Date:         Thu, 22 Aug 2002 01:58:02 +0100
Reply-To:     Clive Smith <clive.harman-smith@NTLWORLD.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Clive Smith <clive.harman-smith@NTLWORLD.COM>
Subject:      Re: Oil Weight Recommendation/ hifi
Content-Type: text/plain; charset="iso-8859-1"

----- Original Message -----
From: "mike" <mwmiller@cwnet.com>
To: "Clive Smith" <clive.harman-smith@ntlworld.com>
Sent: Wednesday, August 21, 2002 5:19 PM
Subject: Re: Oil Weight Recommendation/ hifi


> OK I'll bite.  I've been fooling with hifi for 45 years.  I always thought
> that Brit watts and US watts were the same.  What have I been missing?
>
> Mike
>

HiFi or sound systems? Traditionally, British Hi Fis and all sound systems
were rated per channel true continuous RMS Watts.
US ratings always seem to be transient or peak (2 or root 2 times) music
power rated and quoted for both channels, unless one reads the small print.
Music power (I've forgotten the acronym used, IHFM or something) is supposed
to give a 'better' measure of the power to reproduce typical music
waveforms. Doubling RMS first and then using this form of rating can make a
tradtionally quoted 25W/channel system advertisable as a 100 Watt system.
That said, we are now getting the 'consumer' disease here, certainly for car
sound systems and cheapo crap hi-fi's making true comparisons a matter of
reading the smallprint, if it exists. Much the same with gallons of petrol
(yours are smaller, making the number you get for a given volume, larger),
computer screen sizes (exageratted binnacle diagonals) etc etc.

Just the way of the world - but my point was (and is), just be sure you're
comparing like with like, if possible.

Clive





> > From: Clive Smith <clive.harman-smith@NTLWORLD.COM>
> > Reply-To: Clive Smith <clive.harman-smith@NTLWORLD.COM>
> > Date: Wed, 21 Aug 2002 11:31:50 +0100
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: Oil Weight Reccomendation
> >
> >> But that doesn't explain why 10-30W is not good for it. Although the hp
> >> output of the mower may exceed that of my van....... :-)
> >
> > HP isn't the criterion, its the internal design of the bearing, engine
lube
> > pressure,
> > materials, clearances and nominal oil and peak component temperatures
(no
> > doubt amongst others)
> >
> > 10-30W could be far too low viscosity under cold conditions.
> > And the XX-YYW classification system doesn't inply that the viscosity is
> > higher at hot temps,
> > just that it lubrication properties 'simulate' that of a a YY straight
oil
> > at the upper temps and XX when cold.
> > Think of the origins of the classification system - a large body of
> > knowledge about straight oils and little if
> > any about multi-weight oils.
> >
> > Engineering can be a very grey matter (!), whereas arithmetic is
(usually)
> > quite black and white - but not always.
> >
> > Would we be able to compare a British Hi Fi at 25 Watts/channel with a
US
> > spec of something like 100 Watts,
> > just take most things with a pinch of salt, and always try and compare
like
> > with like (they're about the same!).
> > Another tip is to trust that design engineers know a little bit more
about
> > what they've designed than they are usually
> > given credit for, especially when it comes to Vanagons!
> >
> > Clive
> > '88 Syncro
> >
> > ----- Original Message -----
> > From: "John Brush" <jbrush@AROS.NET>
> > To: <vanagon@GERRY.VANAGON.COM>
> > Sent: Wednesday, August 21, 2002 6:15 AM
> > Subject: Re: Oil Weight Reccomendation
> >
> >
> >>>> I am ignorant of why straight weight even exists anymore. (and on a
lot
> >>>> of
> >>>> other topics as well)
> >>
> >>> 30 weight is what the manufacturers of my lawn mowers recommend.
> >>
> >> But that doesn't explain why 10-30W is not good for it. Although the hp
> >> output of the mower may exceed that of my van....... :-)
> >>
> >>
> >> John
> >>
> >
>