Has vtec had its day?
10-11-2010, 06:52 AM
#52
What, sliding throttle? Goooogle "Motorcycle Carburettors"
Still causes more turbulence than no throttle at all.
I've always wondered HTH one copes with idle etc revs on an inlet valve; it must be barely cracking the seal.
Also, since grease monkeys CBA to adjust the tappet clearances properly on a regular engine...
Still causes more turbulence than no throttle at all.
I've always wondered HTH one copes with idle etc revs on an inlet valve; it must be barely cracking the seal.
Also, since grease monkeys CBA to adjust the tappet clearances properly on a regular engine...
10-11-2010, 12:13 PM
#53
Originally Posted by Polemicist,Oct 5 2010, 04:26 PM
It's all yesterday's technology.
My money's on the development of Tesla's (as in Nikola Tesla and not the car manufacturer...) magnetic resonant transmission of electricity. That means electric cars without batteries or onboard generation, receiving power from nuclear reactors 'somewhere'...
My money's on the development of Tesla's (as in Nikola Tesla and not the car manufacturer...) magnetic resonant transmission of electricity. That means electric cars without batteries or onboard generation, receiving power from nuclear reactors 'somewhere'...
Job Done.
10-11-2010, 12:23 PM
#55
Many clever touches; they've 'reversed' the exhaust drive to get a narrow valve angle for economy and packaging the bellcrany and plug cylinder were quite fun.
Shame it's all come to nowt...
Shame it's all come to nowt...
10-11-2010, 12:50 PM
#56
Registered User
Nick, you're right it is pretty heavy reading but I get the general gist of how it's working. Would love to have a detailed look around one on a bench.
As for the slide throttle, not far off from my guess. Can see one main issue with that type of valve. To get low turbulence you'd need to have very tight tolerances between the slide and housing. At the same time the interface between the slide and housing would have a relatively large surface area. Finally in modern engines with EGR/PCV systems you will have some combustion gas coming past that plate.
Sounds like a perfect recipe for sticking valves. I have no experience of this valve but that'd be my guess of one of the main considerations. For those in the know am I even close?
Butterfly types the contact area between the housing and the valve is very small and it's easy to generate enough to torque to overcome any build up and rotate the shaft backwards and forwards
As for the slide throttle, not far off from my guess. Can see one main issue with that type of valve. To get low turbulence you'd need to have very tight tolerances between the slide and housing. At the same time the interface between the slide and housing would have a relatively large surface area. Finally in modern engines with EGR/PCV systems you will have some combustion gas coming past that plate.
Sounds like a perfect recipe for sticking valves. I have no experience of this valve but that'd be my guess of one of the main considerations. For those in the know am I even close?
Butterfly types the contact area between the housing and the valve is very small and it's easy to generate enough to torque to overcome any build up and rotate the shaft backwards and forwards
10-11-2010, 02:49 PM
#57
Registered User
I'm not sure what you just said it's quite complicated and its late 
I did however find this example of what I mean...
http://www.sevenbuilder.com/id/53/lumeniti...throttle-bodies
Does that make more sense now or have I confused things further?
I did however find this example of what I mean...
http://www.sevenbuilder.com/id/53/lumeniti...throttle-bodies
Does that make more sense now or have I confused things further?
10-12-2010, 01:42 AM
#58
The Thames Barrier version!
Mototcycles use sliders because they're not drawn shut by the airflow, so stay where they're put to reduce wrist strain.
Barrels can be, like Ben say, rather high maintenance & only have an advantage at full-throttle. Which isn't a problem if you only want them for idle control.
Mototcycles use sliders because they're not drawn shut by the airflow, so stay where they're put to reduce wrist strain.
Barrels can be, like Ben say, rather high maintenance & only have an advantage at full-throttle. Which isn't a problem if you only want them for idle control.
10-12-2010, 02:10 AM
#59
Thread
Thread Starter
Forum
Replies
Last Post