Oil Analysis - 1st oil change

[getbent]

I still don't think NOACK is terribly important unless you have issues with intake valve deposits or significant oil consumption as you are referring to. The NOACK test is at 150C which is significantly hotter than operating temperature. I would honestly be surprised if oil consumption was significantly impacted by NOACK unless used in extreme enviroments like racing.

I believe HTHS is rated in cP or cSt rather than percent, but I get what you are saying. I have yet to see a reason to run a thicker oil (whether it be 100C viscosity or HTHS) in a unmodified FA20. Even the UOA's with significant shearing seem to have low wear.

I used to own a 2005 Subaru Legacy GT and ran M1 5W-30 for the first 60K and Rotella 5W40 for the next 60K. It never burned enough oil between changes every 3500 miles to even bother topping it up. I sold it at 120K with the original engine and turbo but did have to get the clutch replaced due to a noisy throwout bearing.

[L3P47]

Getting my first oil change next week. The dealer gives you the 3 free of course but I just can't wait 7500 miles. Top will be every 3500.

[bluesubie]

Originally Posted by getbent

I used to own a 2005 Subaru Legacy GT and ran M1 5W-30 for the first 60K and Rotella 5W40 for the next 60K. It never burned enough oil between changes every 3500 miles to even bother topping it up. I sold it at 120K with the original engine and turbo but did have to get the clutch replaced due to a noisy throwout bearing.

Sorry but you drive way too conservatively and responsibly!

My FXT burned through one quart of Mobil1 0W-40 (spins at 3,500 rpm's at 80 mph) on a spring trip from NJ to SC. UOA just posted at bitog.

-Dennis

[smbrm]

Originally Posted by bluesubie

A high VI means the oil is less prone to shearing and is lighter in freezing temp start-ups.
-Dennis

Dennis, I struggle with this comment in isolation. Whether something shears or not is dependent on its shear stability, not its VI. VI only tells you about the rate of change of kinematic viscosity with temperature. If you only had a VI value it would not tell you much about how thin an oil was at any particular temperature.

The last time I was aware, low temperature CCS and MRV viscosities were the most relevent characteristics to low temperature performance.

[bluesubie]

Originally Posted by smbrm

Dennis, I struggle with this comment in isolation. Whether something shears or not is dependent on its shear stability, not its VI. VI only tells you about the rate of change of kinematic viscosity with temperature. If you only had a VI value it would not tell you much about how thin an oil was at any particular temperature.

The last time I was aware, low temperature CCS and MRV viscosities were the most relevent characteristics to low temperature performance.

Disclaimer:
I'm not a chemist and I don't play one on TV.
A high VI does tell you about the rate of change of kinematic viscosity and a higher VI usually, but not always, gives you an indication how light the oil is in freezing temps but isn't a measure of actual KV. MRV viscosities are useful at what? -35 or -40C? And MRV doesn't do you any good if you do not know what it is since it's less common to be listed on a PDS.

I'll just go with the ASTM definition of VI to avoid confusion:

Significance and Use

The viscosity index is a widely used and accepted measure of the variation in kinematic viscosity due to changes in the temperature of a petroleum product between 40 and 100°C.

A higher viscosity index indicates a smaller decrease in kinematic viscosity with increasing temperature of the lubricant.

The viscosity index is used in practice as a single number indicating temperature dependence of kinematic viscosity.

Viscosity Index is sometimes used to characterize base oils for purposes of establishing engine testing requirements for engine oil performance categories.

But you're right, a high VI alone doesn't necessarily tell you how light an oil is at any given temp. If you don't have the MRV specs, a better indicator is just to plug the 40C and 100C numbers into a viscosity calculator. Of course a 0W-x isn't necessarily thinner than a 5W-x either.

-Dennis

[getbent]

Originally Posted by bluesubie

Sorry but you drive way too conservatively and responsibly!

I towed a 2500+ lb enclosed motorcycle trailer (loaded) many times, some of which were 4+ hour trips each way and it made no difference to oil consumption. Is that your definition of conservative?

I don't think its safe to assume that every car burns oil equally. I'm sure there are FA20's out there that burn lots of oil, but there many that don't burn any noticeable amount.

What is your take on why the FB20's tend to burn oil? Rings, oil too thin, valves?

I also owned a 2000 Legacy GT Wagon with the EJ25D, bought it used with like 120K miles. It had horrible piston slap and burned copious amounts of oil. Oil weight seemed to make little difference in the piston slap or consumption rate.

[smbrm]

Originally Posted by bluesubie

Disclaimer:
I'm not a chemist and I don't play one on TV.
A high VI does tell you about the rate of change of kinematic viscosity and a higher VI usually, but not always, gives you an indication how light the oil is in freezing temps but isn't a measure of actual KV. MRV viscosities are useful at what? -35 or -40C? And MRV doesn't do you any good if you do not know what it is since it's less common to be listed on a PDS.

I'll just go with the ASTM definition of VI to avoid confusion:


But you're right, a high VI alone doesn't necessarily tell you how light an oil is at any given temp. If you don't have the MRV specs, a better indicator is just to plug the 40C and 100C numbers into a viscosity calculator. Of course a 0W-x isn't necessarily thinner than a 5W-x either.

