horsepower that is channeled to the front wheels through a five-speed manual transmission. Autoblog points out that the HHR SS "packs an impressive 130 horsepower per liter," and Cars.com is happy that the turbo engine “pulls the HHR SS with satisfying strength."
Autoblog states that in the SS "the automatic loses out on power by a few dozen horses and offers a more sedate driving experience," while also recommending that you "stick to the manual so you don't miss out on the awesomeness that is the launch control and no-lift shifting." The SS gets a slicker manual gearbox, though; ConsumerGuide finds it "has smooth shift and clutch action, unlike other manual HHRs, which suffer from long throws and crude movement."
In terms of fuel economy, the 2010 Chevrolet HHR can be best described as frugal. Autoblog suggests that one should "hold off the throttle pedal a bit and you'll be able to get near 30 mpg on the highway." EPA estimates range up to 30 mpg highway with the 2.2-liter engine and manual transmission. ConsumerGuide points out that "Chevrolet recommends premium-grade gas for SS and 2.4-liter models, regular otherwise."
If you're expecting any sort of performance, the SS is the only trim that should be considered. Car and Driver notes that the HHR has “rubbery steering, bobby suspension, and imprecise control,” though it notes a “smooth ride.” ConsumerGuide states that the Chevrolet HHR is "composed overall, though the ride can get bouncy over sharp bumps," and Edmunds recommends that "it's best to maintain an easygoing pace, as the suspension and steering just can't keep up with overly aggressive driving... the electric-assisted steering is slow to respond and numb in feel, [and] the HHR exhibits a loss of straight-line stability during maximum braking." The SS version is a different beast entirely: When it comes to handling, it has “stronger braking and buttoned-down handling,” Edmunds explains.