Bob Lang wrote:
>
> On Wed, 22 Jan 1997, Sholtes IV wrote:
> > Thank you for sharing your T.W. knowledge with us, but I gotta
> > know...HOW? How do you drive without using the clutch????
> If the car is rolling and you get the revs correct, you don't really need
> the clutch. I'm not saying that everybody should do this, it's just that
> after driving the car for 80000 miles or so, you get a feeling for which
> gear and revs combination applies for a given situation.
> I do this with all my manual transmission cars.
> I think this is why my freinds only rarely let me drive their cars! ;-)
Bob's right: Avoiding using the clutch isn't very hard to do.
Indeed, it is a good skill to learn for when you are miles from
home, and your clutch hydraulics fail.
I learned clutchless shifting right after I got my TR6, and was
able to make excellent use of it about 2 months later when my
clutch hydraulics failed, and I was 23 miles from home. (A TR6
is my daily driver for the entire summer each year, a clutch
failure is bound to happen eventually...)
I'll go ahead and take a stab at describing how I do it, and maybe
Bob can add his experiences, assuming he is doing the same thing:
How to shift without the clutch:
0) General
The steps described below must be performed *quickly*
and *smoothly.* It's really not as tricky as it sounds,
but does require swift, gentle motions to work, and
a fair bit of practice. What is described below is
really an extension of "double clutch downshifts",
except the clutch part is left out...
1) Upshifts (1->2, 2->3, 3->4)
When you get to your desired shift point, gently lift
off the throttle to the point that there is no strain
on the drivetrain (the engine is neither making the
car go faster, nor is exerting "engine braking") and
gently shift the car out of gear into neutral. This
will happen with surprisingly little pressure on the
shift lever when there is no strain on the drivetrain.
Continue lifting off the throttle, permitting the
revs to fall, while gently but firmly pressing the
gear lever into the next gear. (You need to press
firmly enough to exert some pressure, but not so
hard as to grind the gears.) When the revs have
fallen to exactly the same speed the gear lever
will practically drop right into gear, with no
grinding, and no clutch. To save wear on the
synchros, it helps if you press *only* at the
exact engine speed that the gear lever will
drop right in. This can be learned with practice.
(On a TR6, shifting out of gear at about 3600rpm
will put you into the next gear at 2200rpm for
each of the upshifts.) It also saves on the synchros
if you press as lightly as you can while still having
it work.
If you "miss" the shift point without getting
the car into gear, you're now essentially in
the Downshift case below...
2) Downshifts (4->3, 3->2, 2->1)
Downshifts are somewhat trickier than upshifts, but
are essentially the same as an upshift.
As with an upshift, when you get to the desired
shift point, gently lift off the throttle to the
point that there is no strain on the drivetrain
(the engine is neither making the car go faster,
nor is exerting "engine braking") and gently
shift the car out of gear into neutral.
Now, however, rather than continuing to let
revs fall off, as with the upshift, "blip"
the throttle, being sure to push the revs up
higher than they need to be to get into the
next gear, and then let the revs fall off
from that point. (You'll need to learn how
high you need to blip the revs, or just
blip up to the redline everytime... :-))
Now, as the revs fall off, gently but firmly
press the gear lever into gear, as was done
with the upshift. The only thing that is
trickier about this is that the engine is
now at high RPMs (3000-5000), and thus the
engine RPMs fall off much more quickly then
they would with the low RPMs (1800-2800)
typically encountered with upshifts. As with
the upshifts, you'll learn when to press the
gear lever into the next gear. Also, leaving
the throttle partially depressed will cause
the revs to fall off less quickly, and provide
more time to slip the gear lever into the next
gear.
If you "miss" the shift point, blip the
throttle and try again...
THAT'S ALL!
However, the above technique doesn't help when the car
is at a dead stop. Because of this, I think that even
Bob is using the clutch in this case. (At least I think he is,
unless I'm overlooking something.) I say this, because one
can't start from a dead stop without the clutch unless they're
using one of the following techniques (or, maybe, I'm missing
something.)
* Turn the engine off, put the car into gear,
and turn the key to start the car in gear.
This gives the car a fair jolt, but doesn't
grind gears at all. (Bob isn't doing this;
however, this is a good thing to know in case
you need to get home when your clutch has failed!)
* Lower the idle to ~300rpm, so that the synchros
can take the wear of sliding into gear. (I don't
know of any TRs that will idle that low.)
* Adjust the clutch so that it slips, allowing for
"easy" clutchless shifting (Bob's car isn't
setup this way, or he'd never be able to
climb mountain roads at the rate he does -- I
know, I had to keep up on the way to the '96
VTR National...)
However, excepting cases where one is starting from a full stop,
it is quite possible to drive without using the clutch at all.
The resulting effects upon your car depend upon how well you
do your clutchless shifting:
State of Excellence Results on Car
------------------- -------------------------------
Perfectly No wear on tranny synchros at all
Very Good Only normal wear on tranny synchros
Good Slightly accelerated synchro wear
Acceptable High synchro wear, occasional grinding
Poor Lots of grinding, torn diff mounts
Lousy Broken transmission after one day
Even a really good driver will have occasional problems with
clutchless shifting, particularly on downshifts. However,
one can definitely get to the point where the clutch is in for
an extremely short period of time, and is really only being
depressed to protect against a poor clutchless shift.
Anyway, enough of this dissertation. Since I've gone ahead
and written a small book, I'll take comments on the above
and then put the results on the VTR WWW pages for
posterity...
--ken
VTR WWW Maintainer -- http://www.vtr.org
'74 TR6 Daily Driver, for 6 months each year
--
Kenneth B. Streeter | EMAIL: streeter@sanders.com
Sanders, PTP2-A001 |
PO Box 868 | Voice: (603) 885-9604
Nashua, NH 03061 | Fax: (603) 885-0631
|