BMW N55 Turbo-charged Engine Oil

[JAG]

Today I test drove the new BMW Z4sdrive35i which has the new version turbo-charged engine - N55. There is an older thread here about the previous version - N54 which discusses how the engine is hard on oil due to high oil temperatures and fuel dilution.

It is was around 92F during my test drive and the oil temperature got up to 252F degrees. The type of driving started with full-throttle bursts of acceleration between about 4 lights, then 2 minutes of highway (flooring it from the on-ramp), then back bursts of acceleration between a couple more lights. I've driven my BMW 135i (w/ N54 engine) harder/longer and the highest oil temperature I've seen is around 242F. I think this newer engine is going to greatly stress the oxidative and thermal stability of the motor oil. If fuel dilution is no better than in the N54 and sump sizes are equal or similar, it will be even harder on the oil. I'm surprised BMW did not develop a new oil spec or update their existing LL-01. It will be interesting to see the UOAs come in for these engines.

 

[d00df00d]

Originally Posted By: JAG
I'm surprised BMW did not develop a new oil spec or update their existing LL-01.

My sentiments exactly. I'm having a hard time imagining how the new DI turbo engines aren't critically game-changing for a lubrication spec initially developed in 2001. Maybe it's not a problem in Europe, so they don't care?

It would be really nice to hear from a BMW engineer on this.

 

[dparm]

What's the factory fill on that motor?

 

[JAG]

I don't know what the factory fill is but I'd wager that it meets the BMW LL-01 spec.

 

[bmwtechguy]

Factory fill on that engine and most BMW engines is now some type of Castrol 0W-30. I have no way of knowing if this is the same GC oil we can buy here. I sort of doubt it.

 

[saaber1]

I want on of those cars! Stunning!

Re: the oil, 252 degrees, Cripes!

Reminds me of this Dyson quote:

Originally Posted By: Terry
reb03, I have customers running BMW5w30, M1 0w40 all with the same effect, the wear control is good if we change the oil at 1000 mile intervals but the deposit formation from REAL volatility issues are slowly damaging the engines. I just worked a 07 335 Biturbo yesterday USING ASTM lab tests on the used oil and M1 0w40 went from VOA flash of 430+F to 280 F in 1150 miles, oil sheared to 12.1 cSt and fuel was at 1.99% by IR.

Makes one wonder what a standard BMW approved PAO oil would look like in that N55 engine after BMW's recommended OCI. Scary!!!! I can imagine what the valves would look like after repeated runs with BMW OCIs and standard PAO oils...(shudder)

 

[saaber1]

BTW, I was thinking about why ester-based oils seem to do better in the WV/Audi 2.0 FSI DI turbo fuel diluting monster, and I was wondering is it the basestocks themselves that cause it to perform better or is it actually because the basestocks allow less viscosity modifiers to be used? To see that kind of volatility and shearing that fast (referring to Dyson's quote) it has to be shearing of the VII's right?

 

[Roy Gutfinski]

If that 252 F reading is correct, this engine is stressing the heck out of that oil. The engine needs an external oil cooler and/or auxiliary cooling capacity for the turbochargers. 1,000 mile OCI's are not going to cut it for a highway vehicle.

 

[dparm]

Where is this 252 number coming from? Do the cars actually have a readout?

Regardless, I'm sure BMW has tested this and knows. Does it still carry the 10k or 15k interval?

 

[m6pwr]

I've got an '09 z4 with the N54 together with a 7 speed dct. At 1500 mi I switched from BMW factory fill (their 5w-30) to German Castrol 0w-30 (BMW specifically "approves" the GC as an alternative to their oil and it meets LL-01). The GC I think is a slightly better oil with a slightly higher flash point and stronger AW additive pack (based on VOA's and UOA's I've done on other BMWs comparing the two). I recently added the Dinan Stage II performance software which ups the power on my N54 twin turbo di motor to 385 hp and 424 lb ft of torque. The car is scary fast. The motor does have an external oil cooler and so far oil temps (oil temp gauge) cycle between 230-250 F (considered normal by BMW for this motor) during spirited driving. I think the ecu-controlled electric water pump may also help with oil temps. I'm anxiously awaiting my first UOA on the GC at around 4500 mi. Blackstone UOA on the BMW factory fill at 1500 mi was very good considering engine was breaking in. Normal wear metals and no fuel dilution, and vis within spec.

 

[Craig in Canada]

Originally Posted By: JAG
I'm surprised BMW did not develop a new oil spec or update their existing LL-01. It will be interesting to see the UOAs come in for these engines.


Updating the oil spec is a bandaid. IMO, I'm surprised that BMW didn't fit all N55 cars with stout air-to-oil coolers to keep the oil temperatures under control. I guess they didn't learn lessons from the N54, or decided there were no lessons to learn. What are oil temps like on the autobahn without oil temperature control if this is what happens from a couple of on ramps?

Instead of developing and specing some crazy oils, just cool the oil directly like Porsche has done for decades. Heck, my 240hp 3.0L Porsche 968 had a ducted oil/air cooler.

 

[Oldwolf]

This is what Mobil says:

 

[dparm]

That's the old 3.0L, not the new 3.5L. Their site is wrong.

 

[Oldwolf]

Even the BMW website only shows 3.0L engines in the Z4's.

http://www.bmwusa.com/standard/content/vehicles/2011/z4/default.aspx

 

[BMWTurboDzl]

Originally Posted By: dparm
That's the old 3.0L, not the new 3.5L. Their site is wrong.


Actually it's correct. The isn't 3.5 liter I6 in BMWs current lineup. Both the N55 and N54 are 3 liter engines. M1 0w-40 is LL01 approved. The newest standard is LL04 however it's not compatible with the quality/make up of U.S. gasoline and therefore reserved for BMW diesels (LL04 isn't necessarily better, it's just Low-SAPS).

I would bet that the sticker inside the engine bay of a car equipped with the N55 would reflect a BMW oil part # which is 40w.

 

[Oldwolf]

They do talk about the N55 in this car though...
http://www.bmwusa.com/Standard/Content/AllBMWs/FutureVehicles/20113series/default.aspx

 

[dparm]

What the [censored] are they calling it the "35" for then? It's not even a 3.5L...

 

[BMWTurboDzl]

Originally Posted By: dparm
What the [censored] are they calling it the "35" for then? It's not even a 3.5L...
'330' was already taken since BMW launched the E90 with a 3.0l 255hp NA engine. The 335 moniker was supposed to reflect the additional power over the 330. The N55 has the same HP as the N54 (also named 335) but it's supposedly cheaper for BMW to build (twin scroll turbo vs. twin turbo), gets better fuel economy, has better reliablity (N54 HPFP failure prone).

My .02

 

[shortyb]

Originally Posted By: bmwtechguy
Factory fill on that engine and most BMW engines is now some type of Castrol 0W-30. I have no way of knowing if this is the same GC oil we can buy here. I sort of doubt it.


I've heard the same thing. Wouldn't doubt that its a "special" formula 0W-30, Castrol has 5 that aren't available here in the US. BMW 5W-30 has gone through 2 minor formulation changes but nothing to address fuel dilution or deposit control of the newer D/I turbo engines. Still waiting for ACEA to come out with their oil sequence ratings ( based on the CARS 21 regulations) before BMW does anything with an updated LL spec.

 

[m6pwr]

There will be an added dimension to this topic soon when the next generation of M cars comes out with turbocharged di motors. It will be interesting to see if BMW comes out with some sort of M-specific oil (I don't think it will be Castrol TWS 10w-60) for these motors or simply specs the current BMW High Performance 5w-30. It will also be interesting to see what oil temps these motors run.