Best oil for BMW 335i N54 twin turbo?

[z917990]

Hey Folks. I'm a bit confused here. I'm not an engineer or any other kind of expert, but from reading the posts, it looks like the oil in the 335i bi-turbo must be changed every 1000 miles

! Yikes! Am I misunderstanding here? Is this the case if the 335i is driven normally (i.e. not on the race track)? I'm looking at maybe purchasing a 335i (I do not mind 5000 mile OCIs), but I will not if the engine destroys oil so readily. Thanks in advance.

 

[reb03]

Yes

 

[reb03]

Quote:

---

Is the 3.0 biturbo BMW engine direct injection like the RS4 V8?

---

Yes, the N54 335i engine has direct injection. Please excuse my previous "yes" post - I clicked reply instead of reply with quote.

 

[buster]

I'd like to see a straight grade in one of these engines. Something like a Amsoil ACD SAE 30 with no VII's. M1 0w-40 with a VI of 187 and HT/HS of 3.6 is using a lot of VII's. Even a 15w-40 or 10w-30 would be possibly more ideal. Any thoughts on that?

 

[glenncof]

reb03,

Hopefully you don't drive on the street like you do at the track so I think you have two different operating environments which should be considered. I can't see a 7.5K OCI and track being used as considerations at the same time.

Looking at these conditions independently to find good solutions is likely to be hard enough. I would try for the optimal in each and then look for conservative compromises after looking at usage pattern/experience complimented with lots of study.

 

[RustyH]

Reb03, I recently read a Car&Driver article on this BMW twin turbo. They also noted the very high temperatures. They questioned why BMW recommended its 5W-30 oil rather than the 10W-60 (Castrol TWS Motorsport) as in their "M" cars. I'm not sure I saved that issue, but is was within the last few months.

 

[G-MAN]

Quote:

---

Reb03, I recently read a Car&Driver article on this BMW twin turbo. They also noted the very high temperatures. They questioned why BMW recommended its 5W-30 oil rather than the 10W-60 (Castrol TWS Motorsport) as in their "M" cars. I'm not sure I saved that issue, but is was within the last few months.

---

BMW made the same mistake with the M3 when it was first introduced in the US market. Once these twin turbo engines begin to self-destruct they will probably start recommending the Castrol 10w60.

 

[reb03]

Quote:

---

Reb03, I recently read a Car&Driver article on this BMW twin turbo. They also noted the very high temperatures. They questioned why BMW recommended its 5W-30 oil rather than the 10W-60 (Castrol TWS Motorsport) as in their "M" cars. I'm not sure I saved that issue, but is was within the last few months.

---

Yeah I have that C&D and the BMW Car Club's own Roundel magazine made similar comments. I also know of a few guys who run the 10w60 Motorsport oil in their 335s (same oil I used in both my E46 M3s) but I'm concerned the oil is too thick to properly lubricate the turbos. One person I know of claims significantly cooler oil temps using the 10w60 so I'd love to try it but I'm concerned about a voided warranty should something go wrong. If something in the engine goes with BMW 5w30 in there I'm fine but if something goes with 10w60 Motorsport oil in there then I bet they'd point the finger at the owner and simply say "sorry" the warranty is voided. But then again, I suppose putting RLI Biosyn, Red Line, RP, PP, GC or any of the others in there would do the same thing...

 

[RI_RS4]

Quote:

---

Is the 3.0 biturbo BMW engine direct injection like the RS4 V8?

---

Yes, it uses piezoelectric injector that has an even higher pressure than the VW/Audi system.

 

[Bobert]

How long do you plan on keeping the car? If you only plan to keep your car until 150k or less just buy some D1 or M1 TDT 5w-40 and change every 5k. No muss, no fuss, and no need for special concoctions.

 

[Terry]

Bobert, Eats HDD oils too, we tested that theory..... XOM did not do well in my testing....

 

[RI_RS4]

Quote:

---

Yes I know that a good high temperature test result does not mean that the oil will perform well in an engine. But I think you will agree that a very bad high temperature test result (320F...not insanely hot and wasn't tested for very long) does not bode well for performance in a hot running turbocharged engine.

