Date: Fri, 17 Oct 2003 10:34:38 -0700
Reply-To: Pensioner <al_knoll@PACBELL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Pensioner <al_knoll@PACBELL.NET>
Subject: Re: The Ideal Vanagon
In-Reply-To: <200310170409.h9H49Bnw138652@vmj-ext.prodigy.net>
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Re: Your idea of the perfectengine upgrade (subaruvanagon)
Actually, Mark, I wasn't very clear that it was just my view of
requirements. But, let me re-state the query. What is the
group's "perfect engine upgrade"? We all have our own views on the
ideal.
From the numbers standpoint, on level ground at constant velocity the
thrust (torque) requirements for a vanagon are made up of the force
needed to counteract wind drag, bearing and machinery losses,
hysteresis in the tire rubber and some less significant factors.
You're certainly correct that for acceleration either a constant
velocity uphill, which would require proportionally more thrust
depending on vehicle mass/weight, or just speeding up on the level or
some combination of the two would also require proportionally more
thrust. I consider this thrust number to be a matter of personal
preference so to speak. I have ridden in a 7 passenger 2.2l
conversion and it was much better than the 2.1l WB. How much
is "much", I can't quantify that but I would prefer it over the 2.1l
based on my perception and my personal preference for better thrust
performance. I would also prefer the 2.5l PI to the 2.2 in the only
comparison that I have made.
I feel that if the 3.3 that I have was delivering to it's rated
potential that it would be on the order of twice the thrust of the
standard 2.1l. 185 vs 95 lbs-ft (approximation) The 3.3 is rated at .
180lbs-ft from 2000-5500 rpm with a peak of ~225 at ~4400 I can post
a new version of the "Smith Chart" that incorporates some analysis on
the thrust available given engine specification and gearing. I have
driven only one other SVX Vanagon, a non-westie, and the performance
seemed to be significantly better than mine. I have also driven a
2.5l PI, that seemed at the time to have more than enough thrust for
the particular application. I haven't had the opportunity to re-test
that particular conversion for comparison as it is "in the shop".
Regardless, my calibrated wallet feels only what is delivered by the
particular vanagon I drive. Warrrens 2.2l is certainly "peppy".
It's a westy, often bloated like mine with "expedition necessities"
to ~ 5000lbs and he is very statisfied versus the standard 2.1l but
wishes for the 2.5 performance. It would be nice to have better
numbers for a more accurate comparison but I don't.
As I infer but perhaps was a little vague about, the individual's
solution space on the set of measurable parameters is very personal.
For some, the value lies in a 22mpg 130 lbs ft solution. For others
they are willing to live with a lesser value for some particular
parameter set in order to gain in another set of parameters.
We would all like better "performance" in general, it's just the
definition of this performance function and the personal weighting of
the performance components that provides the selection criteria for
each of us.
So perhaps re-stating the question as follows, might provide
additional insight into necessaries versus desirables in pursuit of
the perfect engine upgrade:
"What are your five most valuable performance attributes ranked in
order of preference. Torque range, torque values, fuel economy,
installation costs, parts availability, fuel grade, fit, ease of
maintenance, suitable for hot climates ... are some attributes, you
may have others, all are worthy of consideration."