Highway driving-Why is it good?

[Dually]

I know stop and go driving is bad unless your breakin a new engine but what good/benefits does highway driving do for an engine?Some people on another post mentioned driving hard and working the engine but not abusing it.I would think that you want to get your engine nice and hot like a diesel and clean her out.Thanks Joe

 

[Quattro Pete]

There's nothing really "good" about hwy driving. Any kind of driving results in wear and tear. It's just that hwy driving is "less bad" than city driving because cruising puts less load on the engine than constant accelerating (like in stop and go).

Getting the engine "nice and hot" can be done in city driving as well. No need for hwy driving specifically.

 

[Gary Allan]

Well, taxi service surely doesn't destroy an engine ..even with frequent switching out of open loop/closed loop operation for fuel management. The point is getting into the steady state (full warm up) condition. Most people don't get there for very long. Longer highway commuters, just like taxi engines ..do..and for a larger chunk of their life cycle. Most engines exist in the accelerated wear zone, time wise, for all of their life. Obviously, even with this usage, they last.

 

[rpn453]

Yep, highway driving just gives you more miles per unit of engine wear than city driving.

 

[surfstar]

...not to mention less braking, shifting, starting, etc.

Much easier to stretch the MTBF for many car parts with highway miles.

 

[javacontour]

I agree with the notions of more miles travelled per unit of engine wear argument.

I also believe that SMOOTH driving is a critical component of long life.

One can drive on the highway, but if they don't anticipate what's going on ahead, then they will put more stress on the vehicle than someone who can drive smoothly. Keeping a safe distance from the folks in front of you so you don't have to make as many sudden stops and other things.

 

[surfstar]

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Keeping a safe distance from the folks in front of you so you don't have to make as many sudden stops and other things.

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If more people drove like this, crowded freeways would be much more pleasant and smoother (not to mention better overall MPG for everyone); but alas, everyones gotta sneak in front of you if you leave more than a car length gap.

 

[javacontour]

So, I just let them in. It's a lot less stressful than trying to keep the gap so small someone cannot get in.

Frankly, the difference in travel time on a 20 mile trip from 60 vs 80 MPH is not really worth the stress. At 60 MPH, the trip takes 20 minutes, at 80 it will take 15 minutes. If I cannot adjust my life to leave 5 minutes sooner, I have bigger problems than the guy cutting in front of me on the freeway.

 

[tom slick]

everything is relatively constant when freeway driving, air flow is constant to the radiator and through the intake/engine. the transmission is in a constant gear. RPM are constant. oil flow is constant. fuel flow is constant. compression/cyl pressure is constant. load is constant.

all of this is less stressful then the constant change while accelerating and decelerating in city traffic.

 

[BrianWC]

Highway miles means no constant acceleration and deceleration which stresses the timing chain/belt along with other engine internals. Also, fuel air is typically closer to stoich for longer periods, meaning less fuel-rich blow-by into the oil. Sure, a hot city-run engine can evap it off, but less is there to begin with if you aren't stopping and starting. Of course, short trips without proper warm up of the engine means the additive package has to cope with the contaminants without the benefit of a toasty engine to burn them off.

 

[AEHaas]

This one is easy. First let us just talk about the normal driver, not somebody who is driving as if he has a Ferrari. It is all a matter of how much time is spent in the 20 to 30 minute start up period in the life of the car. You first have to define highway mileage. For me it is driving with more time spent after the engine oil warm up time. In other words a one hour trip would consist of 30 minutes warming the oil up then driving for the next 30 minutes with the oil at full operating temperature. This for me is a 50 - 50, city - highway driving situation.

Ref:

Effect of Break-In and Operating Conditions on Piston Ring and Cylinder Bore Wear in SI (Spark-Ignition) Engines, Schneider et al:
The rate of wear is much higher within 15-20 minutes of start-up than after reaching normal operating temperature. There was a lot of data but I conclude that the initial start-up time period (first 20 minutes) result is 100 nanometers of wear whereas the steady state wear rate was only 4 nanometers per hour thereafter. (Hence we should be concerned about start-up oil thickness more than running thickness. This justifies the statement that 95 percent of engine wear occurs just after start-up).

Typically people who put a lot of miles on their cars over a 1 month period spend a lot of time on the road. It is much more time consuming to put a lot of miles on a car by doing 15 minute trips across town.

aehaas

 

[bdcardinal]

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Keeping a safe distance from the folks in front of you so you don't have to make as many sudden stops and other things.

