Re: CVT vs Selespeed

[Scott Fisher <sfisher71@domain.elided>]

--- Keith Walker <100662.3423@domain.elided> wrote:

> Automatic cars can fiddle things a bit for the
> official fuel economy tests

As always -- and I would bet a nickel (big money for
me!) that the Multitronic (Audi's CVT) was tested in
whatever passes for "economy" mode.  Nizam's comment
about being able to select different gearing rates for
different circumstances sounds... interesting.

The other thing that I find interesting about
Multitronic is that the marketing makes much of it
having a number of preselected positions, simulating
fixed gears.  I'm not sure why -- I'd always thought
that an important point of any CVT was the ability to
optimize the engine's load for economy (or
performance), regardless of the road speed.  

> >>, lower overall drivetrain weight
> due to the lack of a torque converter,<<
> 
> Selespeed does not use a torque converter. It is a
> manual gearbox and clutch, but without a direct
> mechanical control for the driver to play with
> to operate these items. Far better than a slush
> box IF you like to play tunes with the gears.

Add Selespeed to the list of equipment I'd love to try
out -- have I recently whined that if it really was a
free market, I would own an Audi S3 (with stick) and
an Alfa 156 Sportwagon with Selespeed? :-)

> >> better
> acceleration by 0.1 sec to 60 mph, and currently in
> use in vehicles with 220 bhp/221 ft/lb of torque
> (the
> most powerful engine available in their FWD range;
> Multitronic is not yet available with quattro).<<
> 
> Again I presume you are comparing the CVT Audi
> with the Tiptronic Audi,

No -- those figures are for the CVT/Multitronic versus
the 6-speed manual.  Though there appears to be some
variation, or perhaps rounding error; one page on
Audi's site listed the CVT as having a 0.1 second
ADVANTAGE over the 6-speed manual to 60 mph (close to
100 kph) but didn't list the time, but the
specifications/data page listed the CVT and manual as
having the same 0-60 time -- 6.9 seconds for the
3-liter A4.  

Both are noticeably quicker than the Tip, but from
experience driving my wife's '93 Audi 100CSQ with
automatic (pre-Tiptronic), I'd guess that this is
because the gear ratios in the Tip are meant to
optimize driving from 60-100 mph, not 0-60.  The
four-speed automatic in that car has a gaping hole
right where second gear ought to be, between about 30
and about 50 mph, but it happily kicks down two
notches from a 70 mph cruise.  And I don't know where
the natural upshift point into fourth is, as I've
always lifted before the transmission changed up for
me, but it's somewhere on the high side of 100 mph. 
Definitely autostrada gearing.

> and the Tiptronic box is
> just a slush box complete with torque converter
> but with an easy form of override to select the
> gear you want.

That would be my assessment of it as well, as an
occasional passenger (though never a driver) of
Tiptronic-equipped Audis.  

> >>Given the 1300's love of high revs, that would
> have been a wonderful pairing; I would love to drive
> such a vehicle.<<
> 
> My experience with CVT boxes has mainly been in
> small cars. One was so slow we thought there was
> a serious mechanical problem (a Lancia Y10), the
> other just confirmed how dog slow small CVT
> boxed cars are (a Fiat Punto). Both revved hard,
> but went nowhere.

Same as the autobox rental cars I seem to get stuck
with -- the right pedal changes the pitch with
kickdown, but has no effect on forward motion.

> They are also the reason we
> landed up buy a Renault Clio with a clutchless
> manual transmission.

The same description applies to my 356 at the moment,
sad to say...  with the difference being that it isn't
meant to be that way.

> Although you may land up revving the engine, you
> loose all feeling of throttle response, and it would
> certainly make adjusting the throttle used while
> cornering an unpleasant idea.

That is, of course, EXACTLY why I want to drive a
CVT-equipped car for myself -- to see what it's like. 
I've spent so much of my performance-driving time
learning to find that balance, giving the car just
*enough* power in a corner without giving it too much.
 Since reading about the DAF-equipped Alfa many years
ago, I've wondered what it would be like to drive a
CVT-equipped car in a sporting manner, or in
competition.

The closest I've come so far is the Malibu Grand Prix
cars, which use 440cc snowmobile engines and CVT
gearboxes, and it's been ten years or so since the Bay
Area autoxers used to go out to Redwood City and play
with those.  Not all that different in feel from the
centrifugal clutch and single-speed gear in a racing
kart, at least in the midrange, but NOTHING like the
feeling of coming on the cam, er, port in a
high-performance two-stroke when you get to the 14,000
RPM power peak.  Whoosh!

I've always wanted to drive a car with a Wilson
preselector gearbox, too, but that's from a completely
different culture (if not era) than either Alfa OR
Audi. :-)

But thanks for the additional information on the
Selespeed, Keith.  Even though it does nothing, I'm
afraid, to make me any happier that I can't go out and
try it out for myself...

Best,

--Scott Fisher
  Tualatin, Oregon
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