Wednesday, June 30, 2010

News From the ICE Wars.

I've been wondering for a while when someone was going to finally implement a direct-injection fuel system on an American pushrod V8. It appears that Chevy will be the first with a new generation pushrod SBC in the 2012 Corvette. Reports are that it will be 335 cubic inches and will develop 440 horses which is more than the current 6.2 version does. Even with the power boost fuel economy will undoubtedly improve with direct-injection plus there's equally little doubt it will be approved as an ultra-low emissions engine system. I'm guessing the 'vette version will sport a dual clutch gearbox with at least 8 speeds which will maximize both performance and fuel economy. With such a drivetrain the 'vette might break past 30mpg out on the slab.

The eight speed gearboxes proliferating on furrin' iron are proving to be both popular and quite useful. This large number of gears might seem like overkill but they provide a much greater overall gear spread and there are only upsides to that circumstance. Eight speed trannies have allowed such as Bimmer, Audi, and Mercedes to achieve sub-five second 0-60 times with power levels that previously would not have resulted in such impressive acceleration even with six-speeds. They can use really low final drive ratios and deep low transmission ratios for sparkling performance and still have reasonable steps up toward the .50, and even higher, top gear ratios that enhance economy.

In fact I can hardly think of any engine size that would not benefit from such transmissions or even ones with 9 or 10 gear splits. That seems like even more overkill but would result in gearing spreads that are not compromised at either end of the spectrum. Dual clutch semi-autos are turning out to be a fairly reliable and very adaptable answer to many thorny problems. As Audi and Merc have shown Diesels in particular have proven very effective users of high numbers of gear splits. No surprise there, just ask a trucker, but only in the past few years have the technical issues with such multi-geared trannies been largely solved.

Dual-clutch "manual" boxes have proven much more amenable to high numbers of gear splits because they are not dependent on multiple planetary gearsets and ultra-complex power robbing hydraulic systems of conventional automatics to go about their business. They are complex devices no doubt but less so than regular automatics and they do not suffer from torque-converter losses. Plus they can be used in user transparent auto mode or they can be manually shifted for more sporting driving. All in all these multi-speed boxes, and direct injection, are important arrows in the quiver of the not so late and not yet unlamented ICE.

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