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Sherlock Ohms

Balancing Efficiency and Comfort in a Ford

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cookiejar
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Gold
What comfort?
cookiejar   1/7/2015 7:47:12 PM
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For me there are two fundamental things that define comfort in a car.  The first is room enough to fit comfortably and the second is a smooth ride.

Being 6'4" as are my two sons, we find that fitting comfortably in the back seat is a major problem in most cars these days.  The current style demands that the roof slope downward towards the rear of the vehicle so one's head is hard against the headliner or worse, hard against the rear window.  Of course there wasn't the problem with any of the higher profit margin SUVs or trucks, until recently when even stylish SUVs and vans are getting the same downed roof treatment. 

At one time many cars rode smoothly.  The automotive press quickly put an end to the smooth ride by rating all vehicles by their performance on a race track, including Consumer Reports.  So now they all have hard low profile tires and firm suspensions.  I started developing a severe pain in my neck while driving, caused by my vehicle's jarring ride. As it turned out my vehicle's ride quality was rated as 4/5 by Consumers Report.  So I dug into CR's back issues and had to go back to 2007 to find a vehicle with 5/5 ride rating.  So now I drive a 2007 Buick Lucerne with magnetic ride and my pain in the neck is gone.  Road and Track magazine lament the passing of the smooth riding cruisers with the only smooth vehicle left being the Chev Suburban SUV with magnetic ride.  Road and Track haven't figured out that they and other automotive journalists are responsible.  Let's face it, 99.9% of drivers don't have a clue as to the handling limits of their cars, let alone be able to take advantage of them in an emergency.  I found skid control school to be an eye opener.  The Buick Lucerne CXS handles superbly.

There are now more vehicle models available than ever before.  You would think that at least a few would have adequate room for passengers and ride smoothly enough to not cause health problems.  Car manufacturers these days behave like a herd of sheep.

tekochip
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Platinum
Re: What about manual?
tekochip   12/21/2014 4:29:45 PM
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The little bike had about 70K on it at the time, the clutch was badly worn and I kept snapping off clutch cables from the excessive pull.  The clutch only slipped during cruise, in 5th gear, on level terrain, between 30-50MPH, so the sudden surge was quite noticeable.  The brave little 125 could hit 70MPH, though, and got about 90MPG.

It was a `72, orange, F6 that made its rounds through the neighborhood.  I swear everybody in town owned that bike at some point in time.  I had it about two years and after I sold it the original owner came around to buy it back.  I gave him the number of the new owner and he did get his bike back.

RFI-EMI-GUY
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Silver
Re: What about manual?
RFI-EMI-GUY   12/21/2014 3:23:45 PM
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Some motorcycle clutches are wet clutches. They are designed to be exposed to engine oil and should not slip unless there is excessive wear, weak springs or an adjustment problem. Two stroke engines can have very peaky torque curves, so most likely you were running under a condition where the throttle was at peak power and the load was increasing.

tekochip
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Platinum
Re: What about manual?
tekochip   12/21/2014 8:24:50 AM
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I knew slipping was a failure mode, I was just curious if it was considered normal to slip a little during cruise.  Sliding friction is always much less than static friction, so I thought it would be a bad idea to design in some intentional slipping.

I had a motorcycle that would slip from time to time.  It was a really old two-stroke, I think an F7, anyway I'd be driving along and there would be a sudden surge when the clutch slipped, "eeeeee WEEEE eeeeee".  The bike had a loose chain too, and one day the chain slipped off and wrapped around the axle, locking up the rear tire.  That's another story, though.

RFI-EMI-GUY
User Rank
Silver
Re: What about manual?
RFI-EMI-GUY   12/20/2014 10:58:42 PM
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tekochip;

I had a 1967 MG 1100 sports sedan (manual 4 speed) that I drove from Maryland to Chicago one year. Things running really well until halfway through Ohio I heard an "airplane buzzing me" louder than the radio. Checking again I found the revs were way up on the engine and the car was slowing down. I pulled over and found engine oil (interstingly the gearbox shares same oil/sump on this model) pouring out of the clutch housing and some awful smoke.

That ended my trip at that portion requiring Greyhound the rest of the way.

So yes a "manual transmission can slip during cruise" but is never a good thing to happen.

I learned from owning a British car that failure occurred always without prior notice.

OLD_CURMUDGEON
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Platinum
Re: What about manual?
OLD_CURMUDGEON   12/17/2014 10:43:34 AM
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I wouldn't recommend the frequent use of relaxing the accelerator & shifting up with a synchro-meshed manual tranny.  The synchro gears were (are) made of hard brass, which wears significantly quicker than the steel gears in the transmission.  Continued use of this "trick" will only shorten the life of those synchros.

I've owned many vehicles with standard shift transmissions in my long driving career.  And, I've had clutches slip, especially when extremely hot either due to ambient weather conditions or load.  IF the flywheel face OR the clutch disc gets "polished", they are more likely to slip, even under moderate loading, and gone a re the days when the clutch disc was an asbestos plate, which could take the elevated temperatures from the high frictional component of the drivetrain.

wbswenberg
User Rank
Platinum
Re: What about manual?
wbswenberg   12/16/2014 7:22:05 PM
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Yes, a manual transmission can slip.  I have a 1995 K2500 4X4 with about a ton of camper in the bed.  It has a 350 cid and manual 5 speed.  If I push it too hard the clutch heats up and vaper forms (i believe) in the hydraulic clutch.  Can't take it out of gear.  Hopefully I can pull over and kill the engine.  After it cools off a few minutes I get the clutch back.  I've had to start it in 1st grear and it will walk away.  With a fully syncronized transmission I do not have to push the clutch in every time just back off the throttle and I can shift it.  Needless to say I try to stay away from this condition.

tekochip
User Rank
Platinum
Re: What about manual?
tekochip   12/10/2014 2:58:25 PM
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I've never owned an automatic, so I was a little uncertain, and even with 250K miles on some cars, I've never worn out a clutch, so I was a little confused.

Yes, I push in the clutch (all the way) to prevent lugging and will also push in the clutch sometimes when going over bumps.  Here in the USA manual transmissions aren't that popular, but even the ultra high-end cars use them in Europe.

I had some German clients visiting once and they had never driven an automatic.  These guys were engineers, but simply backing out of a parking place was nearly impossible.  Speaking only a little English, they had no idea what PRNDL stood for or what the normal placement of the different gear positions would be.

 

Critic
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Platinum
Sales Pitch
Critic   12/10/2014 2:27:53 PM
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I was wondering how this qualified as a "Sherlock Ohms" article at first, but later realized that it is the software that helped solve a problem, and this amounts to a software sales pitch.

Critic
User Rank
Platinum
Re: What about manual?
Critic   12/10/2014 2:22:56 PM
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I should add that in the case of a manual transmission, the driver has control of the clutch slippage, so if he/she wants to accelerate, he/she could slip the clutch and downshift to prevent lugging.

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