---

JAG, you really need to do a "real" test. My engine has been running 5W-40 BioSyn for over 15K miles. During that time it's seen 10F to 105F ambient temperature, local stop and go driving, multiple cold starts during winter days after full cold soak, long trips during the summer at 105F, and 5 hours of track time at Lime Rock and Watkins Glen.

My normal engine oil temperature ranges between 212F to 235F on the street. On the track the oil temperature ranges between 250F and 275F when the engine is under severe stress under full horsepower at 8,000 rpm. UOAs show no oxidation, no soot, no viscosity shear beyond the initial shear, no additional acid formation, no combustion problems or deposit formations. Finally, visual inspection of the cam shaft through the oil fill shows no varnish buildup.

This engine has 31K miles on it, with the last 16K miles of runtime on the engine using RLI BioSyn. The current oil has been in the engine for 5,700 miles and just came back from 2 days at Watkins Glen. Iron wear rates (not just ppm levels) are running 2x to 5x lower than Audi 502 approved oils, and have been continuously since BioSyn was introduced.

Here's a picture of a cam lobe taken through the oil fill in the valve cover. Note, the valve cover is a funky yellow plastic composite.

What more could you want? An expert opinion from an independent expert tribologist who's been practicing for 30 years? Oh wait ... we have that, too!

 

[G-MAN]

Quote:

---

This engine has 31K miles on it, with the last 16K miles of runtime on the engine using RLI BioSyn. The current oil has been in the engine for 5,700 miles and just came back from 2 days at Watkins Glen. Iron wear rates (not just ppm levels) are running 2x to 5x lower than Audi 502 approved oils, and have been continuously since BioSyn was introduced.

---

You've got the RLI straight 40 in there now, right? How are the wear numbers on that looking compared to their 5w40?

 

[Lonnie]

And is that 30k miles in one year on a car that's tough on oil?

 

[reb03]

Quote:

---

And is that 30k miles in one year on a car that's tough on oil?

---

And LOVES premium unleaded. RI_RS4

 

[RI_RS4]

G-Man, wear numbers are identical.

Lonnie, 31K in 13 months.

reb03, yep, about 2000 gallons of premium unleaded at my average mileage.

 

[Lonnie]

RI_RS4 you are going to drive right off your warranty pretty soon. Do you have the extended warranty? I think if I had one of those BMW oil cookers I'd invest in the extended warranty. It looks like you'd have to have that to sell the car after a co couple of years boiling oil.

 

[e36'n]

Quote:

---

I asked the BMW 335i customer to post his Dyson raw data here and chime in, whether he is crazy enough to do that I can't say.

The raw trended data will scare you straight.

---

I'd definitely like to see those and pass them on to the FI BMW community.

As for JAG's tests, is he not proving anything useful at all?

 

[RI_RS4]

Quote:

---

As for JAG's tests, is he not proving anything useful at all?

---

Alright, I will try to not be funny and make light of what JAG has posted.

JAG needs to tell us what he has "proven". So far what we know is:

1) he has heated up oil to 340F in an open anodized aluminum cup on a hot plate.

2) he poured it on notebook paper and allowed it to absorb into the paper

3) he has observed that during this process something does not absorb into the paper

4) he did not chemically analyze what that "something" was

5) he does not know where that "something" comes from, whether it is in the oil or an external contaminant.

6) he did not determine if that "something" has properties that are good or bad.

He has certainly made a large number of assumptions, and has some theories based on zero knowledge of the BioSyn formulation.


So, what did JAG prove?

 

[JAG]

I do appreciate the honest attention given to what I found.
That's a huge hurdle passed.
The only significant things I believe I can say I found are that
1. Globules were found floating in the oil at the end of test
2. They were very resistant to absorbing onto the notebook paper
3. They were the clear spots seen on the notebook paper

I did not allow any external contamination on my part.

I've admitted I can't explain the finding. I will take back my earlier comment that the finding was very bad as I should have said "very odd". Any unsuspecting person in my shoes would have thought the same way. Maybe these globules have a good purpose? I don't know.

Similarly strange things have been seen in the past. For example, Auto-RX has floating particles in it when new. You can see and feel them. I have tested Auto-RX in many ways and found some unexpected things.

I want to just move on with this matter, so want others to move on past it as well. Go ahead and try the RLI oils and get UOAs done.