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Almost all good here except I have to correct you on Step 3. A few minutes isn't enough. I would give it at least a half hour before all the oil drains back into the crankcase. Otherwise you could get a false low reading.
Agree, but if you are simply checking for oil consumption, it shouldn't make any difference what interval you wait so long as you compare readings at the same time interval (although I would wait at least a five minutes).
 

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For manual transmission crosstrek, please make sure you never lug your engine especially when yo use low octane fuel. The detonation may damage your engine and cause high oil consumption. Never dump clutch aggressively from stop when you are on 0w20 oil.
 

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2018 Orange Subaru Crosstrek Limited
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Almost all good here except I have to correct you on Step 3. A few minutes isn't enough. I would give it at least a half hour before all the oil drains back into the crankcase. Otherwise you could get a false low reading.
It is hard to imagine, given how quickly the 0W-20 oil flows from the drain plug, that a few minutes isn't enough to get a close to accurate reading. It is better to give it more time than less as a rule though as long as you consistently test it the same way each time. I live on a hill, driveway slanted cross ways. I use "top-tier" gas, usually ARCO, and have made it practice to check my oil there, but I doubt they would like me hanging out for a half an hour to pull the dipstick. I just check the oil after a fill up, same way each time.
 

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For manual transmission crosstrek, please make sure you never lug your engine especially when yo use low octane fuel. The detonation may damage your engine and cause high oil consumption. Never dump clutch aggressively from stop when you are on 0w20 oil.
Lugging ANY engine is very hard on it even if you don't hear pinging. Think of it as the equivalent of the load on your knees while pedaling a bicycle from a stop while in too high a gear. If you cannot increase your speed while in a particular gear, you are in too high a gear for your speed, period. Revving is preferable to lugging.
 

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Lugging ANY engine is very hard on it even if you don't hear pinging. Think of it as the equivalent of the load on your knees while pedaling a bicycle from a stop while in too high a gear. If you cannot increase your speed while in a particular gear, you are in too high a gear for your speed, period. Revving is preferable to lugging.
Lugging bad if defined as putting a load on the engine that requires it to go below idle rpms or creating misfire/knock? Helpful to use Baseline Torque Map (generally, peak torque equates to best throttle opening/rpms for peak fuel consumption), but BMW found putting load on engine that doesn't create knock (rare now with computers for you to be able to do this) is extremely fuel efficient if boring way to drive. Crosstrek 145 ft-lbs of [email protected],000 rpm. Idle rpms are a good rule of thumb not to move below and are often on the edge of the blob of torque (BTM) available. I'm always assuming the Subaru is attempting to keep rpms as low as comfortable. Maybe I'll try manually shifting my auto as fast as possible keeping the rpms on the Subaru around 1500 but I doubt I'll beat the computer. My prediction, if I am able to do this, would be remarkably sluggish acceleration with a difficult to measure increase in mileage. I don't believe that this would cause harm to the car although I might get beat up by bicyclists trying to pass me.

Oh so very many years ago I helped build ARAMCO off road trucks with hulking supercharged 12 cyld engines (Detroit 12v-71: 1,200 lb⋅ft (1,627 N⋅m) @1,600 rpm) and you could take a tractor (no load) and drop the clutch on that thing at idle in any gear and motor off without touching throttle...serious, desert crawling torque and ratios.
 

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Lugging bad if defined as putting a load on the engine that requires it to go below idle rpms or creating misfire/knock? Helpful to use Baseline Torque Map (generally, peak torque equates to best throttle opening/rpms for peak fuel consumption), but BMW found putting load on engine that doesn't create knock (rare now with computers for you to be able to do this) is extremely fuel efficient if boring way to drive. Crosstrek 145 ft-lbs of [email protected],000 rpm. Idle rpms are a good rule of thumb not to move below and are often on the edge of the blob of torque (BTM) available. I'm always assuming the Subaru is attempting to keep rpms as low as comfortable. Maybe I'll try manually shifting my auto as fast as possible keeping the rpms on the Subaru around 1500 but I doubt I'll beat the computer. My prediction, if I am able to do this, would be remarkably sluggish acceleration with a difficult to measure increase in mileage. I don't believe that this would cause harm to the car although I might get beat up by bicyclists trying to pass me.

Oh so very many years ago I helped build ARAMCO off road trucks with hulking supercharged 12 cyld engines (Detroit 12v-71: 1,200 lb⋅ft (1,627 N⋅m) @1,600 rpm) and you could take a tractor (no load) and drop the clutch on that thing at idle in any gear and motor off without touching throttle...serious, desert crawling torque and ratios.
I don't know how you can set a baseline RPM for what is considered lugging. If you are going uphill, the point where you would be lugging is a much higher RPM than going flat or downhill. There is also a difference between whether you are increasing speed or steadily cruising. There are some situations where accelerating up some hills necessitates being at 3500 RPM's while cruising relatively flat roads is fine at only 2000 RPM's. Listen to your engine. If it's moaning, you are lugging.

Going below idle RPM, really? The engine would be shuddering horribly. You also do not have to be having engine knock to be doing your engine damage.

As I said before, if you are unable to increase your speed while accelerating, you are lugging.
 

