Preview Review: 2007 Dodge Caliber SRT4

CAR & DRIVER | TONY SWAN | PHOTOGRAPHY BY AARON KILEY - - Sequels are tricky. You could ask anyone in the movie business. Hey, the original was a hit — let’s repackage and play it again. The business plan looks like a no-brainer, but all too often it turns out to be just that, and the redux version tanks.

The original SRT4 was one of the first creations of the Chrysler Group’s Street and Racing Technology go-faster shop, a high-performance edition of the mild-mannered Dodge Neon. We referred to it as the Frankeneon in our December 2002 test, and that still sums it up. During its three-year run, the output of its 2.4-liter turbocharged and intercooled four climbed from 215 in the first edition to 230 horsepower, with even more available via the various aftermarket upgrade kits available through Mopar. It was capable of 0-to-60-mph times in the mid-five-second range and could cover a quarter-mile in just over 14 seconds, and in three years of production, Dodge sold more than 25,000 of them.

“The original program plan projected 10,000,” says Herb Helbig, SRT’s senior manager of vehicle synthesis and chassis design. “We sold two-and-a-half times that many.”

So when the Caliber replaced the Neon, an SRT4 sequel was not only an attractive business proposition, it was almost mandatory. But the Caliber is obviously not a Neon, and the differences go well beneath its daring new duds. So the sequel question is germane here. Will this SRT4 II be another hit with the tuner tribe? Or will it be another Caddyshack II.

More on that later. First, let’s take a look at the hardware.

The core of the ’07 Caliber SRT4, like its predecessor, is a 2.4-liter turbocharged and intercooled four, transversely mounted and driving the front wheels. But that’s where the likeness ends. The hurry-up Caliber is driven by a boosted version of an all-new, all-aluminum DOHC 16-valve four (the previous engine had an iron block), developed as a joint venture among DaimlerChrysler, Hyundai, and Mitsubishi, called GEMA, for Global Engine Manufacturing Alliance. It has a production facility in Dundee, Michigan, and the initial DaimlerChrysler yield is a three-engine family — 1.8, 2.0, and 2.4 liters.

The biggest of the trio was the obvious starting point for this exercise, and according to Pete Gladysz, senior manager for SRT powertrains, adapting the GEMA engine for high output didn’t require any really dramatic departures from the stock engine’s basic components. There are new Mahle pistons, designed for a lower stock compression ratio (8.6:1 versus 10.5:1), forged steel connecting rods, valves designed for higher operating temps, heftier bottom-end bearings, oil squirters to keep the con rods and pistons cool, and an external oil cooler.

That sounds like a lot, but none of it affects the engine’s basic architecture, and the block, head, crank, cams, and variable-valve-timing hardware (intake and exhaust) are all standard GEMA bits.

“The basic engine was designed with this kind of application in mind,” says Gladysz. “There wasn’t any point in doing anything with the cams, because with a turbo you don’t want really long cam events.

“Of course, the electronic scheme of the variable valve timing is much different from the production version, but that’s easy to handle with programming.”

And, of course, with boost.

With a slightly larger bore (88mm versus 87.5) and shorter stroke (97mm versus 101) compared with the old SRT4 engine, the new mill revs higher (a 6000-rpm power peak compared with 5300), but it’s the Garrett TD04 turbo that really makes the dyno spin. Air finds its way into the system via a Valeo air-to-air intercooler (about 50 percent bigger than the previous intercooler, according to Gladysz) and stock intake manifold. The fuel pump delivers higher flow, and there are bigger injectors delivering the combustibles.

The SRT4’s ECU, developed by Siemens, is a sophisticated piece of computer technology, and it governs boost and engine output over a broad range of operating parameters. But under ideal conditions, the turbo produces max boost of 16 psi, and with everything in optimum the new engine will churn 300 horsepower at 6000 rpm and 260 pound-feet of torque across an unusually broad range, from 2000 on to the horsepower peak. As with the previous SRT4, this adds up to a pretty seductive bang-for-buck story, only more so.

The turbo motor sends thrust to the front wheels via a new six-speed manual gearbox, a Getrag-Ford unit, and a Torsen II limited-slip diff. Aside from six speeds — the previous SRT4 tranny had only five — the most appealing traits of this new gearbox (which uses a shift mechanism from the manual trans used in the European diesel version of the Caliber) are a crisp feel and a positive sense of engagement, traits conspicuously absent in the garden-variety Caliber tested in this issue.

