SAN DIEGO – With its "cat-like reflexes" and segment-up interior materials, the original Honda Fit subcompact was an almost instant success when it was brought to the U.S. from Japan in 2006.

Sales started strong and remained so for much of the first-gen's run, peaking at 79,794 deliveries in 2008, WardsAuto data shows.

But, as happens to so many foreign cars brought to the States, the Fit got American-ized in the name of progress, growing bigger and heavier in its second generation.

Now with the third generation, on sale in the U.S. April 14, the Fit returns to its roots, with the fling-ability of the first-gen model and a roomy, well-appointed cabin, minus a couple missteps.

Perhaps the biggest win for Honda in the competitive group, which includes the segment-leading Nissan Versa Note, Ford's Fiesta and five other models, is a class-leading 36 mpg (6.5 L/100 km) fuel-economy average, estimated for LX grades equipped with a new continuously variable transmission, and up from 31 mpg (7.6 L/100 km) in the outgoing '13 model.

The new CVT, 14% lighter and with a 14% wider ratio range than the outgoing Fit's 5-speed automatic, helps Honda achieve the new peak, as does the addition of direct injection to the car's 1.5L 4-cyl. gasoline engine.

Also helping improve fuel economy is the introduction of variable timing control, which adjusts intake-cam phasing to retard valve timing at lower engine speeds; a 27% lighter crankshaft, with four instead of eight counterweights; and an all-composite intake manifold.

Fuel-economy improvements also come thanks to a 44-lb. (20.0-kg) lighter body, with 27% ultra-high-strength steel content.

However, despite all the weight-saving measures, the new Fit still is slightly heavier than its predecessor by 10-20 lbs. (4.5-9.1 kg).

WardsAuto climbed behind the wheel of two '15 Fits here in late March: a fully-loaded EX-L grade with navigation and a CVT, as well as a Fit LX with a manual.

The Fit EX-L's engine droned under hard acceleration, such as when entering a freeway on-ramp. That's not out of character for many B-cars, especially one with a maximum 130 hp, so it's only a small demerit.

In cruising and less-aggressive acceleration the 1.5L is quiet, no doubt thanks to increased use of sound insulation, in the roof, floor, doors, center console and instrument panel, as well as tighter construction that makes for better seals.

Honda makes one of the best CVTs we've tested, evident in back-to-back drives with the Fit and a Versa Note. While the Nissan B-car's CVT struggles to find the appropriate "gear," the Honda CVT always is perfectly matched to engine speed.

A 6-speed manual replaces a 5MT in the outgoing Fit. While it's improved, thanks to the added gear, closely spaced 3rd-6th gears, a 2nd-gear synchronizer ring and a 25% reduction in shift-cable sliding resistance, ergonomically the 6MT disappoints. Rows are long between gears and the shift lever's an inch too short.

Ride and handling again is a Fit strength.

By shifting more weight to the back, with a 61/39 split for CVT models vs. a 64/36 split in '13 Fits with a 5AT, the new Honda suddenly feels like its old nimble self.

The automaker keeps the outgoing Fit's strut-front and torsion-beam rear suspension setup but redesigns each for improved comfort. New blow-off valves added in the front and rear decrease damping force at higher speeds.

Steering feel is perfect: direct and heavy, but not so much that the wheel puts up a fight.

Like most Hondas, the Fit exceeds its fuel-economy estimates, with the EX-L returning 38 mpg (6.2 L/100 km) in mixed driving here, and the LX achieving 44 mpg (5.3 L/100 km) over an almost-all-freeway route.