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I don't know how you can set a baseline RPM for what is considered lugging. If you are going uphill, the point where you would be lugging is a much higher RPM than going flat or downhill. There is also a difference between whether you are increasing speed or steadily cruising. There are some situations where accelerating up some hills necessitates being at 3500 RPM's while cruising relatively flat roads is fine at only 2000 RPM's. Listen to your engine. If it's moaning, you are lugging.

Going below idle RPM, really? The engine would be shuddering horribly. You also do not have to be having engine knock to be doing your engine damage.

As I said before, if you are unable to increase your speed while accelerating, you are lugging.
After reading what I wrote I see that what you are saying is more intuitively correct. It's more complicated than my understanding understood. Your points about hills, loads and other variables.is correct as is your position on what might be correct rpms. Nice way to put it really: "...if you are unable to increase your speed you are lugging." Agreed.

In a poor way I was trying to say that BMW found (at mid-speeds on flat terrain) rpms that were quite low were quite efficient although not particularly appropriate for a person driving a nice performance car. I can't find the original articles that led to my misconceptions and Ill have to refresh. Yes, if you can't accelerate from your rpm gear combination then I would agree you are not treating your engine well.

I'd erase my whole post but it might serve as a bad example to inform others about how to get mixed up in the complexity of the thing.
 

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After reading what I wrote I see that what you are saying is more intuitively correct. It's more complicated than my understanding understood. Your points about hills, loads and other variables.is correct as is your position on what might be correct rpms. Nice way to put it really: "...if you are unable to increase your speed you are lugging." Agreed.

In a poor way I was trying to say that BMW found (at mid-speeds on flat terrain) rpms that were quite low were quite efficient although not particularly appropriate for a person driving a nice performance car. I can't find the original articles that led to my misconceptions and Ill have to refresh. Yes, if you can't accelerate from your rpm gear combination then I would agree you are not treating your engine well.

I'd erase my whole post but it might serve as a bad example to inform others about how to get mixed up in the complexity of the thing.
Your point is well taken regarding what BMW said. Awhile back I read somewhere that an internal combustion engine is most efficient at 80% load. However, I'm not sure that would translate to the best engine longevity. As far as where your best gas mileage would be achieved, I would say it's really a case of diminishing returns. Sure, if you are cruising at 3500-4000 RPM's, you will notice a decrease in mileage compared to a more reasonable cruising RPM in the 2000-2500 range. After all, if the inertia of your engine is drastically slowing your car down when you let off the gas while cruising, you are pretty obviously in too low a gear. I would also guess you would notice more difference in gas mileage at cruising speeds under 40. At highway speeds, most of your losses are due to wind resistance. I have noticed trips where the gas mileage was noticeably different depending on which way the winds were that day.
 

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Your point is well taken regarding what BMW said. Awhile back I read somewhere that an internal combustion engine is most efficient at 80% load. However, I'm not sure that would translate to the best engine longevity. As far as where your best gas mileage would be achieved, I would say it's really a case of diminishing returns. Sure, if you are cruising at 3500-4000 RPM's, you will notice a decrease in mileage compared to a more reasonable cruising RPM in the 2000-2500 range. After all, if the inertia of your engine is drastically slowing your car down when you let off the gas while cruising, you are pretty obviously in too low a gear. I would also guess you would notice more difference in gas mileage at cruising speeds under 40. At highway speeds, most of your losses are due to wind resistance. I have noticed trips where the gas mileage was noticeably different depending on which way the winds were that day.
Thanks! Trying to dig into where I got my ideas. Pretty sure it was a selective memory fart. What you say about wind and the BMW study is probably much more accurate and jibes with my experience on the long drive from Oakland to LA on our I-5. Wind changes mileage by about 1-2 mpg when present depending on strength. The question of when you are harming your engine is probably full of variables about load, wind etc. Driving a 750 hp piece of Detroit Iron probably could be done near idle speeds given the weight and CD of the car and not stress the engine but on the Crosstrek not so much. Fuel Mileage is complicated. Simple answers often fail to deal with that complexity. Mea Culpa. Think before you blog seems to apply to me on this.
 

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Thanks! Trying to dig into where I got my ideas. Pretty sure it was a selective memory fart. What you say about wind and the BMW study is probably much more accurate and jibes with my experience on the long drive from Oakland to LA on our I-5. Wind changes mileage by about 1-2 mpg when present depending on strength. The question of when you are harming your engine is probably full of variables about load, wind etc. Driving a 750 hp piece of Detroit Iron probably could be done near idle speeds given the weight and CD of the car and not stress the engine but on the Crosstrek not so much. Fuel Mileage is complicated. Simple answers often fail to deal with that complexity. Mea Culpa. Think before you blog seems to apply to me on this.
Point taken that the ideal RPM in any given situation would be less in a V8 than a 4 cylinder. Probably not near idle speed though, maybe twice idle speed while cruising on flat terrain.

From what I understand, larger engines not only don't need to rev as high, but it's worse for a larger engine to rev as high due to poorer heat dissipation than a smaller engine.
 

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2014 CVT with 160,000 miles. Never had to add oil between 7500 miles changes using the correct oil type. Traded it in today for a new 2020!
 

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I guess Subaru dealerships are considered "essential businesses"! 😸
 
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