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jeepers 03-14-2001 03:55 PM

Re: Are Super Valves Headed for Motorcycles?
last year Navistar ran Pikes Peak with a "camless" engine. As stated previously, the problem seems to be in the higher rpm area. Hey Honda, let us know what you're doing about this

Grappelli 03-14-2001 06:30 PM

Re: Are Super Valves Headed for Motorcycles?
Of course the other problem is the sheer size of the things. They ain't small, and the likelyhood is they'll remain a decent size. Less of a problem in a car......

kevhog 03-14-2001 07:31 PM

Re: Are Super Valves Headed for Motorcycles?
I saw these things on a Speedvision show a while back, some mad scientist sort of stuff they were making fun of. None the less, it worked, it was loud as hell!, and according to the designer/engineer it could "theoretically" rev as high as he wanted it to. His were completely electric, and they were very, very loud. If I remeber correctly, he had it on a small Ford motor, a 2.3 pinto motor or something, and it had no oil on top of the motor. Kind of weird, but it appeared to work.

MrDeadeye 03-14-2001 10:26 PM

Re: Are Super Valves Headed for Motorcycles?
I wonder if your bike will stall during lightning storms? ;)

RobGixxer750 03-15-2001 03:32 AM

Damn, wish I knew all that off the top of my head! (nt)

hoyt 03-15-2001 03:59 AM

Re: Are Super Valves Headed for Motorcycles?
Diesels run on compression ignition so there is no spark to advance. Engine speed is thus limited to the speed at which the fuel can burn, generally around 4500 rpm for a car sized engine. As stated above, the main purpose for the camless engine is emission control.

Lincoln 03-15-2001 04:26 AM

Re: Two Stroke Fever!!!
ain't it the truth? the more complicated 4strokes become, the more 2strokes look like a brilliant idea.

BBD_Racing 03-15-2001 04:43 AM

Re: Two Stroke Fever!!!
Direct injection 2-strokes are anything BUT simple. Why do you think we haven't seen them yet?

Complexity in one area sometimes exists to create simplicity in another. Look at an old fashioned ignition system: distributor shaft, rotor, cap, condenser, points. All of these things are failure prone (except the shaft). Look at an advanced electionic system: crank trigger and a "black box." Seems simpler, but in fact, the "black box" has dozens of components and thousands of lines of software code. Still, it is far more effective and reliable.

BBD_Racing 03-15-2001 04:54 AM

Re: Are Super Valves Headed for Motorcycles?
Good analysis, Dan. An important thing to remember is that F1 engine lifespan makes ducati's WSB engines seem ultra reliable. An F1 team will go through an engine in qualifying alone. One team's F1 engine budget is larger than the whole GP industry. When Honda got out of F1 ten years ago, they spent $100 million per year. Costs have increased dramatically since then.

Hence, your observation that we have plenty of power capability as is is significant. On my way to work this morning, I was thinking about brakes vs engines. Any sportbike can stop much faster than it can accelerate. Much of this discrepancy is due to an inability to apply the power the engine has available.

This is the most significant area of improvement we will see in the next generation of sportbikes.

As for your thoughts on overlap, you are right, but there is more. High overlap at low RPM is kindof like a big valve, high lift and huge carb at low rpm. The engine makes less power and runs rougher. Variable valve timing (like my Pathfinder has) allows high torque down low and high hp up high and smooth running everywhere.

banda 03-15-2001 04:59 AM

Re: Are Super Valves Headed for Motorcycles?
Your last point about the valve overlap is very interesting. I believe that Toyota's newest engines (used on the ECHO and Prius) have zero degrees of valve overlap at idle, but the VVT-i system increases that valve overlap at higher RPMs depending on the engine speed, throttle position, and a host of other variables to deliver more power. That makes them clean, and powerful.

Actually the Honda VTEC system is quite a bit more exotic than the Toyota VVT-i, making use of two very different cam profiles changed at a set engine speed. That's above and beyond what would be required to simply change the valve overlap.

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