Based on what we see in the cabin of the Dart models shown at Detroit, cabin appointments appear to overcompensate for the Caliber’s woes. But with the new Tigershark engines that are standard under the hood of all Dart models (2.0-liter, or 2.4-liter in the R/T, although a Fiat 1.4T is optional) what of noise, vibration, and harshness? That’s what we asked Dart chief engineer Mike Merlo at the show this week. And if the revised Charger and Journey aren’t evidence enough, it sounds like much has changed in the way that Chrysler engineers vehicles.
Here are six reasons why the Dart will be much more refined than former Chrysler small cars—as well as, possibly, many other cars in its class:
1) A Better World (Engine). The new 2.0-liter and 2.4-liter Tigershark in-line four-cylinder engines are derived from what was formerly called the World Engine. And while they share some block architecture and other pieces, there are actually few carry-over parts, the automaker insists. “The displacement is still basically the same, but we've changed bore and stroke a bit, in an effort to improve the overall noise and vibration characteristics,” said Merlo. That also includes an all-new forged crankshaft, said Menlo, and they’ve changed the bearing locations for better stability (and less vibration).
2) Moving Exhaust Noise Away From The Driver. The most important change, perhaps, is that engineers rotated the way the engine is installed and mounted 180 degrees, to put the intake in front. “By positioning the exhaust in the front side of the engine, we're really moving most of the noise away from the passenger compartment,” explained Merlo.
3) More Noise Treatment Everywhere Else. “And we’ve changed the head around dramatically, obviously, because of the front exhaust and rear intake,” said Merlo. To match the new orientation, Chrysler designed a new, long-runner intake manifolds for these engines, with various noise treatments and a bi-metal noise and heat shields for both intake and exhaust.
4) Better, Smoother Breathing. The 2.0-liter version that the 2013 Dodge Dart SE, SXT, Rallye, and Limited models will come with standard maintains the same basic DOHC arrangement that the World Engine had, but with some improvements for upcoming emissions regulations. The 2.4-liter is a different story; it’s getting an all-new cylinder head, along with a MultiAir2 version of Fiat’s variable valve timing and lift system.