Don't be silly. Have you ever seen the Bentley or the parts catalog?
There are dozens of transmission and gear combinations, which only
demonstrates there is NO one best set of gears. Different situations
mean different gears, and different trade-offs. The hunt for better
mileage is only one (somewhat dubious) goal. Lowering engine rpm at
highway speed is a perfectly reasonable thing.
--- In ev_update@..., "Downtown Computers" <dkorb@...> wrote:
I am no expert.
My first inclinations however would be not change the gear ratio. A
lower ratio may only contribute to a higher level of unburned fuel
out your back side. Many misconceptions exist on the subject of lower
rpm may deliver higher fuel mileage. I personally know of several
examples where this would not be true and infact had to increase rpm
on a ford six cylinder 300 cu/in to get the sweet spot out of that
engine. It was installed in a e100 ford van. I finally got the rpm in
the range that proved to be much more efficient and some times got as
high as 23 mpg from it and commonly saw 21.
VW'S development of the boxer engine did rely on high torque and low
rpm which did serve them well for decades, but the newer engines have
a tendency to rev higher and smaller wheels help in this design with
the sole purpose of higher fuel economy.
I recently took a trip from the Canadian border to Kansas City on hy
I29 which has a posted speed limit of 75 mph along 2 states. While I
may be an exception....I posted my best fuel mileage while traveling
80mph in South Dakota and north Dakota which was 23.6 mpg. At slower
speeds my mileage dropped slightly to 22.7 and as low as 21.7.(read
wind events as well)
If you wish to try your theory on the cheap........mount some BIG
OLE TRAILER TIRES on the back of your van and watch your mileage
plummet. Your van will give you optimum mileage as the revs increase
even more than 4500 rpm.
My 93 EV w/automatic has 163 I miles on it and used less than 1/2
cup of oil at highway speed in 3000 miles and I pressed it into
service as much as the law would allow plus 5. It breaths very easy at
higher RPM and if you lug that engine, you are simply pouring raw
partially unburned fuel out the back. The gear ratio on your van
should not be tampered with.
----- Original Message -----
From: rabbit16v_77
To: ev_update@...
Sent: Sunday, June 01, 2008 9:13 PM
Subject: [ev_update] Transmission Gearing
I have a 1993 EV with a 5 speed manual trans and even though the
transmission is in good working condition it is a rather close ratio
trans meaning it revs high on the freeway. So, I have a few
questions for you gurus out there:
1. What type of transmission does the EV use? O2A?
2. What is the gearing for our EV manuals?
3. With a little swapping of parts, would it help my fuel
consumption if I were to put in a taller transmission? I have a
trans out of a 91 Passat that is just laying around and I know the
gears are good as I drove the car before I parted it.
I have to replace the rods and main bearings and since some
engineering genius decided to hid two oil pan bolts behind the
flywheel I have to pull the trans now. Sooo, I figured I may as well
replace the clutch and look into swapping the transmissions if it's
possible.
Thanks!
Dave
[Non-text portions of this message have been removed]
