I am curious with what engine and oil capacity Mobil 1 EP was based to last 15,000. Surely not a 4 cylinder with 3.5 qts. of oil. But it would make sense that the fact there is more oil that there is more additives and protectants in the oil.
Extended OCIs = Oil Capacity?
- Thread starter Buford T. Justice
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It's a design decision. Using a bigger pan isn't as simple as it might seem and involves some other tradeoffs.
The mfrs have design standards that require a reliable oil supply to the pump under various conditions of acceleration, braking, cornering, hill and side slope operation with oil at the add mark. They also require that that oil not get whipped by the crankshaft when oil is at the full mark under similar conditions.
To meet those requirement without going to a dry sump, you often need a deeper pan as well as a wider/longer pan. That in turn requires raising the engine in the car which has an impact on drivetrain design and maybe the front structure of the car.
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This was my assumption. I knew that the more hyper Euro alloy had larger sumps and spec'd rather sophisticated advanced oils. That's the only way that I could figure them getting the long drains. I thought that a comparison by plugging in your equation (backloading it, if you will) we could get a correlation between the spec'd OCIs that they're seeing ...and what your equation would yield (with the aforementioned "fudge factor" applied).
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So ..go conservative and round down. You don't use dino (my guess) ..so 6k 10k
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Hmm..I wonder if TS has an HDEO modifier to the equation
Shear stable, good initial TBN, long drain .....
I wonder if it would get an honorary 80 "C" factor???
I wonder if it would get an honorary 80 "C" factor???
didn't wanna look silly but I was thinking the same thing.quote:
Originally posted by Gary Allan:
Hmm..I wonder if TS has an HDEO modifier to the equationShear stable, good initial TBN, long drain .....
I wonder if it would get an honorary 80 "C" factor???
TS did a nice job of putting that equation together but you can still use your own judgement to tweak his finagle factors. Take a swag at where you think HDEO would fall relative to the other oils and assign your own number to it.quote:
Originally posted by Gary Allan:
Hmm..I wonder if TS has an HDEO modifier to the equationShear stable, good initial TBN, long drain .....
I wonder if it would get an honorary 80 "C" factor???
TS did a nice job of putting that equation together but you can still use your own judgement to tweak his finagle factors. Take a swag at where you think HDEO would fall relative to the other oils and assign your own number to it.
Sorta like I peel away the mpg fru-fru from the equation and calculate gallons burned before an oil change instead of guessing at MPG over the period of an oil change. I also ignore the power density number, but would consider doing something there if I had a turbo.
I plan to see where his equation falls vs my OLM and UOA.
Duplicate
I like TS's equation and IMO it's a good estimating tool. I don't care for the explanation about the power density addressing the driving style pursued by high-performance-car drivers. In reality, that explanation has nothing to do with it for the reasons XS650 points out. What it does do as far as I can see, is compensates for the stress levels of a particular engine. Thus, a typical American-style 'performance' engine, whose power density is somewhat lower than many imports, would see a relatively longer OCI, whereas a high-stress, modified turbo SAAB would have to go relatively shorter.
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I've thought about that a little ..and I may have missed some of the counter points that may alter my perception here ..but I think the fuel economy
ower density:displacement triad compensates well.
I'm sure it has some holes in it ..but it's not a bad place to start. It works well with my tractor engine (4.0/2.5 jeep) ..and appears sensible for my 3.0 Mitsubishi. This may have more to do with the sensible features of automotive engineering having certain conventions that are shared somewhat across the board.
ower density:displacement triad compensates well. I'm sure it has some holes in it ..but it's not a bad place to start. It works well with my tractor engine (4.0/2.5 jeep) ..and appears sensible for my 3.0 Mitsubishi. This may have more to do with the sensible features of automotive engineering having certain conventions that are shared somewhat across the board.
What about the presence of an oil cooler, that doesn't seem accounted for at all.
