Quote:
Originally Posted by syr74
So a 3.8L V8 would absolutely be heavier than a compable, in terms of design and tech, 3.8L V6? This simply isn't true as an absolute by an means, there are far too many other variables for anybody to make such a broad, sweeping statement.
All the usual suspects predicted the same thing once before, and they were wrong then too.
A greater number of cylinders doesn't inherently increase fuel consumption, displacement does. In fact, while this too is an issue far too complicated to paint with simple absolutes, there are more than a few arguments for a greater number of cylinders...within reason.....increasing fuel economy given similar displacement. Part of Ford's reasoning for the Triton V10 series of engine was that greater control over the combustion process would allow a 6.8L V10 to knock down better fuel economy and emissions than a comparable 6.8L V8.
In the end, you are still missing the point. There is absolutely no reason why a 3.8L V8 wouldn't knock down fuel economy on par with a technologically similar 3.8L V6 all else being reasonably equal. Engines are changing, and they will be getting smaller on average with a question, but the best run and ultimately most profitable companies are going to be those who figure out how to give the consumer what they both want and need in one package.
And to that end, it will likely be the companies who figure out the beneficial little incedentals, like the reality that there is no reason why a planned 3.8L GTDi V8 wouldn't work just as well as a 3.8L GTDi V6, who will win the day.
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The V8 will have
- a heavier block (might be on part with a 3.8 straight six)
- a greater total piston circumference (more friction)
- two extra rod journals and one extra main journal on its crank (more friction and weight)
- longer cam(s) with four (or eight) extra lifters and maybe rocker arms(more friction and weight)
- a bigger oil pump to keep all this lubed (greater parasitic loss)
- and probably a bigger water pump to serve the bigger, more complex cooling jacket(greater parasitic loss).
And there is a fair chance that the V6 will have greater total valve area which would reduce pumping losses relative to the 3.8 V8.
Fuel efficiency aside, a V6 will always be cheaper to build (and buy) than a V8 with the same tech (GDI, DOHC, Turbos, etc).