Cruising regularly at 4000 rpm

[ermax]

Originally Posted by Tcoat

Almost everything you said here is a gross distortion of my points and as you said before this is like arguing religion. One side has facts and science to back it and the other has legends and faith. Each of us believe we have the facts and are not going to change the other ones mind.

In closing I will simply state that there is no significant difference between cruising at 2,000 and 4,000 and you are no "better" off. This is all I have said all along.

Tcoat riding a bike:
[ame="https://www.youtube.com/watch?v=T4Qw-bmt7Ss"]Low Gear Bike Race - YouTube[/ame]

Don't lie Tcoat, you know this is funny. Hahaha

[Capt Spaulding]

Originally Posted by Tcoat

You did make it multiple choice and I did give a very clear answer within those choices.
If any at all it would be too small too see.



I will rephrase my response and ask a question in turn

The heat is caused by friction.
What is the difference in the operating temperature between
2,000 and 4,000 rpms in these cars?

I may be mistaken, but people seem to be conflating the "speed" at which an engine turns with the overall "number of revolutions" it makes. Hmfrz' hypothetical does not get at the "speed" question but is instead focused on the "distance." Having both cars travel the same distance at the same road speed while on turns at 2000 rpm and other at 4000 rpm requires the higher revving engine to turn twice as many revolutions to go the same distance.

If you change the question and ask which engine would have more wear, one that covered 10,000 miles at 3500 rpm v one that covered 5,000 miles at 3500 rpm the answer is, I think obvious. Better for Humfrz to ask whether two cars cover the same distance with one at twice the velocity of the other (but still within the "normal" operating envelope of the engine) would experience differential engine wear is more like it.

Another question I have is what part of the engine are we talking about. Is it the bearings (rod and main), seals, cylinders, pistons, rings, water pump oil pump or what? As most who have spent much time in engines know, cylinders have a habit of wearing an a "hourglass" shape. The tops as bottoms exhibit more wear than the centers. Why? Because the lubrication film between the rings/pistons and the cylinders breaks down as the pistons slow to a stop at the tops and bottoms of their strokes. The centers of the bores, where piston speeds are at their highest, have the most effective lubrication because the oil film is more effective at the higher piston speeds.

Thus, it would seem that increased speed can result in reduced wear.

My conclusion is this is much ado about absolutely nothing. If you drive your car in a lower gear, your engine will turn more revolutions. Those extra revolutions will cause incrementally more wear. If you drive the same distance, in the same gear, but simply at a higher speed, (say cruising at 90 - 4000 instead of 80- 3500) the wear difference will be less than trivial.

[ImAdopted]

Originally Posted by Jordanwolf

No... it's infected even this part of the internet.... no......... not like this.... Next it's going to be "Unganda knuckles" on this forum... please no... the memes are too stronk.

[ermax]

Originally Posted by Capt Spaulding

I may be mistaken, but people seem to be conflating the "speed" at which an engine turns with the overall "number of revolutions" it makes. Hmfrz' hypothetical does not get at the "speed" question but is instead focused on the "distance." Having both cars travel the same distance at the same road speed while on turns at 2000 rpm and other at 4000 rpm requires the higher revving engine to turn twice as many revolutions to go the same distance.

If you change the question and ask which engine would have more wear, one that covered 10,000 miles at 3500 rpm v one that covered 5,000 miles at 3500 rpm the answer is, I think obvious. Better for Humfrz to ask whether two cars cover the same distance with one at twice the velocity of the other (but still within the "normal" operating envelope of the engine) would experience differential engine wear is more like it.

Another question I have is what part of the engine are we talking about. Is it the bearings (rod and main), seals, cylinders, pistons, rings, water pump oil pump or what? As most who have spent much time in engines know, cylinders have a habit of wearing an a "hourglass" shape. The tops as bottoms exhibit more wear than the centers. Why? Because the lubrication film between the rings/pistons and the cylinders breaks down as the pistons slow to a stop at the tops and bottoms of their strokes. The centers of the bores, where piston speeds are at their highest, have the most effective lubrication because the oil film is more effective at the higher piston speeds.

Thus, it would seem that increased speed can result in reduced wear.

My conclusion is this is much ado about absolutely nothing. If you drive your car in a lower gear, your engine will turn more revolutions. Those extra revolutions will cause incrementally more wear. If you drive the same distance, in the same gear, but simply at a higher speed, (say cruising at 90 - 4000 instead of 80- 3500) the wear difference will be less than trivial.

I agree with you about the distance variable in his test. Here would be my test.

Two engines on an engine dyno with proper cooling to simulate travel at 60mph. Both will operate 24/7 for one month. One engine will be turning 4000rpm the entire time and the other will be turning 2000rpm the entire time. No transmission, no distance is covered. I think it's obvious which one would wear the most.

