Date: Wed, 15 Dec 1999 19:17:37 -0700
Reply-To: Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Subject: Re: RPM vs MPH
Content-Type: text/plain; charset="iso-8859-1"
By stopwatch and without speedo last year, we were at exactly 72 mph
cruising at 4K. 27x8.50 14.
Karl Wolz
----- Original Message -----
From: Joel Walker <jwalker@URONRAMP.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, December 15, 1999 5:31 PM
Subject: Re: RPM vs MPH
> > 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
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