Why are you so angry? We're just having a discussion.

I think the mistake you're making is where you say we're "debating." I'm not debating anything. I'm just making a statement, that's pretty well understood. No, I don't have time to research the issue and prove it to you. Plus, it's kind of fruitless to try and find modern vehicles that use two valves to make a comparison. Are there any manufactuers that make a two valve and four valve version of the same engine? Not today, I don't think. And are there any Jap. or Euro. manufacturers who make a 2V at all? Again, I dont' think so. I'm not saying European engines are better, but I'm saying they know how to favor fuel economy.

Plus, I don't even understand your terminology. OHV? Aren't both 2V and 4V OHV..? And pushrods don't have a lot to do with it, because you can have a 4V pushrod engine. It's really a question of 2V vs. 4V. And I don't understand your point about a 6L OHV engine? Again, I can't "prove" anything without taking a lot of time, so I pulled a few cites off the internet. Don't ask me to explain them, because I've already spent way too much time "debating" the obvious here. Thanks.

UC Irvine
http://darwin.bio.uci.edu/~sustain/g...ndhu/fuel.html

"Along the lines of the OHC engine, another modification that can be made to the engine is by having four valves per cylinder. . . . Also, a greater valve area reduces any losses that may have been incurred through pumping, and there is also an increase in compression ratio, leading to a higher thermodynamic efficiency. ...

When compared directly to a two-valve engine with the same cylinders, the four-valve engine has a five percent advantage in fuel economy. The four-valve engine has an eight percent margin in comparison with a two-valve six-cylinder engine. The increase in the compression ratio stems from the fact that the combustion chamber becomes more compact. The increase in compression ratio from 9.0 to 10.0 leads to a two percent increase in the overall economy of the vehicle.

US D.O.E.
http://www.osti.gov/energycitations/...sti_id=5543681

The multi-valve four stroke cycle engine design trend is toward increased engine power and higher fuel efficiency. While a four-valve system is the most common direction, problems occur when the valve area is widened by increasing the cylinder bore for a higher engine output. The layout for four larger valves causes the combustion chamber shape to flatten and the combustion time period to increase. In pursuit of the optimum multi-valve engine we have studied four, five, six and seven-valve per cylinder design. Performance targets and design constraints led toward the successful five-valve engine technology.

Chevron
http://www.chevron.com/products/prod.../fuel_economy/
Increasing the number of valves provides other fuel economy benefits: "...the greater valve area...reduces pumping losses, and the more compact combustion chamber geometry and central spark plug location allow an increase in compression ratio."


Companies are getting beat up on FE and emission today...and the U.S. customer still wants performance. So there is one reason a company would still produce a 2V today: cost.