I don't know much about engines...

[Howard]

I assume that your claim that doubling the number of valves slows velocity because of the increased valve area (correct term? the available flow area when valves are opened). Halving the lift should get you the same amount.

Even with 4 valves in the head, you could still create the ideal combustion chamber shape (source: http://www.theoldone.com/articles/The_Soft_Head_1999/)

 

[ShadowBlade]

Now, what it really needs is a VTEC sticker
like 8000000000HP+ right there

 

[RiDE]

Originally posted by: ShadowBlade
Now, what it really needs is a VTEC sticker
like 8000000000HP+ right there

and thats the 8000000000th time that joke has been said :laugh:

 

[Zenmervolt]

Originally posted by: Howard

Originally posted by: Zenmervolt

Originally posted by: Howard

Originally posted by: Random Variable
I read an article somewhere about moving to electronic actuators or something.

Impossible with current technology.

It's been done.

It is, however, incredibly expensive right now and also incredibly noisy.

ZV

Really? Link?

It was in an R&T article by Dennis Simanitis (sp?) a couple years ago. He does their technology articles and is a member of the Society of Automotive Engineers. As I recal the electromagnetic valves were in lab testing on experimental engines.

ZV

 

[Zenmervolt]

Originally posted by: Howard
I assume that your claim that doubling the number of valves slows velocity because of the increased valve area (correct term? the available flow area when valves are opened). Halving the lift should get you the same amount.

Even with 4 valves in the head, you could still create the ideal combustion chamber shape (source: http://www.theoldone.com/articles/The_Soft_Head_1999/)

Yes you can get a very close approximation of it (the realities of how the valves themselves have to be shaped mean that the best we can come is a close approximation), but that's still going to be slightly different than the shape of a 2-valve combustion chamber.

And yes you could achieve the same flow rate with half the lift, but then you've have the same choking issue at high RPM.

Until we have a cost-effective way of infinitely varrying lift, duration, and timing for the valves it's going to be impossible to avoid the tradeoffs associated with valvetrain design in any production-based engine. Even with the valve situation more in hand with electromagnetic actuation (or something similar) there are still other factors that influence an engine's powerband.

ZV