-Dennis

I appreciate what you are saying, however even in the absence of no other information it still only tells you what it tells you according to the definition that you quote, which isn't much in my experience. CCS and MRV viscosities are very important dynamic low temperature tests that are defining in terms of viscosity grade specifications and more relevent to product differentiation if they are chosen as a route to differentiate engine oils. They tend not to get reported because despite a lot of trying, they have never been of interest to most average consumers where selecting the viscosity grade and the appropriate API/ILSAC specifications is all that most people want(if that) or need to know. They usually don't get reported as this allows competitors to easily nit pick each other on product performance capability.

[bluesubie]

Originally Posted by getbent

What is your take on why the FB20's tend to burn oil? Rings, oil too thin, valves?

I really don't know since I read a couple of comments from Subaru techs claiming that the engine was designed around 0W-20 (it's what they were told in class). Other manufactures have been producing engines that spec 20 grades for a while now.

-Dennis

[Khyron686]

Originally Posted by bluesubie

And here's a recent discussion about Pennzoil Platinum 0W-20:

http://www.bobistheoilguy.com/forums...gonew=1#UNREAD

I've only read a couple of replies, but of course a large focus in that thread is about PP's low Viscosity Index. A high VI means the oil is less prone to shearing and is lighter in freezing temp start-ups. Viscosity Index Improvers are also the first thing in oil to break down in oil and cause deposits.

IMO, the more important spec for a BRZ/FR-S is a low NOACK volatility number (measurement of evaporation). Platinum's NOACK is 8.9% while many oils are around 13% (if you can even find the NOACK). Lower is better.

And for those that live in the North Pole, a lower MRV means the oil is thinner at -40C.

-Dennis

So would you go Mobile 1 0-20 or Pen Plat 0-20 in Canada dead winter, 0 to -30C usually? How about for summer?

In the Jetta 1.8T I flipped between PP 5/40 and Castrol Syn 5/40 with good results.

[Ranatsu]

I've been running Pennzoil Ultra 5w20 since my first oil change at 3000 miles. I'm currently at 7200 or so with no oil consumption. On the dipstick the oil is still an amber color.

At 10k or 11k I will change the oil again and send it in for a UOA and see what we find.

[gmookher]

Originally Posted by bluesubie

And if the old Subie SM can't be found, there's a new Mazda high moly 0W-20.

-Dennis

Indeed.

[gpshumway]

Originally Posted by Khyron686

So would you go Mobile 1 0-20 or Pen Plat 0-20 in Canada dead winter, 0 to -30C usually? How about for summer?

In the Jetta 1.8T I flipped between PP 5/40 and Castrol Syn 5/40 with good results.

Mobil 1 has a superior (lower) MRV viscosity and a higher VI, so it's probably the best choice for Canadian winter.

Mobil 1 is also heavier at operating temp (HTHS of 2.7 vs 2.6), so it will also handle higher temperatures better. Canadian summer doesn't really qualify as hot, though, so PP would likely be fine. The real determining factor on high temps is usage (track), not air temp though it does play a substantial role.

The real question is which oil performs better 4,000 miles into the OCI. It's quite possible that PP handles fuel dilution better than M1 and would therefore maintain it's performance better than M1. The previous UOA showing a 375*F flashpoint points to some possibility of dilution in these cars. Without more UOA data we just don't know.

[gpshumway]

Originally Posted by bluesubie

And if the old Subie SM can't be found, there's a new Mazda high moly 0W-20.

-Dennis

A bit of a warning here. There are Subaru 0w20 bottles floating around labeled SM which don't have high moly levels.

Dennis-
Remember that Subie SM oil I bought a few months ago at my local dealer? (BITOG Link) Well, I just got a UOA back with it (in my Honda) and the moly levels are dramatically lower than the previous fill of the Subie SM. Like 280ppm instead of 560. I didn't do a KV40 on it, so we don't know the VI, but it's still in the car and I will do a KV40 when I drain it in March or April with ~6,500 miles on it.

Safest to just go with the Mazda oil at this point if you want the high VI and high moly.

I'll see if I have time tomorrow to post the UOA over on BITOG.

[bluesubie]

Originally Posted by gpshumway

A bit of a warning here. There are Subaru 0w20 bottles floating around labeled SM which don't have high moly levels.

Dennis-
Remember that Subie SM oil I bought a few months ago at my local dealer? (BITOG Link) Well, I just got a UOA back with it (in my Honda) and the moly levels are dramatically lower than the previous fill of the Subie SM. Like 280ppm instead of 560. I didn't do a KV40 on it, so we don't know the VI, but it's still in the car and I will do a KV40 when I drain it in March or April with ~6,500 miles on it.

Safest to just go with the Mazda oil at this point if you want the high VI and high moly.

I'll see if I have time tomorrow to post the UOA over on BITOG.

Sometimes I just don't know what to think about SoA and oil. When they incorrectly advised in an email newsletter that the Impreza specced "0W-30 conventional" (which doesn't even exist) I emailed a friend at SoA volunteering my services to proof read their oil info. He didn't respond. Then there's the owner's manuals that list "5W-40 conventional" as being acceptable for replenishment. The BRZ manual appears to have been written by Toyota.

When the Subaru oil first came out they did not even label it with the API or ILSAC spec! You can probably even find pics of the old bottles on line. When I emailed SoA in September of 2011 to ask when the oils would be switching to SN/GF5, they didn't have any info. Any oil made from October 2011 onwards that gets the API Starburst must meet SN/GF5.

Maybe your oil wasn't blended at the lab correctly. You can always email Idemitsu for information.

-Dennis