All of this, according to the SRT guys, adds up to a 0-to-60 capability of less than six seconds, and we have no reason to doubt that. The question is how much less. The Caliber SRT4 is going to weigh in substantially heavier than the old SRT4 — at least 200 pounds — but even so, with all that torque and horsepower on tap, we expect numbers in the middle of the five-second scale. And the top end, according to Helbig, will be pretty high.

“It’ll be a 150-mph car,” he says.

Historically, putting big horsepower through a front-drive system carries an inevitable consequence known as torque steer. It was part of the deal with the previous SRT4, and despite various countermeasures — equal-length half-shafts, for example — it’s going to be part of the deal with the new one.

“Torque steer is definitely something you need to manage in your design,” says Erich Heuschele, SRT’s vehicle dynamics supervisor. “Our goal is to keep torque steer about where it was with the previous car.”

All-wheel drive, an option in the regular Caliber lineup, would damp out torque steer, but the system isn’t capable of handling the turbo engine’s higher output. As you’d expect, the new hot rod’s underpinnings are upgraded to keep pace with the turbo motor’s big punch: heavier front knuckles, heavier hubs, beefier wheel bearings, higher spring rates, stiffer dampers, heavy-duty knuckles up front, heavier front and rear anti-roll bars, and a quicker ratio for the rack-and-pinion steering system.

The brakes are similarly upgraded, with bigger, 13.4-inch vented rotors in front and 11.9-inch rears. There are twin-piston calipers up front, and all the calipers are painted a jaunty go-fast red. Grip is supplied by 225/45 tires on 7.5-by-19-inch aluminum alloy wheels. The standard tire will be an all-season Goodyear RS-A, with Goodyear F1s optional.

Cosmetic licks include a revised front fascia with a deeper air dam, vented to enhance brake cooling; a functional hood scoop; extended rocker panels; rear air diffusers; and a bigger, more aggressive wing extending beyond the top of the rear hatch. This last is not mere eye candy, according to Heuschele.

“It’s very balanced aerodynamically,” he says. “We have no major lift issues.”

Inside, the SRT4 is distinguished by a leather-wrapped steering wheel with simulated-carbon-fiber accents, a silver finish on the instrument panel, the inevitable aluminum pedal pads, and Johnson Controls bucket seats with generous thigh and torso bolsters. The seats lack the big head bolsters of the previous version, a welcome update.

With the on-sale date still about a year away, the SRT boys are reticent about possible “stage” kits, other than to admit there will be one or more, and that a bigger turbo will be part of the plan. Over 5200 owners of first-gen SRT4s opted for stage kits, so like the SRT4 renewal itself, it’s a business opportunity the company can’t ignore. As for the possibility of renewing the ACR (American Club Racing) package, Helbig will admit only that it’s “a very good question.”

Which brings us back to the sequel issue. The SRT gang won’t say so, but the Caliber doesn’t look like a candidate for racing preparation. Although the static ride height is a half-inch lower than the standard Caliber’s, it still rides higher than the Neon. That, plus its high profile, adds up to a high center of gravity, and the higher curb weight doesn’t help, either. Looking at it from the street-machine perspective, there’s also a question, in our minds at least, whether the blocky styling is going to seduce the tuner crowd.

On the other hand, the SRT team sees the body style as an opportunity to expand the car’s market appeal to mid-’20s guys with families. And this much is certain: If Dodge makes good on its plan to keep prices low, and the new SRT4 rolls into showrooms with a base of about $22,000, it will still be an absolutely unbeatable performance buy.

2007 DODGE CALIBER SRT4

Vehicle type: front-engine, front-wheel-drive, 5-passenger, 5-door wagon
Estimated base price: $22,000
Engine type: turbocharged and intercooled DOHC 16-valve inline-4, aluminum block and head, port fuel injection

Displacement: 144 cu in, 2360cc
Power (SAE net): 300 bhp @ 6000 rpm
Torque (SAE net): 260 lb-ft @ 2000 rpm

Transmission: 6-speed manual
Wheelbase: 103.7 in
Length/width/height: 173.8/68.8/59.9 in
Curb weight: 3200 lb
Performance ratings (C/D est):
Zero to 60 mph: 5.5 sec
Standing ¼-mile: 14.1 sec
Projected fuel economy (mfr’s est):
EPA city driving: 22 mpg
EPA highway driving: 28 mpg