Counterpoint was that it's the power you are using, not the potential power in the engne. The power you use is already considered because it's a change oil at x gallons of fuel consumed equation.quote:
Originally posted by Gary Allan:
I've thought about that a little ..and I may have missed some of the counter points that may alter my perception here ..but I think the fuel economy
I think TS did have a good point about turbos being harder on oil, but except for turbos the power density finagle factor doen't make sense doesn't make sense. A 240 hp 2 liter Honda S2000 doesn't need it's oil changed twice as often as a 2 liter 120 hp Accord just because the S2000 can put out twice as much hp/in^3.
A 1.1 hp/in^3 Corvette is easier on oil than a 1400cc 0.8 hp/in^3 S'Box that gets it neck wrung to keep up with freeway traffic everyday.
I still think it's the best oil change calculation I've see if you off the power density.
Valid point, but some place you need to stop complicating it. Oil temperature would be even better, some cars with oil coolers run thir oil hotter than some cars without them.
So I guess this means that the 5 cylinder non-turbo in my little Volvo S60 that holds about 6 quarts would be an ideal candidate for long OCI's. Nothing but 30 easy freeway miles every day (no congestion either) What other cars out there have high sump to power/engine ratio. I have to admit I was surprised when I realized that my little commuter Volvo took more oil than my wifes new 2006 Toyota Sienna V6.
Ah but my car is turbo charged remember so it is actually cooling the oil.
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Well ..help me out where I lost you. I understand you in concept ..and I'll agree with the fuel consumed thingy ..but I reread your original objection to the mpg factor and your equations appear to use the ^3"/hpquote:
Originally posted by XS650:
Counterpoint was that it's the power you are using, not the potential power in the engne. The power you use is already considered because it's a change oil at x gallons of fuel consumed equation.quote:
Originally posted by Gary Allan:
I've thought about that a little ..and I may have missed some of the counter points that may alter my perception here ..but I think the fuel economy
I think TS did have a good point about turbos being harder on oil, but except for turbos the power density finagle factor doen't make sense doesn't make sense. A 240 hp 2 liter Honda S2000 doesn't need it's oil changed twice as often as a 2 liter 120 hp Accord just because the S2000 can put out twice as much hp/in^3.
A 1.1 hp/in^3 Corvette is easier on oil than a 1400cc 0.8 hp/in^3 S'Box that gets it neck wrung to keep up with freeway traffic everyday.
I still think it's the best oil change calculation I've see if you off the power density.
Plug in some numbers and try it.
Take C=80, Sump Capacity = 5.5 qts, in^3/HP = 0.91
Simple way.
Gallons of fuel burned = 80 x 5.5 x .91 = 400.4
Complicated way.
Miles = 80 x 5.5 x 26 x .91 = 11410.4 miles
10410.4 miles/26 mpg = 400.4 gallons.
I'm really tired ..but I can't see how to get to 400 gallons of fuel without using that .91 figure there
Or are you mainly saying that even though we need to use it ...that you don't think that it's an accurate factor
I really shouldn't post when I'm this tired.
Just leave the power density factor out in both cases, now go get your beauty restquote:
Originally posted by Gary Allan:
Well ..help me out where I lost you. I understand you in concept ..and I'll agree with the fuel consumed thingy ..but I reread your original objection to the mpg factor and your equations appear to use the ^3"/hp
Plug in some numbers and try it.
Take C=80, Sump Capacity = 5.5 qts, in^3/HP = 0.91
Simple way.
Gallons of fuel burned = 80 x 5.5 x .91 = 400.4
Complicated way.
Miles = 80 x 5.5 x 26 x .91 = 11410.4 miles
10410.4 miles/26 mpg = 400.4 gallons.
I'm really tired ..but I can't see how to get to 400 gallons of fuel without using that .91 figure there
Or are you mainly saying that even though we need to use it ...that you don't think that it's an accurate factor
I really shouldn't post when I'm this tired.
Simple way.
Gallons of fuel burned = 80 x 5.5 = 440
Complicated way.
Miles = 80 x 5.5 x 26 = 11440 miles
11440 miles/26 mpg = 440 gallons.
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Okay ...now that I've had 7 under my belt. .91 is close enough to 1 to work. Gosh I get simple sometimes.
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