Downshifting to brake

[Marriott@grolen.com]

Greetings other members of this exclusive (read "big $$$$$$$) club,

Several things to note about comp. braking and downshifting:

1. Every time you use a mechanism, you're wearing it. When you shift
(whether up or down) you use:  the shift lever and all the linkages; the
hydraulics (MC and slave) or cable; the clutch pedal; the clutch boost spring;
the ToB arm; the Tob; the pressure-plate fingers, hinges, and springs; the
clutch disk, flywheel, and PP; the clutch disk springs. For braking:
pedal/return spring/MC/light switch/CC cutout, caliper, pads, rotor. I can
change my front brakes (rotors and pads) for $135 in 20 minutes. A clutch for
my 4kq is ??? and takes a few days, as I understand. On a related note, I ride
with some people who will hold the clutch in, while braking to a stop, and
downshift through every gear. Huh?

2. Going down I-40 from Flagstaff to the Colorado River while towing a
trailer is one thing, getting off a limited-access highway is another. Pushing
the brake pedal once, and loading all the suspension components once, causes
more wear to the drivetrain than three or four downshifts? How about the fuel
to rev the engine for each shift?

3. Shifting without using the clutch _will_ wear the synchros and/or
blocker rings, as applicable. Some people will say, "I've been doing
that for years with no ill effects." Well, the transmission isn't
designed to come out of gear while it's loaded _at all_. If engine or output
RPM change after you've gotten past the S/BR, but before you've engaged, you
will grind the gear. Everyone's BTDT. Gears are hard, and won't really wear
without abrasive, but they _will_ chip. The clutch is on there for a reason.

4. As far as "being in the right gear to get out of the way," I don't do
that either. It's five miles from my house to the highway, at 35 mph. I
don't drive in second gear in case a runaway truck is chasing me. Nor to
I go 60 in third, or 75 in fourth, on the highway.

5. I have more control over the friction brakes than the engine brake,
as my Girlings work the same every time. With three open diffs, who
knows what's going to happen. BTW, A4 folks, does the EDL work whilefor comp
braking? Interesting concept . . .

6. Heel-toeing and downshifting on the track is an invalid comparison to
street driving. It's by definition more aggressive. Just because my car
has great suspension and brakes and acceleration (yeah, right! ;-)
doesn't mean I flog it continuously. There is a time and place for
everything; just because I know how, doesn't mean I have to do it every
time.

7. My clutch pedal is never depressed for more than about one second at a
time.

8. I do match RPM while performing a non-double-clutch downshift.

Just my 0.03 Dm of mechanical design experience (at current exch, of
course :-)

James
James Marriott, BSME (603)483-8587 Auburn, NH
'64 Falcon Sprint Convertible, B&B 260 V-8 and CR 4-spd.
    GOES great. Stopping?!? 217k
'86 4000S wife's commuter (heated seats), 32 mpg, 100k ++ ?
'87 4000CSQ H-stock und daily driver, Hakkas & :-) , 140k