AUBURN HILLS, MI – The stalwart Jeep Wrangler’s next hurdle to clear is to boost fuel economy without alienating its fervid customer base, a task executives say is easier said than done.

A diesel powertrain is expected in the next-generation Wrangler, Jeep’s top executive confirmed to WardsAuto earlier this year. Still, even with that and the new option of the fuel-saving 3.6L Pentastar V-6, fuel efficiency is a challenge because the bulky Wrangler can weigh more than 1,000 lbs. (454 kg) than the Grand Cherokee, the next-largest vehicle in Jeep’s lineup.

Designers are looking for ways to make the Wrangler more aerodynamic while maintaining the “Jeepness” of the vehicle, lead designer Mark Allen tells WardsAuto at a backgrounder at the auto maker’s headquarters here.

Aerodynamics has been key to increasing the fuel efficiency of the new-for-’14 Grand Cherokee and is expected to be emphasized heavily when the midsize Cherokee is unveiled this week at the New York auto show.

But designers can’t make a rounded-off Wrangler, in production longer than Chrysler has owned the brand, without upsetting the SUV’s fans.

“The TJ (-generation Wrangler, produced between 1996 and 2006) was the first Wrangler that went in the wind tunnel, and it was much slicker than the outgoing YJ,” Allen says. “When we did the JK series, that’s when it got (aerodynamics) in plain view in the windshield, the A-pillars got much rounder.

“We try to hide that stuff, not have it be at the forefront. You’ll see more and more of that.”

Current-generation Wranglers also have air dams resembling a skid plate on the undercarriage. The dams increase air flow, Allen notes.

The Wrangler and other future Jeeps may employ fuel-saving tricks seen on the new Grand Cherokee: removable front air vents, grille shutters and rear spoilers. Automatic air suspension, first used on the ’13 Ram 1500, now is featured on the Grand Cherokee and could migrate to other vehicles in the stable.

“We’re getting quite clever with some things,” Allen says. “We’re using the rear spoiler off the SRT Viper, which was a little longer and more efficient. We’re going to keep tuning every product that we have for fuel economy.”

Designers and engineers here showcase a range of modified Wranglers for the brand’s annual Easter Safari in Moab, UT. Some of the SUVs shed hundreds of pounds of sheet metal, another trick that could be employed in future iterations of the Wrangler.

The next-generation Wrangler is expected to debut as a ’15 model.

Expect to see Jeep’s heritage played up in future vehicles, Allen says. “Since 1941” first appeared stamped into the current Wrangler’s passenger grab bar, and the phrase is emblazoned on the steering wheel of the new Grand Cherokee. The reference to Jeep’s birth year also is integrated into the headlights of the Grand Cherokee.

“There’s these little messages. We’re quite proud of our brand and its very humble beginnings,” Allen says.  “Today’s Wrangler – it’s obvious to me, and to Jeep people, it looks like our very first product. The lineage is clear. Not many people can do that.

“I can’t imagine putting the Model T on a Taurus,” he laughs.

afoley@wardsauto.com