And then a real world comparison. When cruising on the highway at a consistent speed, the same speed for an hour. Which one will have more wear, one that is driven the whole time in say 4th (yes one guy said he actually cruises on the highway in 4th) or one driven in 6th? Again, completely obvious. How much additional wear may be negligible I agree. But that doesn't change the facts.

As for which part of the engine would wear. Well any part that is moving. But primarily the ring to sleeve contact. If two parts are incontact with one another there will be wear. If the number of passes is higher in one scenarios vs another it will definitely wear more. Why are we even debating this (not directed at you, you obviously understand the topic)? It's so incredibly obvious.

[ImAdopted]

i do about 99% highway driving throughout the week and since im in no rush ever i cruise (my own opinion about cruise) around 102 km/h which puts me at around the 2100 rpm mark. reading this thread makes me worried now, am i gonna die? is my engine gonna blow?

[ermax]

Originally Posted by ImAdopted

i do about 99% highway driving throughout the week and since im in no rush ever i cruise (my own opinion about cruise) around 102 km/h which puts me at around the 2100 rpm mark. reading this thread makes me worried now, am i gonna die? is my engine gonna blow?

Yep. Too low. Hahaha. You need to put it in 4th. Get those revs up around 4500 if possible.

[ImAdopted]

Originally Posted by ermax

Yep. Too low. Hahaha. You need to put it in 4th. Get those revs up around 4500 if possible.

but..but its automatic and its not a dummy so i trust what it does ahhh. i'll just get rid of it so no matter what rpms you are at wear will happen lol

[Cole]

Originally Posted by ermax

I agree with you about the distance variable in his test. Here would be my test.

Two engines on an engine dyno with proper cooling to simulate travel at 60mph. Both will operate 24/7 for one month. One engine will be turning 4000rpm the entire time and the other will be turning 2000rpm the entire time. No transmission, no distance is covered. I think it's obvious which one would wear the most.

And then a real world comparison. When cruising on the highway at a consistent speed, the same speed for an hour. Which one will have more wear, one that is driven the whole time in say 4th (yes one guy said he actually cruises on the highway in 4th) or one driven in 6th? Again, completely obvious. How much additional wear may be negligible I agree. But that doesn't change the facts.

As for which part of the engine would wear. Well any part that is moving. But primarily the ring to sleeve contact. If two parts are incontact with one another there will be wear. If the number of passes is higher in one scenarios vs another it will definitely wear more. Why are we even debating this (not directed at you, you obviously understand the topic)? It's so incredibly obvious.

Kinda wanted to bring this up, but I was having too much fun reading the argument. It's common sense, in my opinion of course (and no, I'm not an engineery type science man, so my opinion is of course invalid). But, as you said, two cars, same distance, but one of them has an engine spinning at twice the speed of the other, how would that not inherently have more wear, regardless of how insignificant it is?

I understand that provided it's within operating spec, it will be fine, but theoretically, wouldn't it show twice the wear of the other engine?

[StraightOuttaCanadaEh]

Study results:

Inconclusive.

lol

[Jordanwolf]

Originally Posted by Cole

Kinda wanted to bring this up, but I was having too much fun reading the argument. It's common sense, in my opinion of course (and no, I'm not an engineery type science man, so my opinion is of course invalid). But, as you said, two cars, same distance, but one of them has an engine spinning at twice the speed of the other, how would that not inherently have more wear, regardless of how insignificant it is?

I understand that provided it's within operating spec, it will be fine, but theoretically, wouldn't it show twice the wear of the other engine?

I'd be careful about saying twice the amount of wear, someone might take that as:

base wear when car is running = 1

wear at 2000 rpm = 1.2

wear at 4000 rpm = 2.4

As opposed to, wear at 4000 rpm = 1.4

Disclaimer: Numbers are used as an example and no valid math was used here.

[Cole]

Originally Posted by Jordanwolf

I'd be careful about saying twice the amount of wear, someone might take that as:

base wear when car is running = 1

wear at 2000 rpm = 1.2

wear at 4000 rpm = 2.4

As opposed to, wear at 4000 rpm = 1.4

Disclaimer: Numbers are used as an example and no valid math was used here.

Or like the difference between "more" and "extra"

[Tcoat]

Originally Posted by Cole

Or like the difference between "more" and "extra"

The diference between your engine lasting 1,000,000 miles and 999,999.00000000000000000000000000009

[Lantanafrs2]

5000rpm and 15k oil changes. Rev er up!

[ermax]

Originally Posted by Cole

Kinda wanted to bring this up, but I was having too much fun reading the argument. It's common sense, in my opinion of course (and no, I'm not an engineery type science man, so my opinion is of course invalid). But, as you said, two cars, same distance, but one of them has an engine spinning at twice the speed of the other, how would that not inherently have more wear, regardless of how insignificant it is?



I understand that provided it's within operating spec, it will be fine, but theoretically, wouldn't it show twice the wear of the other engine?

Yeah for sure not double due to improved oil flow. But yes more, extra, additional. Hahaha