Date: Mon, 18 Feb 2008 23:18:59 -0800
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: Electric Water Pump
In-Reply-To: <m13arp1mz9.fsf@cs.indiana.edu>
Content-Type: text/plain; charset="us-ascii"
Experiment of course, that's how gains are made.
But I would be very, very surprised if you can get any measurable increase
in fuel mileage in a vanagon by having an electric water pump instead of a
belt driven one.
The impeller portion is so small and easily driven, that I think probably
the drag of the v-belt driving it is a bigger factor than the load on the
impeller.
Additionally, in the whole scheme of what a vanagon is - a 4,000 lb box, and
given the crudeness of the waterboxer engine breathing ..............the
water pump is about .oooo2 % of a factor in fuel consumption.
Like I would be shocked if there was a measurable increase by going to an
electric water pump.
But someone should experiment.
Fuel economy is usually gotten by low aero drag, low rolling resistance,
small engine, and often low rpm or very high gearing, and a high running
temp. How efficient the engine is matters too of course.
But a vanagon .............you got a lot to overcome there for fuel
mileage gains.
One guy was claiming 26 mpg on gasoline, with a subaru 2.5 engine at
65ish........
Which I a little skeptical about. Anything in the low to middle 20's at a
decent cruise speed of 65ish for a gasoline vanagon is 'about it'
........unless someone can unleash something really significant, ( I do have
an idea in mind too, an aero improvement ) or numerous incremental
improvements.
I don't especially think a stock body gasoline vanagon with adequate
performance and power can do over about 24 mpg at 65ish mph, tops. Maybe
24.5 . One subaru 2.2 conversion I did, the guy reported 21 to 22 mph inn
really hot summer temps at high altitude, with one tank 24 mpg.
I'd like to see some gasoline vanagon with adequate power and performance do
better than that, in 'real operating ranges' of 50 to 70 mph, not an odd
steady 40mp or something not practical like that.
If you want a shock, calculate miles per dollar sometime.
My all time record is putting a hundred bucks in an envelope, and only
buying gas out of that, for a 56 VW Commercial Bus . doors on both sides.
In the 70's. Drove 3,200 miles on that hundred bucks for 32 miles per
dollar, on the open spaces of Nevada.
These days I'm 20 mpg at $ 3/gallon = 5 gallons to go 100 miles - 15
dollars to go 100 miles, equals ..........what is that, 6 and a half miles
per dollar or so. That sounds awful !
Anyway, I want to see someone do in the mid 20's on gasoline, in a vanagon,
at decent speeds, and with adequate power and performance, or even a solid
25 mpg. That would be quite an accomplishment to get up to that kind of mpg
*commonly* and like 'mostly most of the time.' .that would be phenomenal
even.
Scott
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Allan Streib
Sent: Monday, February 18, 2008 10:26 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Electric Water Pump
Kenneth Lewis <kdlewis@NORTHSTATE.NET> writes:
> I agree with your assumptions as they apply to FWD cars that
> require paltry amounts of coolant and only have to push it a short
> distance. But what about Vanagons which hold gallons and have round
> trips measured in yards? I would think that would greatly increase
> the load on the water pump. I have compared a new pump to an old
> one. The wear on the impeller blades is very evident . So an
> electric driven water pump might prove a healthy gain in FE (fuel
> economy).
A worn impeller is caused by corrosion and/or cavitation. Neglecting
to change the coolant as specified is often a contributing factor, or
it could be poor quality materials in the manufacturing process.
Allan
--
1991 Vanagon GL
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