In a message dated 9/20/01 8:23:44 AM Central Daylight Time,
jemery@execpc.com writes:
<< Unless the LD's are radically different than any other diesel, all the
curves I have seen of fuel consumption v.s. speed show max efficiency (i.e.
lowest fuel consumption) occuring at the peak torque point which is
typically about half of the engines max rpm. It would be nice to see actual
test data for these engines however. >>
If someone has a copy of TM 9-2815-210-34 that is older than June 78, it MAY
have the horsepower/torque graphs. Many of the older (50's) engine manuals
have this info, I just don't know if they quit including it before the LS
were developed.
The fuel consumption of a LDT-465-1C at rated power is 64 lbs per hour, an
LDS-465-2 is 90 lbs per hour, almost a 50% increase (which corresponds with
its almost 50% greater horsepower, 200 vs 130). For the record, to burn
these amounts of fuel the LDT consumes 405 cubic feet of air per minute, and
the LDS-465-2 550 cfm.
On flat level ground, it is my impression that you do not run out of power,
but rather you run out of RPM. And the idea of trying to get 70 mph out of
it is about like trying to run a stock Corvette in the Indy 500....you may do
it for a little while, but neither is what the vehicle was built for, and it
won't last.
It is my humble opinion that the engineers at Reo motors in 1949 knew a lot
more about automotive design then me, or likely anyone on the list. If you
compare the M35 to other vehicles of its time, you see it was in fact quiet
advanced. When, 9 years later work was begun on the multifuel engine equipped
trucks, the objective was not speed, and there was a lot of engineering and
testing put into that effort. This family of trucks was not designed to be
driven primarily on dry, hard surfaced high speed roads. Floating somewhere
around the house I have a document that tells exactly what percentage of time
they were expected to be on highway, and its fairly small. Later vehicles
(FMTV, for example) were designed with the expectation that a large part of
their life would be spent on road.
My recommendation would be prepare the truck such that all the components are
functioning as the designers intended, and leave it at that. Your top speed
will likely be in the 55 to 60 mph range.
My .02,
David Doyle
This archive was generated by hypermail 2b29 : Mon Oct 08 2001 - 10:59:00 PDT