A little more on double-clutching

[erict@cta.com (Eric Thorstenson)]

Just wanted to perhaps clarify one aspect of this discussion
on double-clutching, namely that DCing has nothing to do with
hitting the proper engine speed for the next gear. You do that
with heel-and-toe, which may or may not be accompanied
by DCing. DCing is used to set the input shaft of the trans to the
proper speed.

(Al, I would propose that your improved clutch life is not a
result of DCing, but rather of heel-and-toe. Now, improved
synchro life, that's a major benny of DCing.)

On upshifts, DCing isn't generally necessary because with
the clutch in, the input shaft tends to decelerate, which is what we 
want. On a downshift, however, we need to accelerate the input
shaft, hence the need to breifly couple it to the engine while in
neutral. Assuming your heel-and-toe is good, DCing serves to 
bring the input shaft of the transmission up to the proper speed 
for the lower gear.

The same effect is achieved by shifting w/out using the clutch,
i.e., input shaft remains coupled to the engine and (assuming you
hit the right engine speed) is at the proper speed for engagement
of the next gear.

Incidentally, when it's really cold out, the input shaft may 
decelerate too much. Under these circumstances, a DC on the
upshift helps considerably.

Eric T.     '86 5kS
erict@ra.cta.com