RLI BioSyn SHP 0w-30, 4760 mi, 1996 BMW M3

[d00df00d]

Been looking forward to this for a while.

Quick summary of the OCI:

- About 4 months and 4760 miles; I sampled early to compare with the previous UOAs, but that turned out to be a good thing with the TBN depletion.
- Driving was largely suburban roads and highway, with one ~900 mile road trip; some stop-and-go in summer heat.
- I have had a slightly heavier foot on cold starts lately (since they are not as cold during the summer); a fair bit of throttle but never over 2500 RPM until coolant is at operating temp.
- Lots of WOT, but not much redline on this run. I'm ashamed to say I rarely exceeded 5,000 RPM.
- Oil consumption is the lowest it's ever been with this car: about 1 qt/1500 mi. Motul 8100 X-Max 5w-30 matched this; every other oil I've tried fell far short.

Evidently fuel dilution was the worst it's ever been, which is likely one reason for the smaller remaining TBN and almost dangerously low flash point. Despite all that, this home-grown 0w-30 still managed to match or beat a race-bred big-name 5w-40 (Motul 300V) in a high-mileage engine that tends to prefer thicker oils. I will probably try the 5w-40 HD on the next OCI, but I think I'm pretty set on RLI for the foreseeable future.

What I'm not looking forward to is trying to look for and replace leaky injectors (the likely culprit for my fuel dilution) on a grad student budget. Ugh.

Anyway, report below. The current sample is the top row.

Previous samples, in order from top to bottom (click for threads):
Motul 300V 5w-40 #2
Motul 300V 5w-40 #1
Motul 8100 X-Cess 5w-40
Motul 8100 X-Max 5w-30 (original formula)

 

[BeanCounter]

Ideally, what kind of mileage are you trying to get out of your oil?

 

[d00df00d]

Once I fix the fuel dilution and settle on an oil, I'm going to take it out as far as it'll go.

 

[dparm]

I take it you'll be sticking with that oil?

 

[dcoyne78]

Keep in mind that the virgin RLI 0w30 has a starting TBN of around 6, you will do much better with the TBN of the 5w40 HD which starts at around 12 in its unused state.

 

[bluesubie]

I think the oil did pretty good for the conditions and the fact that it's a 30 grade. And I was surprised when you said you were switching to this instead of the RLI 5W-40 HD.

Did you get a uoa on the Motul 0W-30?

-Dennis

 

[d00df00d]

Originally Posted By: dparm
I take it you'll be sticking with that oil?

Nope. Switching to the 5w-40 HD per my first post.

The 5w-40 HD is a much more robust oil that should allow longer OCIs. The 0w-30 is an "energy conserving" oil that is optimized more heavily for reduced friction. One of the reasons I wanted to use the 0w-30 was so I could share an oil with my brother and save some money on bulk orders, but it seems possible that the 5w-40 HD is just better suited to what I want. If I didn't want the longest possible OCIs, I'd stick with the 0w-30.

 

[d00df00d]

Originally Posted By: dcoyne78
Keep in mind that the virgin RLI 0w30 has a starting TBN of around 6, you will do much better with the TBN of the 5w40 HD which starts at around 12 in its unused state.

Good call. I didn't know this going in (the spec sheet for the 0w-30 doesn't list TBN).

Incidentally, if it started at 6 and all that fuel dilution only brought it down to 3.4, I'd say that is some darn good TBN retention...

I really would have loved to stick with this oil. Maybe I'll come back to it if I can fix my fuel dilution.

 

[d00df00d]

Originally Posted By: bluesubie
Did you get a uoa on the Motul 0W-30?

I presume you're talking about 8100 X-Lite 0w-30. Correct me if I'm wrong.

I never got to try that oil in my engine. Would have been interesting for sure.

 

[bluesubie]

I guess I confused x-max and x-lite.

-Dennis

 

[d00df00d]

Ah, okay. Yeah, click the link in the OP at the bottom.

 

[dcoyne78]

RLI also makes a 10w30 HD oil which would not be as energy conserving as the 0w30, but it might be a compromise between the 5w40 and the 0w30 which would work ok in warmer weather. In a cold climate the 5w40 would give better flow at startup in winter.

 

[d00df00d]

Yeah, I was thinking about that. I figured if I'm not going to go for a super slippery oil, I'm going to go all the way and get their 5w-40 HD, which apparently has other goodies above and beyond what their other HD oils have.

 

[d00df00d]

Just realized this thread needs an update.

A few weeks ago I bought a set of used injectors, had them professionally rebuilt, and installed them. Afterward, I took a test drive without resetting the ECU just to see what would happen; I figured that if any of the old injectors were leaking, the new ones would cause those cylinders to run lean at first, and I might get a CEL. Lo and behold: 5 minutes into the drive, misfires on cylinders 5 and 6. I cleared the codes and reset the fuel trims, and it's been smooth sailing since then. The engine definitely runs more smoothly, starts more easily, and responds more eagerly. I think it's safe to say at least some of the old injectors were leaking, and that was causing at least some of my fuel dilution.

It's too early to judge oil consumption, but watch this space...