> I will be starting a long, 3000 mile , trip on Friday in my Vanagon with
> a broken speedometer.  I have ordered a replacement " cluster" from a
> used auto parts recycler, we used to call them junkyards, but it may not
> be here on time.  I have been using the tachometer as a rough estimator
> for speed, about 3000 rpm I think equates to slow highway speed with
> about 3400 rpm keeping me up with legal traffic, and 3800 rpm moving me
> with the faster traffic.  Can anyone provide me with rpm vs mph data
> from their experience?  I really don't want to drive 3000 miles at at
> 3800+ rpm.  Sam

actually, 3800 is good. 4000 is ok, but over 4000 rpm and your fuel economy
starts dropping. at least, as experienced and tested (by dufus little trip
computer in my 86 and 88 buses).

but the bentley gives 18 mph per 1000 rpm for at-the-wheel speeds in 4th
gear (non-syncro, non-camper, with standard 185/70x14 tires). what i found
was that it was closer to 16.35mph/1000rpm. so you could work out a little
table like this:

TACHOMETER  Walker's   Bentley's
RPM                   SPEED      SPEED
(in 4th gear)         (in MPH)   (in MPH)
  2000*                    32.7         36.0
  2200                     36.0         39.6
  2400                     39.2         43.2
  2600                     42.5         46.8
  2800                     45.8         50.4
  3000                     49.1         54.0
  3200                     52.3         57.6
  3400                     55.6         61.2
  3600                     58.9         64.8
  3800                     62.1         68.4
  4000                     65.4         72.0
  4200                     68.7         75.6
  4400                     71.9         79.2
  4600                     75.2         82.8
  4800                     78.5         86.4
  5000**                 81.8         90.0

* i wouldn't recommend going below 2000 rpm in any gear.
** you'd better have Big Brass Ones to be going this speed! and damned good
tires, too!

my speed is calculated at the 16.35/1000 and bentley's at the 18/1000.

good luck! hope it helps. remember that for the 2.1 liter engines. the Max
Torque rpm is about 3400 rpm. so if you stay above that, you'll have less
trouble making it up the hills. :)

joel