Honda Car Forum


 

Go Back   Honda Car Forum - Accord Parts Civic Tuning Acura Racing > Honda Acura > Acura

Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 09 Apr 2004, 07:26 pm
Steve W.
Guest
 
Posts: n/a
Default Re: V-TEC/Non-V-TEC?

"M C" <mcunix@swbell.net> wrote in message
news:106mkgcb8hdi616@corp.supernews.com...
> >
> > Your explanations are very confusing. In this post, you make it

sound as
> if
> > VTEC can change the valve timing continuously. The cam has only two
> > profiles and it switches between the two when the engine deems it

needed.
> > It rides on two for economy and rides on the third one (locking all

three
> > together) for performance. As far as I understand, a non-VTEC

engine
> can't
> > really be adjusted, the profile would have to be ground on the cam.

You
> > make it sound as if adjusting the valves will give you a different

cam
> > profile to adjust the power band.
> >
> > Also, as I understand it, the engine uses different length runners

to help
> > boost torque at low engine speeds and shorter runners to boost the

top
> end.
> > Once the engine reaches a certain speed, the runners are activated

(I
> > believe it's butterfly valves) and the short runners come into play.
> >
> > -Bruce
> >
> >

>
> I knew about VTEC for a long time but never really read about it. I

think it
> is a brilliant design for getting the best of 2 worlds of valve

timing. I do
> wonder a about the reliability issue. More parts means more stuff to

wear
> out and fail. Also, the high RPM lobe actuates double duty for the

other 2
> when it is used. I'm sure honda accounted for this with extra lube if
> needed. Also, most cars don't run at high RPM all the time. Still, I

think
> this is an awsome technology and doubtless increases preformance and
> usability. Does any other maker use similar technology?
>
>

Considering how long this technology has been in use I wonder why Honda
claims it as theirs? The Corliss valves used on old steam engines was a
mechanically controlled variable valve system that varied valve action
based on engine speed, that was in 19th century.


Reply With Quote
  #2 (permalink)  
Old 10 Apr 2004, 03:47 am
George Macdonald
Guest
 
Posts: n/a
Default Re: V-TEC/Non-V-TEC?

On Fri, 9 Apr 2004 20:26:01 -0400, "Steve W." <me@homer.org> wrote:

>"M C" <mcunix@swbell.net> wrote in message
>news:106mkgcb8hdi616@corp.supernews.com...
>> >
>> > Your explanations are very confusing. In this post, you make it

>sound as
>> if
>> > VTEC can change the valve timing continuously. The cam has only two
>> > profiles and it switches between the two when the engine deems it

>needed.
>> > It rides on two for economy and rides on the third one (locking all

>three
>> > together) for performance. As far as I understand, a non-VTEC

>engine
>> can't
>> > really be adjusted, the profile would have to be ground on the cam.

>You
>> > make it sound as if adjusting the valves will give you a different

>cam
>> > profile to adjust the power band.
>> >
>> > Also, as I understand it, the engine uses different length runners

>to help
>> > boost torque at low engine speeds and shorter runners to boost the

>top
>> end.
>> > Once the engine reaches a certain speed, the runners are activated

>(I
>> > believe it's butterfly valves) and the short runners come into play.
>> >
>> > -Bruce
>> >
>> >

>>
>> I knew about VTEC for a long time but never really read about it. I

>think it
>> is a brilliant design for getting the best of 2 worlds of valve

>timing. I do
>> wonder a about the reliability issue. More parts means more stuff to

>wear
>> out and fail. Also, the high RPM lobe actuates double duty for the

>other 2
>> when it is used. I'm sure honda accounted for this with extra lube if
>> needed. Also, most cars don't run at high RPM all the time. Still, I

>think
>> this is an awsome technology and doubtless increases preformance and
>> usability. Does any other maker use similar technology?
>>
>>

>Considering how long this technology has been in use I wonder why Honda
>claims it as theirs? The Corliss valves used on old steam engines was a
>mechanically controlled variable valve system that varied valve action
>based on engine speed, that was in 19th century.


Hardly the same "technology" as I see it. In a steam engine, the "intake"
valve stays open on the power stroke so, in fact, varying the valve open
time is a method for controlling the duration of the power stroke and
therefore speed of the engine... not the contrary. Those are also rotary
valves which do not need any variation in "lift" amplitude.

I'm not sure what Honda actually claims nor what similar automotive systems
might have preceded their system but theirs was certainly innovative when
first introduced... in F1 IIRC.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 01:57 pm.


Attribution:
Honda News | Autoblog
Powered by Yahoo Answers




Powered by vBulletin®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.6.0 PL2 © 2011, Crawlability, Inc.
HondaCarForum.com is not affiliated with Honda Motor Company in any way. Honda Motor Company does not sponsor, support, or endorse HondaCarForum.com in any way. Copyright/trademark/sales mark infringements are not intended or implied.