If all this stuff seems wacky, let me just list
a few of the measures I know of that were
taken to improve fuel economy:
1. Reduce spring tension on lip type oil seals
2. Stronger brake pad hardware (to lessen pad
drag against the rotor)
3. Elimination of tapered roller bearings in favor
of ball or roller bearings; this reduces turning
torque requirements by eliminating the drag caused
by the preload of a tapered bearing.
4. Window glass thickness reduced.
5. Higher efficiency oil pumps and oil pressure
controls inside automatic transmissions
6. Reduction in cross sectional thickness of
piston rings (lower scraping friction)
At Toyota we also had:
7. Multipiece hollow crankshafts
8. Multipiece hollow camshafts
After going through all that, I think it's
safe to say that changing accessory
drive configurations wouldn't be done
unless there were significant improvements
in almost every area. Quality, NVH (noise,
vibration, harshness), fuel economy, vehicle
weight, acceleration, cost (yes, it has to be
affordable), and many other factors apply.
All I'm trying to say is there is a lot more
than meets the eye to most of the design
decisions made in vehicle design. Cost is
only one of them, and quality (at least where
I came from) ranked very high.
Jim McShane
Hi, Jim,
I respect your commitment to quality and technical improvement. Your 'get
it right' attitude is very thin on the ground here in the UK. Your last
paragraph is the whole crux of the thing. We can all speak from personal
experience or experience within the industry...
There are many different ways of looking at things....... you need to
examine them all..
Stronger brake pad hardware...
You view it as a fuel economy measure. An engineering solution. A step
forward. I see it as a move to further extend service intervals.. I'm down
here at Base Camp.
If your market sector competitor is on 10,000 mile service intervals,
pushing this out to 15000 or 20000 miles is a tool the
salesman can use in the showroom. 'Yessir, I know the Dodge is $500
cheaper but this Toyota costs $700 a year less to maintain..?? ... hey,
we're talking quality here !!!! You got the picture ?? Does the Dodge
really measure up ?? You look an intelligent guy to me...
Years ago contact points and plug life fixed the service intervals. Now, it
is how long modern lubricants and friction materials last.
Taper rollers ?? Rollers are better able to handle radial loads than ball
races. Roller bearings are worthless at handling axial loads. There is
substantial axial loading whilst cornering, so the taper roller is the ideal
solution. It's been around for 100 years... Toyota spotted something the
rest of us have missed ?
No.. A complete hub with ball races and a spacer between them can be
airwrenched up on the line by a monkey, or a robot. A taper roller requires
adjustment.. Once adjusted, it has nil preload, does a far better job, and
has no more frictional drag than ball races
A monkey can't adjust it properly though.... a robot could get it wrong
2.25% of the time.. Delete it !!!!! We go with the ball races ...
Thinner window glass ??? Find me a safety or strength reason why this is a
good idea compared to saving a few cents ??
Lubrication improvement in autotrans boxes ?? Hey, were now out at 20,000
mile service intervals. The transmission could fail before the brake
friction materials or the door glass.. Increase circulation by 10% and go
for a fully synthetic lubricant.
Go back to first paragraph. Jim, I respect you as a dedicated engineer. I
am. I have mechanical engineering certificates to prove it. I learnt how you
did it properly, then I walked into industry and met two people. One was an
accountant who said it cost too much. The other was a production engineer
who said it took too long.... Could I adjust my engineering to suit ??
Engineering is alive and well in the US and the UK.. It's at AC, Aston
Martin, Cosworth, Lotus, Penske, etc, etc...
Toyota, Ford, GM, Chrysler, Rover, Nissan just make cars..
regards
jim
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