Date: Tue, 19 Sep 95 12:36:18 PDT
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Dave Kautz <dkautz@hpsidms1.sid.hp.com>
Subject: More Numbers! A Performance Index
VW Bus Highway Performance Index
The idea for this index originated at the Wailaki campout, where Bradley
asserted that Martha's 2 liter Vanagon Westy was less responsive on the
highway than his '66 with a 1600. Al Hubbard pointed out that the Vanagon
had much "longer" gears and was capable of top speeds in excess of 80 mph.
This aroused my curiosity as to what "ought" to be true, and with help
from the ever-generous Joel Walker and his outstanding library, this
index was concocted.
The index is an arithmetic model of highway driving. It is the sum of:
Peak torque at the rear wheels in 4th gear <simulating cruising on flat
ground> plus peak horsepower at the rear wheels in third gear <simulating
climbing a hill>. This sum is divided by vehicle weight. As this yields
a number below one in all cases considered, each result is multiplied by
100 to give numbers that appear more tangible. There are no units associated
with the index, the values are useful for comparison purposes only.
Just so you don't all rush out to buy 1500cc microbuses based on the index,
I've also included the engine rpm at 60 mph to give you an idea of the upper
end of the performance envelope. I had entertained the thought of factoring
the top speed of the vehicle into the index but decided against it after
realizing that many listmembers don't give a second thought to cruising
down the road at 4000 rpm plus - which will allow any of the buses in the
index to, at least, approach the national speed limit. I think we can all
agree that it is a given <with the exception of the Vanagon Diesel> that
the newer a bus is, the more relaxed "gait" it will have at highway speeds.
Dave Kautz
Bus Type RPM @ 60 mph Performance Index
1200 Micro 3719 64.5
1500 Micro <gearing for 1 ton GCW> 3575 67.0
1500 Micro Westfalia <extra 130 kg> 3575 59.7
1600 Breadloaf 3484 62.7
1600 'loaf Westfalia <extra 140 kg> 3484 56.4
1700 'loaf 3484 70.9
1700 'loaf Westfalia <extra 140 kg> 3484 64.1
1800 'loaf 3416 72.9
1800 'loaf Westfalia <extra 160 kg> 3416 65.0
2000 'loaf 3181 72.2
2000 'loaf Westfalia <extra 160 kg> 3181 64.4
2000 Vanagon 3072 66.9
2000 Vanagon Westy <extra 175 kg> 3072 59.4
1.9 Vanagon Wasserboxer 3267 79.1
1.9 Vanagon Westy <extra 175 kg> 3267 70.3
1.6 Vanagon Diesel 3650 52.3
1.6 Vanagon Diesel Westy <extra 175 kg> 3650 46.7
2.1 Vanagon 3072 81.4
2.1 Vanagon Westy <extra 175 kg> 3072 72.3
'
