Hours vs. Miles?

This is something that I have thought about for quite some time.

How come a cars usage is logged in miles and not in hours like boats? If one sits in traffic there would be less miles but more hours put on the engine. Not an ideal manner in which to identify use.

 

Often thought the same thing. No makeadasense

 

I suppose you also want to account for clutch, gearbox, diff., wheel bearing, brake wear etc. at the same time. Granted on a boat you have some other wear points too like rudder controls etc. but not to the same extent as in a car. Sitting in traffic is probably pretty insignificant from an engine wear standpoint especially with modern fuel injected cars (versus less accurate fuel mixture of carb'ed cars).

 

I think race cars usually are measured in hours.

 

Then you would have "hour roll-backs" instead of odometer rollbacks.

Also, if it was in hours instead of miles, then cars that are driven on the highwway more often will have higher mileage with lesser time since you would be racking up the mileage iess time than city driving. For example, 60 miles per hour on the highway for 2 hours would give you 120 miles, but how many hours of city driving would it take you to run up 120 miles?

 

Why not TOTAL REVOLUTIONS on the engine? Measured in MegaTurns

or TOTAL REVOLUTIONS on the wheels? Measured in KiloTurns

or TOTAL REVOLUTIONS on the government? Measured in shots fired/revolution

 

I suspect the reason started off for simplicity and clarity to non-technical owners.

BMWs have used a combination hr/mileage system for about 20yrs. There is an indicator on the dash which counts down to a service based on useage patterns, mileage and time as opposed to simply mileage.

 

It would also cut down on pollution and gas comsumption. Cars would idle alot less. They'd cut their engines off at red lights.

 

I love it..lol
at every construction site you'll find machinery left on with no one in it during breaks or lunch. Because the equipment is charged in cost by how much its used in hours

 

Note: This second one is directly related to miles.

ON the first one: Does a revolution at 1000 RPMs and low throttle position equal a single revolution at redline and wide open throttle?

{You can measure airplanes in hours because the engine is producing 70%-ish of its rated HP all the time in the air.}

 

usually it's the opposite, as large companies like a few I've worked for charge their divisions rent based on the hours on the equipment, and when I was a PM I'd chew your ass for leaving the equipment running during breaks or lunch... now if it was a T and M job, and the inspectors were checking the meters....

Whats really fun is that the old Cat dozers (probably more, but I know them for sure) had your typical hour meter, but it didn't keep accurate time, and sped up and slowed down with the revolutions of the motor. Old Superintendant told me one time that he had a job where they paid based off the equipment hours. After the first week of running it at fairly low rpms, and getting shafted on his paycheck, he figured it out. Unless he was on break, he kept it wide open, and made much better money.....

 

cause hobbs was a brit, not an italian.

 

Some interesting thoughts. I think ideally both hours and miles should be used.

 

I've had a Hobbs meter on my 308/GT4 for years. It's mounted right next to the coils and picks up 12V off the B+ post on the coil. I suppose you could pick up the D post (wire to the distributor) maybe inductively, and count the pulses or build a little circuit with a D to A converter controlling the voltage to to the Hobbs meter - more pulses per second=higher voltage to Hobbs=faster count.

Whenever I change the oil filter I mark the Date, Mileage and Hobbs reading on the bottom of the filter with a magic marker.
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My thought on that is the usage TYPE........ Most hour meters on, lets say commercial equipment, mowers, tractors are at WOT as designed to be. Boats are similar, running at 3000+ rpms (and remember these are 5500-5700 max rpm machines) and the sheer load they are handling is far above any car.

 

Not sure about this but, aren't F1 also logged in hours?