I read over the weekend (it was just a random article that popped up in one of my iPhone newsreader apps) a study on highway miles vs city miles. Seems highway miles for some cars aren't actually "better" than city, in terms of drivetrain longevity.

Got me to thinking about the Fit...

I mostly drive highway, and around here that's 70+ MPH - otherwise you risk squish like grape. In the 5MT Fit, driving 75 MPH equals around 4K RPM. I can't imagine this is great for engine life. Rings, bearings, journals, etc. Even with high quality synthetic oil, that's nearer to redline than idle for the majority of its running life. I know Hondas are reliable, but still.

A sixth gear would be great, but the bottom line the Fit, especially the first gen car, is designed as a city car, not a highway cruiser. I wonder if slowing down to keep revs below 3K for cruising wouldn't help with engine and drivetrain life expectancy?

Anyone have some informed thoughts on this?

 

Theoretically,increased rpm means less longevity of an engine because the piston speed (up and down in the cylinder) is increased , but that is offset by todays lubricants and parts fabrication and materials. Its also offset because the number of times the piston goes up and down is dependent on how far the vehicle is driven and what gear its in. At 3000 rpm in fifth is outdone by 4000 in a lower gear. and generally around town the car is in a lower gear than on the highway. I'd be more concerned about the rpm in town contributing more to cylinder and bearing wear than those steady speeds on interstates. I think there are any number of studies that agree with that. Short trips are worse than long trips.

 

Good question. I commute 90mi/day at around 70mph too.

Another way to think about it is engine load over time. Even though it's spinning at 4k RPM, if you're just maintaining speed, then it's not really applying a lot of load to the engine right? ... as compared to 'city driving' where there's a lot of acceleration/deceleration.

Another way to think about it is this - two engine's operating for an hour a day. Which seems like it would wear out first... the engine that drones along at 4k RPM for an hour or one that's 'city driving' for an hour?

I don't really know, but.. something to think about

 

Good routine maintenance will offset any potential harm done. Hondas are famous for longevity, period, not longevity given caveat A,B, or C. At 89K mine is still running like a Swiss watch, my driving is 85/15 hwy to city.

 

I drive miles at a time at 5000 rpm it top gear and feel very comfortable and at ease doing so.... Hondas do very well at high revs second only the BMW or maybe as well or better.

 

I used to have an Integra GSR and would drive everywhere at 4K+ just to have my VTAKK at the ready. Also had a WRX that I would never let dip below 3K to keep turbo lag out of the equation. My mechanic never really cottoned to the idea of keeping the engine on the boil like that, even at cruising with little load on the engine.

I run full synthetic with regular changes and otherwise keep up with my maintenance. I was just wondering if maybe slowing down and actually driving the speed limit (65 for the majority of my drive) with the engine turning fewer revs wouldn't improve the life of the drivetrain.

Once I get the Alfa repainted and reassembled, I'll drive that a couple of days a week (ie those days when it's actually running) and keep some miles off the Fit. It's paid for and under full warranty for 30k more miles, until 100k miles. I just want it to last. Austin is tough on cars...

 

I’ve got 154,000 on my GD3 Sport and I’ve held the engine at 6,500-RPM for a full hour at a time crossing the Appalachian Mountains maintaining 80-MPH every other weekend…held in 4th gear. You do the math…Honda makes great engines!

Need to add that this is taking place at WOT!

 

In the same gear it's the same number of engine revolutions per mile no matter how fast you drive.

 

So if you're in fifth and driving at 2000 rpm do you think the wear is the same as at 5000 rom ? The piston may go up and down the same number per mile but the piston acceleration is different - and so is the wear.

 

Wasn't commenting on that, only on the previous statement that lower rpm means fewer revolutions.

That said, if you think about it do most cars die or get junked because of engine wear? How many lubricated engine parts ever need replacing?

I think that eventually it's just not worth fixing a car when an axle breaks or a transmission has issues or the alternator or water pump dies or something rusts through or a windshield breaks... or somebody crashes into you and the repair cost exceeds the car's book value.

