Great link, lots of good distilled info there. The whole Ester/Motul issue is covered well if you read through it. Basically, they're saying Motul-like oils look great on paper and probably perform great in racing applications (high heat and stress, not much time sitting around the garage oxidizing), but that in a consumer application where the oil isn't heated up and gets to sit around oxidizing more, it may convert itself into a worse oil. This sounds like something that (a) probably is true for many daily-drivers, and (b) is probably highly dependent on individual patterns in driving, mileages, storage lengths (is it often left garaged for days?), local weather, etc, etc..

I'm a little suspicious of the overall graph you pasted, in that it seems that the mean (and deviations) being measured against are going to be heavily influenced by the existing popularity of various brands of oil among those contributing UOA's, since the mean is based on total samples received. It might be interesting to re-run the numbers by first averaging together groups of samples of the same brand/type, then deriving the mean by averaging those numbers together (so that they aren't popularity-weighted).

Still, thanks for posting that, it's very useful information. I'm still going with the Motul on my next change, so we'll get to see how the UOA goes in my case.

Hey wstar, how far off is your next change? I just crossed over the 2000 mile mark, so at this rate, I won't be doing my next change until August.

The smaller the sample, the more suspect the numbers. Torco was only used by one person, and that could've been a newer car still in the break-in phase, we don't know.

It would be much more relevant to calculate standard deviation per motor-oil, but that wasn't done because the results would look terrible. The small samples are completely understandable since the creator (Resolute?) only had access to UOA's submitted by forum members, and the effort was pretty cool considering the effort involved. Still, the results are not reliable for most brands.

:iagree: The sooner we run out of oil, the sooner these arguments will finally be put to rest.

I just crossed over the 3100 mark. I'm kinda torn between waiting for 5K (the whole "finish breaking in on dino oil" thing), versus just doing it at say 4K (so that will be 1800 on my factory oil then 2200 on the Nissan Ester I put in, then straight to synthetic). Knowing me, I'll probably go ahead and pull the trigger shortly after 4K. It can't be that big a difference anyways, and I think I've done a good job breaking it in so far all over the RPM range, including one rather loud and fun late night drive where I ramped up and down around 5-7K RPM on the freeway for long enough to get the oil up around 255. If anyone had been around (it was empty) they would've thought I was crazy :)

It figures, it never fails, I pitch a bitch, and the tables get turned! I just got the e-mail, it's on it's way, via UPS!:happydance:

So back on the statistics stuff, as some of us have already pointed out, while the table from that 350Z thread is really nice work, it's also too small a sample size to draw any real conclusions from. Some of the data values are suspicious relative to each other as well, probably due to different analysis companies and different tests run (granularity of the data, and some zeros seem to really be missing data). It's really too small for statistics for that matter, but we have to do what we can with what little data we have.

All that said, I re-ran the numbers from that graph through a Google Docs spreadsheet, and I recalced the red/green squares like I described before just to see what kind of difference it makes. As expected, there are fewer of both reds and greens when the popularity effect is cancelled. Especially in such a small sample, this popularity effect made a big difference in both the average and the standard deviation (4 samples of Syntec vs 1 sample of 300V for example. Imagine if it were 40 to 1, and how that would affect which ones get flagged as statistical outliers).

The following is basically the same as the original (red = 1+ std dev high, green = 1+ std dev low), but the mean and std dev are based on using the averages of each oil type, rather than looking at all raw samples, so that the oils are on the same footing regardless of popularity. You'll see some of the same trends, but there aren't nearly as many reds, and hardly any greens. Mostly the widening of the deviation just re-iterates how little we know statistically speaking about these oils. Any of these samples could be complete flukes. Anyways:

http://www.the370z.com/members/wstar...ty-effects.png

ETA: That's about as much as I'm willing to mess around with it, but really you could go further in making it "fairer" by grouping the ones that are based on similar formulations. The fact that some formulations are sampled in multiple weights distorts everything too (see # of Mobil1 columns vs # of Eneos columns, for example). We've got so little data to go on though, the rewards of further re-analysis are pretty slim.

Here's the oil analysis thread on the VQ35HR. 2007 VQ35HR Engine Oil Analysis - MY350Z.COM Forums

Actually, it may be coming even sooner than expected now. I just met a really cool girl, been on a couple of dates. It's going really well, and she lives way on the other side of town, it's about a 35 miles each way. My mileage per week is about to skyrocket :)

:bowrofl: That's awesome, man! Congrats. Oh btw, :pics:

And I'm not talking about your car either. :rofl2:

:worthless:

Sorry to disappoint, but I've seen how this goes on other forums. 3 pages from now someone will have traced the picture back to her myspace account, figured out all of her personal info, and be calling her and harassing her. No thanks :)

Dang it! Foiled again.

Ok, ok, here's a pic (of my blackstone oil analysis kits that came in today ;)):

http://www.the370z.com/members/wstar...lysis-kits.jpg

Hopefully these will give us some insight on the whole Motul issue in the future.

I'm gonna do this too. The more data points the better. Are you getting an analysis done on your next drain? (i.e., the Nissan Ester Oil) I think I'll do one on my next drain, which will be the Nissan oil, then again the first time I drain the Motul.