N52 Engine Oil

[Taymaishu]

I've been searching around the forums for a few weeks now on the engine oil saga and haven't really found much at all.

A couple of weeks ago i receved a low engine oil light (turned out to be false positive as i was parked on a slope). Regardless, i went to purchase a litre of oil from the servo just in case. I endedup gettin Mobil 1 SyperSyn 0W-40, pretty much the top Mobil oil you can purchase.

I called BMW Assist to make sure all would be OK and they said for the N52 they recommend a 5W-30. So my thoughts were that the 0W-40 would protect perfectly, but perhaps the difference viscosity may not be that good. BMW Assist kindly said it would be fine.

Just wondering if anyone's using the 0W-40 and how they find it compared to the OEM oil? My car is in for service (privately) on Thursday. My mechanic races and develops V8 engines and said he as the 0W-40 in stock if i want it on the oil change.

[Taymaishu]

Originally Posted by TrackRat

The Mobil 1 0W-40 is fine as long as what's sold in your locale is BMW approved for your engine - which it should be. The OE oil is 5W-30 but the Mobil 1 0W-40 covers all of BMW's viscosity requirements for non-M gas engines. In the U.S. the Mobil 1 0W-40 is BMW approved.

http://www.bmwusa.com/Standard/Conte...ngineOils.aspx

Yeah it's ACEA-A3 and BMW LL approved.

Told my mechanic i'll go with the 0W-40.

[AussieRacer]

0W-40 will sap power compared 5W-30. Unless you are running it around a track for 5 plus laps, the oil won't get too hot, so stick with the thinnest oil recommended to keep power losses low.

Note: just guessing here about the number of laps, but hopefully you get what I mean. Eg a squirt through the mountains is no strain compared to a track lap at 80-90% where you are maybe on full throttle 60% of the time.

[Cruiser]

I am also looking to change to the 0-40W or otherwise 0-30W this week.
My daily commute is only 1.5 kms so the oil never heats up. So I especially want good startup protection.

[Taymaishu]

Originally Posted by Cruiser

I am also looking to change to the 0-40W or otherwise 0-30W this week.
My daily commute is only 1.5 kms so the oil never heats up. So I especially want good startup protection.

Hey Cruiser

Where abouts on the beaches are you!?

Well it's my 30k oil change and suddenly i won't be commuting to work from my new place (moving). Want something with good protection as my trips are going to be fairly short, just like yourself.

Pretty expensive though, i think it looks like around $110 for 6 litres.

[AussieRacer]

Originally Posted by TrackRat

Do you have any idea what the difference is in engine viscous drag between a 30 weight and 40 weight engine oil? 40 weight will not sap power from the engine. In controlled engine testing you'd be luck to measure a couple HP in a 500 C.I. race engine between a 20 weight and 40 weight oil @ 10,000 rpm. A 30 weight or 40 weight hot viscosity is just fine and I defy anyone to tell the difference in a blind test. Having actually dyno and track tested oils, I can speek from experience and objective test data.

Compared to a 30 weight oil, a 40 weight will sap power when only operating in a 30 weight oil temp range. Whether in a road car it is measurable or you can feel it after an oil change is pointless due to the many other variables. If you are trying to do the most appropriate action for the engine and extract every last ounce of power, using the correct weight oil is important.

As a side note, people come here asking for advise on the correct thing to do, and trying to prove a point with contradicting information to boast one's achievements/experience is also pointless.

[Cruiser]

Originally Posted by Taymaishu

Hey Cruiser

Where abouts on the beaches are you!?

Well it's my 30k oil change and suddenly i won't be commuting to work from my new place (moving). Want something with good protection as my trips are going to be fairly short, just like yourself.

Pretty expensive though, i think it looks like around $110 for 6 litres.

Lets just say I am not far from the store you have been plugging all day!

I am pretty sure I will either go the M0-40W or otherwise I want to check out the Motul8100 XL

http://www.motul.com.au/product_line...4stroke13.html

You have sure done a few ks in your first year! Good on you.
I take the other car mostly keeping my Ks nice a low as I plan on keeping the car a long time.

PS Glad you sorted out your repairs so quick.

Cheers

[AussieRacer]

Originally Posted by TrackRat

I'm sorry but your beliefs are not supported by facts. Telling people nonsense does not make it true and it's a disservice to people who want accurate technical information. If you want to believe that a 40 weight oil saps power, so be it, but it's complete nonsense.

From the link below you will note that the low shear viscosity of a 40 weight oil can be the SAME as the high shear viscosity of a 30 weight oil -- 12.5 (cSt) @ 100C, which is a typical operating temp for oil in normal service.

You should also look at the lab test graph of viscosity vs. temp to see that a 20W-50, 10W-30, straight 30 and 10W-40 all have very similar viscosity @ 100 C, the normal oil operating temp. As such the viscous drag difference between the oils at a normal operating temp of 100 C is almost unmeasurable, which is exactly what objective dyno and track testing confirm.

And to add insult to injury regarding your insistence on using 5W-30 vs. 0W-40, the 0W-40 oil has a lower cold viscosity so it pumps easier than the 5W as the link shows. So technically a 0W-40 oil has better viscous dynamics than a 5W-30 oil.

...and that's the way it is.

http://www.ideas4ag-ed.com/uploads/3..._viscosity.pdf

Or it is....

Don't use words like "nonsense" and then "almost unmeasurable" to spread myths. Those graphs (which are just manufacturer specs, not objective test data) show exactly what I was stating. Use the correct oil for your temp range, and it will give you the best protection and power compromise.

Of course the ratings are guides, and manufacturers may make products crossing over those ranges despite what the label says. The average consumer can only trust what the label says to ensure they use the correct oil for their temp range.

And regarding cold weights, having too low viscosity for your temp range can reduce the protection on initial startup by having insufficiently coatings. Manufacturers know this, and hence they'll pick the best range.

I don't doubt what your track testing has confirmed, but if you are a serious competitor you'll know that if you want to be and stay at the front in a competitive series, you'll run thinner oil during qualifying and then thicker oil for protection during the races. In fact in a certain control sealed engine series in Australia, some guys are running 0 or 10 weight hot oils in races to give themselves the extra edge, knowing well and good they have to rebuild more often. Whether the extra edge is measurable (could be only worth 0.01 sec per lap) is unimportant if the man lining up next you has the budget to get the best performance.

I'd say "The End", but that would just be checky...

[AussieRacer]

Nope they don't lie. "you'd be luck to measure", "almost unmeasurable", "Very similiar" and "almost identical" don't equal your prior statements of "If you want to believe that a 40 weight oil saps power, so be it, but it's complete nonsense.", "40 weight will not sap power from the engine" and my new favourite "Your statements are incorrect, misleading and baseless as the links and independent oil data I provided show.". Don't speak in absolutes when you know the data and reality don't support it, even if the differences are small (which I acknowledge and have all along).

You seen what happen you use a too light weight oil for too long outside its ideal/operating range? I suppose that's why oil manufacturers make different grades of oil- who would have thought?!?!?

And I think it was you that brought racing up....unless your reference to "race engine" and "tracking testing" wasn't actually a race engine, but rather an engine in a car used on the track, rather than actual racing. In which case it ain't actually technically a race engine.

Anyway let's agree to disagree and let anyone now silly enough to read this thread decide.