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If more people drove like this, crowded freeways would be much more pleasant and smoother (not to mention better overall MPG for everyone); but alas, everyones gotta sneak in front of you if you leave more than a car length gap.

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we must live in the same city ;-).

o and if you ever see a loud black mustang slide in front of you, sorry. i can keep a shorter distance to people in front of me because my car stops better than 95% of the other cars on the road.

 

[brianl703]

I think it's just amazing when I95 goes from moving at 75MPH down to 50MPH and back up to 75MPH again all in the timespan of a minute.

Then you get the people riding your #@$%! at 70MPH in the right lane (speed limit is 65MPH) because another #@$%! is going 62MPH in the left lane.

I'd just as soon prefer to take US1 instead of that highway from #@$%!.

 

[Junior]

This is why people need to learn to drive to the right and get out of the way. If someone is behind you while in the left lane, speed up, make the pass and get out of the way. (provided it is not bumper to bumper in all lanes)

 

[ThirdeYe]

I see that way too often, with people clogging the left lane by doing 5 under, and REFUSE to get over, even if they have the room to do it, causing backups on the entire highway. Can't stand that.

 

[brianl703]

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(provided it is not bumper to bumper in all lanes)

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I95 has enough hills that you can see for up to 1/2 mile back in some places.

You know how many times I've seen bumper-to-bumper traffic 1/2 mile behind me, with three cars at the head of it, driving side-by-side in all three lanes?

There might be 4-5 cars in the 1/2 mile between that rolling traffic jam and me.

The only reason I'm not stuck in that mess is that I happened to merge onto I95 in front of it.

Frankly, I don't know why the people out in front aren't getting tickets. It's easy enough to see what's going on from I95 itself, it should be even easier to see it from the air and they already enforce speed limits from the air so...

I guess it's a matter of priorities.

 

[JHZR2]

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I also believe that SMOOTH driving is a critical component of long life.

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This is the #1 key.

WHile everything being up to temperature, oil add packs being fully active, etc. is important, the one thing that kills a vehicle the quickest is the driver.

Tools that dont understand physics cant possibly hurt their vehicles on the highway as bad as they do speeding off from every red light and slamming to a stop each time. Sure, they drive and brake and downshift too much, etc., but the number of occurrences, compared to their poor city driving habits are much lower, thus less wear per mile and thus more longevity. Remember, vehicle longevity is seldom governed by engine life (that is just a good metric because so much money goes into development, and most folks consider it the generic most important part ofthe vehicle, so it sells the most 'service' and thus is considered the most closely) - it is the $1500 worth of suspension, the $500 brake job, another $500 for tires, on top of a $2000 AT rebuild job, which all come more or less at once, that determine to most jerks that a car is shot. Little do they realize that their own stupidity caused all of that stuff to need to be done much faster than it would have otherwise, if at all...

If people werent such idiots, vehicles would last a LOT longer.

JMH

 

[bretfraz]

Agree with the sentiment that typical city/stop & go driving increases wear more than hwy driving reduces it.

Think of all the upshifts and downshifts you make in typical suburban or city driving.

Think of the turns the work the steering system, the rought roads, potholes, speed bumps that are wearing the shocks, struts, ball joints, control arms, springs, etc.

Think of the hundreds of times you use the brakes, many times while turning and driving on rough roads.

On the highway, little of the above is happening. Not only are the fluids up to temp but so are all the systems. The trans is in top gear and happy. The engine is running in its temp range and has little load on it. You are not turning so the steering components are doing almost nothing. The road surface is in good condition by comparison so suspension wear is minimal.

It's not the engine wear that's an issue, it's the wear on all the other subsystems. I've noticed this with service trucks and vans - the drivetrains are fine but the rest of the vehicle is literally falling apart after 150K or so. Brakes shot after 25K, tires don't make it past 30K, suspensions slap wore out before 100K. Even over 200K the engines and trannies work well, but everything else is junk. A few vehicles are loaded up and some tow but most are just used in everyday city and suburban driving on paved roads and see little actual highway miles.

 

[1sttruck]

You might need to compare engine hrs vs miles when comparing something like delivery vs highway, but severe service in my vehicle not only consists of towing but also lots of stop and go and idling. Lots of idling is probably harder on diesels than gass engines as the engines cool too much. It seems that cold starts produce the most wear, as well as cold temperaures. As I recall my former 68 VW bug needed 500 mile oil changes in arctic conditions.

 

[SargeGTO]

Steady Air Fuel mixture at highway speeds also is a key contributor to easier miles versus up and down on the RPM's.