Quote:
Originally Posted by CmicasatheGreat
As for the Vette's 16/26... from 430HP... 40 more than Porsche... well I think I just made my point... "Imagine if Chevy decides to go ahead and direct inject the LS3... milage would about 20/29.. power would be 470HP+
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DI would make a difference to be sure, but it's pretty unlikely it would be that much. First, as engines get larger the percentage improvement you see from improvements like this typically falls at least a little. The other issue is that 2-valve engines are pretty unlikely to respond as well to direct injection as are 4-valve engines, particularly where VVT is involved, with the possible exception of hybrid designs like the one Lexus employs where PFI and DI are both used. I say this because there are still some low rpm performance issues with DI and the improved port velocity a 4-valve engine will see, not to mention the more finite degree of valvetrain control offered by a DOHC engine, again particularly where VVT is involved, is likewise almost certain to do a better job here. The final issue here is that the light and aerodynamic Vette is already pretty efficient, particularly once you take the taller gearing and broad torque curve into consideration. It is, unfortunately, difficult to imporve upon the things you already do well.
Personally, I would look for something like a ~10% improvement in power and a ~5% improvement in fuel economy (city economy could potentially not improve at all) in the LS V8 with the addition of direct injection giving us something more like 17/27 with a 470-475hp rating. Still very good, but not quite a 500hp 30mpg car.
Just my two cents.