Let's look at two scenarios:
1. You change the oil and filter every 4000 miles. And it costs $25 (a reasonable do-it-yourself cost for 4 qts syn oil and filter, or the price of having someone do it for you using regular oil).
2. Same as above but only every 8000 miles.

The cost for #1 is $1250 over 200,000 miles. #2 is half that (and with a bit less engine wear since you're starting the car fewer times after oil changes, not to mention maybe driving to/from an oil change place less often).

Given that it's unlikely that engine failure will be the cause of any car problems, is it economical to change the oil so often?

 

I've owned cars that cost me more than the 'book value' because I couldn't afford to buy another car and therefore it was cheaper to fix what I had. I've replaced rear-end, windscreens, water pumps, alternators, generators, pulleys, head gasket, rear seal, wheel bearings, timing belt, radiators, gas tank, distributor, oil pump, fuel pumps, all to keep cars alive because it was all I was able to do.

Never did junk a car because I didn't change the oil often enough. Once owned a F-150 that leaked more oil than was worth changing and stopped changing the oil filter as soon as I realized the futility of it all. I still ended up being able to sell it for $250. It had no book value.

Can I say an engine ever wore out??? Well if everything around them does then I guess they have too. One of my VW's could only take hills in 2nd gear - that's close to being worn out... I then went into the service and my mother 'sold' the thing, pissed me off.

 

I had an '88 Mazda B2200 pickup that I inherited from my uncle with close to 300k miles. The engine did in fact wear out. I sold it for $300 and the farmer who bought it dropped in another motor the very next day while it sat on my front lawn and drove it away.

 

My Father In Law has a 2002 Pontiac Aztek (not exactly a gem of a vehicle) with around 260K on it and no engine problems. The last time I pulled the dipstick on it it the oil looked pretty sludgy. These are mostly highway miles and he doesn't drive slow by any stretch. I know it's kind of an apples to oranges comparison but judging from what I've seen I think your whole car will go before the engine does.

 

Steady state loading is almost always better on engines and machines in general than cyclical loads.

I have a 2001 Dodge Dakota with 206,000 miles and I'd say at least 75% of them are highway miles at speeds of 60 to 80 mph. The engine, transmission, transfer case, and both differentials (4x4) are original factory and untouched.

Good maintenance will make your vehicle last far longer than unsubstantiated internet theories.

 

out of curiosity do you know what manufacturer made the aztec ?

 

It's a Pontiac that was made from 01-05. It's basically a minivan with four doors instead of sliding doors. When auto magazines make mention of the worst GM cars ever built it usually makes the list.

 

Do you have a link to what you saw, I, for one, would be interested in reading it? What issues does it point out?

Sixth gear has been discussed on the forum a number of times. Watch for it as standard on the Fit next year -lol

Honda's not worried about the longevity but will do it for the economy.
If you use and change the oil as recommended I doubt you'll wear out the engine.
Problem is the rest of the car starts failing.

K_C_

 

Honda knows how to build engines. I wouldn't spend one second wondering whether driving 80 mph at 4k rpm is bad for the engine or not. I change the oil when the monitor indicates 20% life remaining, and I don't lose sleep over it.

 

In the 1990s One of our vehicles was an 82 Accord with automatic transmission... Other than brakes that my ex went through about as she did liquor and money I only replaced the spark plugs a carburetor float and alternator belt.... It was slower than my Fit, slow handling, unwieldy, uncomfortable, boring and bullet proof...It had well over 100000 miles many driven at WOT when my son decided to get drunk and hit a telephone pole totaling the car and snapping the telephone pole... I guess the car was a safe one since he and his passenger were not strapped in but still suffered no broken bones.... Honda has been manufacturing a single overhead cam 250cc motor scooter engine since the 80s that will spin at 13000 RPM at WOT for days at a time as was proven in the late 90s by a 6th place finish against big sport and touring bikes in the Iron Butt Rally that circumnavigates the U.S. I have known guys that tuned early Honda 305cc motorcycles that would scream at WOT for 50 miles everyday with the exhaust pipes glowing from heat and stay together.... I have all the confidence in the world that a stock Fit engine will easily last over 250000 miles driven at 90 MPH if it is properly maintained.