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As the old saying goes, “people buy power but they drive torque” and this is especially true when your engine is teamed with an automatic transmission. This fact, when combined with rising fuel prices have made many including myself portend that the modern turbodiesel rather than the hybrid is what America needs right now. Reading a piece like this comparison of a 2.5 liter gas engine and 3.0L turbodiesel you’ll see why.

Here’s an excerpt:

Maybe it’s torque that adds excitement… This is more fun; press the accelerator and this BMW just thrusts forward, usually without bothering to change down, because there’s no need and the gearbox knows it… More urge, less effort. And here’s the clincher; the engine is almost as smooth as the 325i’s. It emits hardly any diesel rattle, and it has a voice. A proper note; deep, authoritative, six-cylinderish. This is not just a great diesel. It’s a great engine… this isn’t about buying a diesel to save money and suffer pain. It’s about buying a diesel because you’ll have more fun with it.

But just as diesel prepares for its walk onstage and play up its efficiency advantage, engineers are finding ways to squeeze even more power and efficiency out of gasoline engines, and strangely enough its by mimicing certain aspects of the diesel such as direct injection and high compression ratios.

That’s what BMW is set to do with their engine line in the coming years… The VALVETRONIC technology quietly introduced in this generation of engines will soon be augmented by direct injection. The twin turbocharged engine in the 335i coupe is the first to get the technology, but it will make it into the normally aspirated engines soon…

The result:

Peak output for the new DI engine is up from 265bhp to 272bhp… the new engine has real bite and punch, feeling a touch more aggressive than today’s 330i unit despite the official figures. At this stage of the development there’s a subtle but clear change in engine note, too. It’s less of a turbine hum and a tad gruffer – put it down to the new injection system… relaxed driving in stop-start conditions would return around 40mpg – virtually the same as offered by the diesel 330d. – Autocar

It’s true what they say: competition does improve the breed…

NOTE: At this point in time its not the engines but the fuel that’s a limiting factor – both technologies require lower sulphur content than we currently have available.

This entry was posted on Monday, June 12th, 2006 at 10:54 am and is filed under BMW, hybrids, technical.