Re: [ST] Drive by Wire

[Matthew Heyer <matthewheyer@xxxxxxxxx>]

I have VTEC in both my Honda Accord and Acura MDX.  I don't really notice it too much on the MDX, but the thing makes 265 hp anyway.  It appears to be a more refined version of it too (the MDX is a 2005 - the Accord a 1996). On the Accord (it's a manual shift too), you can definitely feel changes in power at distinct RPM.  It is all supposedly done to maximize power at high RPM when you want it, and maximize power and fuel efficiency at lower RPM.  The thing that I have heard about the implementation in motorcycles (specifically the VFR) is that is is not a true VTEC - just more valves opening at a certain RPM (as pointed out below).  Most reviewers of the motorcycle state it can be weird/bad when you are riding and moving the RPM just above/below that RPM point - makes the power sort of come and go.  Easy solution is to change gears and either stay above or below.  And as stated below as well, some people like the feeling of the power hit - some find it just lacks power
 underneath it.
 
Matt Heyer


----- Original Message ----
From: Dan Wetherington <dew@xxxxxxxxxxxxx>
To: ST@xxxxxxxxxxxxxx
Sent: Wednesday, May 31, 2006 7:43:23 AM
Subject: Re: [ST] Drive by Wire


I think it is a great idea when implemented properly (Honda cars, BMW
has some sort of VVT setup).  However, the problem with VTEC in the VFR
is that its a GO-NO GO situation.  The setup opens a second set of
valves at a specific RPM, giving the same effect you get from hitting
the powerband on older race bikes (its actually hard to describe, but
that kind of gives you the idea).  Some people don't mind it, even like
it.  However, if they could make the valve timing seamlessly adjustable,
it would be much more efficient.

Dan

Dan Wetherington
Senior Technician I
Packer Engineering
dew@xxxxxxxxxxxxx
(630) 577-2055 (direct dial)
(630) 505-5722 (operator)
>>> BrettWilson21@xxxxxxx 05/31/06 1:10 AM >>>
Its certainly an interesting time to be around to witness this
development.

I've never driven a car with variable valve timing so perhaps someone
can 
enlighten me as to whether its a noticeable thing or not and how this
may work or 
not when properly developed for a mtorcycle?

Brett.
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