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Ok, given the same vehicle ( and about the
same weight ), how does one go about picking a replacement engine and
perhaps the replacing the transmission as well?
The reason I ask, is that I would like to
replace the engine I have with a better engine, but, I don't want to over
power.
Greg H.
----- Original Message -----
Sent: Tuesday, September 13, 2005
13:07
Subject: Re: [Biofuel] Debatable
statement?
I knew it wouldn't take long for these (good) questions to come up.
I'm just concerned that we don't get too hung up on cars designed for
maximum efficiency vs maximum power. Some of the methods used to get fuel
and air to high horsepower engines resemble toilet bowls and a lot of that
fuel ends up not getting burned.
The biggest question I have is; If you are including the vehicle as a
whole, weight has to be part of the discussion unless (perhaps) if you assume
regenerative breaking on all cars. It's tough to ignore the transformation of
energy into heat at the brakes.
Mike
Zeke Yewdall <[EMAIL PROTECTED]>
wrote:
Are
we comparing exactly the same weight/aerodynamics/rolling
resistance car
here, with just different powered engines? Or complete
different cars
like a metro, corolla, and a ferarri.
I think for otherwise identical
cars, a medium sized engine (but
smaller than what most cars come with
nowdays) will get better
mileage, because it can accellerate fast enough
to get out of the fuel
dumping acceleration, and into more fuel efficient
cruising faster.
But if it's to large, it's less efficient at cruising
speed because of
low part load efficiency. And if it's too small, it it
always trying
futiley to accellerate, instead of cruising. Also, due to
real fixed
ratio transmissions, a less powerful engine may spend more
time at a
higher RPM, where the fuel efficiency in grams/kWh is less,
whereas a
higher power engine could downshift sooner.
There is
also the human factor, that a more powerful car will entice
lead
footedness and speeding, and thus get worse gas mileage than
an
underpowered car that you just accept your
slowness....
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