Kamran

Anyone knows why the ppm levels drop after usage? I understand the other metals decompose and are consumed, but why are phosphorus and zinc being consumed and drop their ppm levels?

Blackstone says they level off after the initial drop but don't know why they drop in ppm? If they are being consumed, then why would they level off... and then, again the same cycle with the next oil change?

fnbrowning

That type of deep dive into oil chemistry is best discussed with the oil fanatics at bobistheoilguy.com.

Kamran

I'm trying to establish a base line understanding of what make Vette engines tick, especially since I've never used Mobil 1 before (been using Motul 300V in my past vehicles).
After only 1,200 miles and a single trackday, phosphorus and zinc each dropped 200ppm in content. Although Blackstone says they'll level off, I find the drop a bit alarming. On the other hand I understand why 15W50 has so much higher content than 5W30. These two addetives are what protect the engine at hi temps. My concern is even if my oil test shows good remaining life, but these two levels drop, engine may not be safe. I'd like to understand what should be the pho & zinc threshold for a Vette engine? That d then tell me how many trackdays oil is good for, before the levels drop below threshold.

djnice

Man I don't think engines are that much different in this respect. The track guys I have talked to about this don't use Mobil 1 for this reason. Why don't you just keep using better oil like Motul?

xxaarraa

Interesting, thanks for sharing OP.

Increasingly becoming less and less impressed with Mobil 1 in recent years. For a number of reasons.

Kamran

In a recent oil testing Mobile 1 ranked below average. One of the issues facing big oil companies is, once they are on the radar, they have to limit Phos and zinc due to environmental regulations. If you look at Mobil 1 Race oil, it's a whole different animal, cost way more and has about 50% more phos / zinc. Unfortunately, you can't even use the race oil because it'll damage the cat.

From what I understand, you can still buy the extended performance oil in higher grades in Europe with hi phos zinc content, but not here. The only way I've heard you can buy that stuff here is in 55 gal barrels!

I so wanna go back to my Motul300V but with all the GM scrutiny to honor warranty I'm reading about on this forum, I'm very hesitant. Once my warranty is up, it's a different story, that is if I am not tempted by mid engine C8!

djnice

Does GM require Mobil 1 for warranty? I don't even think they require dexos. It's just recomeneded. Right?

Kamran

Well, know of any better oil that's Dexos?

X25

I've used Mobil 1 0W-40, and I got excellent results after 4 track days spanning 1500 miles. I honestly don't think Mobil1 is a bad oil at all.

On another note, I don't think you should judge oils on just zinc levels, etc. Check out how your engine fares as you attend track days. After all, the lab analysis will provide the information (like aluminum count) to show if you're OK or not.

Kamran

I'm curious, how many miles did you have on the engine, and how many times the oil was changed before this test? It seems your phos zinc levels didn't drop off much from specs.

Phos and zinc actually are the addetives in synthetic oil that protect valve-train and scuffing. Just look at the Mobile 1 Race oil phos zinc contents. Of course too much of it isn't good either.

Oils like Motul 300V which are ester based, are more stable, and have a higher shear stability than synthetics.

However, oils like Motul are not designed for "extended" oil changes.

I'm hoping my next oil test shows some stability in these levels.

There was a time when during 24 hour races competitors were blowing up engines just before the end of 24 hours. Soon enough they realized by increasing phos and zinc they were able to extent engine life to finish the races.

X25

If you're using 5W-30, I think you should switch to 0W-40 for sure; it's a much more appropriate spec for this engine in my opinion. Actually, Euro spec Corvettes come pre-filled with it.

Kamran

I've switched to 15W50. But my base line test was on 5W30. 15W50 has a higher content than 0W40. 0W40 is kind of in between. I'm hoping 15W50 is more stable.

I'm not sure if the European oils are the same as US oils. I understand some countries like Germany still allow the high content higher grade Extended Perf Mobil 1, while not allowed in the US.

How many miles was on your engine and what oil change was the test you posted above?

OBSSSD

Mobil 1 0W-40 is far superior to the domestic 5W-30 spec'd grade. Not sure why anyone would use regular 5W-30 in their Vette, except "GM says so" LOL...

X25

It was fun 500 to 2000 miles, so duration was 1500 miles and 4 track days. This is all written on the oil report, too : )

Indeed, 0W-40 is sold as "European formula" here, so I'd think they're hopefully the same formulation.

Kamran

Thanks. I saw that in the report, but since it was such a round number, I wasn't sure if it was the actual.

Well, 0W40 certainly seems to be way more stable than 5W30. Now at least I can draw my own conclusions on M1 5W30 for future ref...! So much for that.

goec2468

I don't know what oil is in the engine from the factory in the European Corvettes (in Europe you get the Z51 only, not the base version), but since it is changed after 500 miles anyway, it is not that important.
The dealers all fill 5W30 dexos oils, my dealers uses Fuchs oils.
Since I put Motul in almost anything I drive, I had the dealer to fill this one at the last oil change: http://www.motul.com/nl/en/products/...ic-dexos2-5w30

The oil works very well, also when driving 130mph for hours on an German highway and occasionally 180 mph.

When out of warranty, I will use Motul 300V, I just don't know yet if I will use 5W30 or 0W40.

Regards

Götz

X25

You know, we're supposed to change our oil around 500 miles, and this was the change right after that at about 2000 miles. Since I believe it's not important, I did not dwell on exact mileage numbers, but it should be very close : )

You'll start wondering if I have different motivation, but I have to say that I got good results with 5W-30, too, back when I got it tested for my '14 Camaro SS 1LE. The theme there was that despite hitting high oil temps (as much as 290 degrees F IIRC), the oil was in good shape. I'll find that report, too.

X25

Found it. It was to test the affects of high temp, but wanted to share anyway:
http://www.camaro5.com/forums/showpo...&postcount=368

Kamran

I've used both of those Motul weights on my FRS, and liked 0W40 slightly better. I think for the Corvette, if you are going dual duty, 0W40 is the ticket. As also is the case with X25's test results.

I had used 0W40 before with my FRS. I think 0W40 is certainly a better weight than 5W30.
I'm starting to wonder if dealer in fact did put in Mobil 1 5W30 as I specifically asked them for it? Or was it something out of their barrel? I changed it at 465 miles and put 1200 miles on it and my phos zinc levels were at 620 and 693 respectively...? Much lower than yours!

goec2468

That is a concern I also always had and that is why I bring my own oil.
Usually you have to pay a "fee for the old oil", but I don't mind.
I am not bringing the oil to save money (nothing wrong with that), but to make sure it is the oil I want in the engine.

Regards

Götz