Holy Whacko (religious thread), Barney (Fred and Wilma thread)
Today couldn't one just find a junkyard Caddi CPU, sensors and
gauge, get your computer guy hacker to strip out non relevant
circuitry and remount it on a small PCB for less than $50 in
Today's money (inflation thread)?
Option 2 - buy a used aircraft fuel flow meter, give your
passenger (now copilot) a calculator (or abacus) and have him call
out the calculated MPG's. With top down, headsets would be
permitted. Add check lists, aux fuel pumps, 6 point harnesses and
cool Top Gun helmets. Now we're cooking (er....flying).
Mike L.
60A,67E,59Bug
----- Original Message -----
From: Barney Gaylord <barneymg@ntsource.com>
To: <mgs@autox.team.net>
Sent: November 14, 2000 6:58 AM
Subject: Fuel economy gauge - part 3
> In operation this MPG meter has almost instantaneous reaction
(bouncy MGA
> fuel gauge thread) to changes in throttle modulation, as fast as
the fuel
> flow will change at the entrance to the carburetor (leaky float
valve
> thread). The instrument reading during accelleration goes very
low, and
> during decelleration goes very high, much like the vacuum
operated
> "power/economy" gauge (current thread sidebar). As such it is
very
> interresting to watch while you modulate the throttle (how far
into the
> "power" range thread), and anyone can achieve 59 MPG for a short
moment
> simply by lifting the foot fully off the throttle at speed
(impress the
> passenger thread), but that yields very little useful
information about
> fuel economy, because those conditions are short term and
transient (like
> some folks interest in this thread). The only practical use for
this type
> of indication is simply to discourage you from tromping so hard
on the
> throttle ("loud pedal" thread), which is why the power/economy
gauges do
> not have numbered calibrations on the face (late model MGB
temperature
> gauge thread), and why they are so easily supplanted by an idiot
light
> theory of stupid drivers thread). In fact the idiot light may
be better
> suited to that cause (some useful idiot lights thread) because
it can also
> be keyed to engine speed as well as vacuum level (distributor
spark advance
> thread), and so actually encourage you to use higher throttle
settings at
> slower engine speeds (tough on the bottom end thread) to keep
the engine
> torque closer to the power curve where the thermal efficiency is
best
> (power curve thread).
>
> The real practical use of this MPG instrument comes at constant
cruising
> speed on the highway (does anybody really do that thread). Here
you get a
> readout of your exact fuel economy in realtime (appropriate
computer terms
> thread). As long as you continue at a constant speed in fixed
conditions
> (depends on the police population thread) the instantaneous MPG
indication
> is the same as the long distance average MPG result (useful
information
> thread again, finally). Perhaps the most important information
gleaned
> here can be the optimum cruising speed for best fuel economy (is
this the
> real world thread). As different camshafts yeild optimum torque
at
> different engine speeds (power purchase thread), various cars
are also
> geared to yield optimum fuel economy (remove two pistons thread)
at
> different ground speeds. When the national 55 MPH speed limit
was imposed
> (the not so good old days thread) it was widely advertised that
Chrysler
> corporation immediately started bulding their "49 MPH cars"
(misleading
> advertising thread), meaning that they were geared and tuned to
optimize
> the government mandated Corporate Average Fuel Economy
(government
> interference thread) in a lower average speed range than was
previously
> practiced (changing times thread). Unfortunately (depending on
your point
> of view thread) my 1975 Mustang-II was built to earlier
practices (good old
> days thread), so it turned out to get the best fuel economy at a
constant
> 62 MPH (try explaining that one in traffic court thread), which
is exactly
> what I wanted to know.
>
> The next thing you can learn from instantaneous MPG readings is
what
> happens to fuel consumption (sometimes more is better thread)
when you hit
> an upgrade and press the throttle a little more to maintain
speed going up
> hill (not letting the SUV pass you thread). With just a little
practice
> and a short learning curve you might watch ahead more (defensive
driving
> thread) and accellerate slightly before getting to the upgrade,
so that you
> can negotiate the hill at a reasonable but decreasing speed
(depending on
> who's in the rear view mirror thread) without pressing so hard
on the
> throttle. This is contrary to what a cruise control unit (lazy
driver
> thread) will do with the throttle modulation, but can in fact
achieve
> better fuel economy (prove it to me thread). Another bit of
useful
> information is what happens when you drive in a strong headwind
(I didn't
> know we were in Kansas thread) or tailwind (why did the chicken
fall down
> thread), and the optimum speed for best fuel economy changes,
possibly
> being a large change in either direction (back in traffic court
again thread).
>
> But IMHO the coup de grace on this list (foreign language
thread, but only
> if you don't speak French) would be to tabulate the real
(without prejudice
> thread) MPG effect at various speeds with and without overdrive
engaged (OD
> thread is obvious), and with a few different final drive ratios
installed
> in your MG (most desireable mod's and models of MG thread).
Similarly one
> could take the initiative to map differences in MPG related to
various high
> performance engine components, free flow exhaust, etc (more
power = less
> throttle = better economy thread), and maybe even investigate
the theory of
> incremental and cumulative fuel economy improvements through the
use of
> economy improving gadgets (snake oil ads thread) to the point of
less than
> zero fuel consumption and having to drain the fual tank
occasionally
> (useless jokes, endless run-on sentences, and overconsumption of
bandwidth
> threads). One might even aspire to the grand objective of
finally
> discerning the optimum cost-vs-benefit combination of components
for
> lifetime minumal operational cost of your MGB (this is the mgs
list isn't
> it?). One might also retire and grow old gracefully (old farts
thread)
> while attempting to achieve some minimal economic benefit
(offset by other
> important social benefits thread) for a dubious number of
disinterrested
> owners of useless old junk cars (flame suit thread). Then
again, one might
> also benefit by getting some sleep (dangerous drivers thread)
rather than
> sitting up all night corresponding on a mailing list (internet
addiction
> thread).
>
> Zzzzzzzzzzzz.......,
>
> Barney Gaylord
> 1958 MGA with an attitude
> http://www.ntsource.com/~barneymg
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