GC and M!
- Thread starter mchang204
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Since this is a GC thread, I'll paste my test results that I posted in the past on 2 separate occasions. As a result, the flow of this info might not be too good, but oh well. This does not tell you curoius people if Green GC is equal to Gold GC because this kind of testing can't plus I've never tested Green GC. But it does say good things about Gold GC. Ok, begin pasting:
I did some high temperature tests of Gold GC vs. Mobil 1 Extended Performance 10w30. Measured volume of each oil was added to metal cups and then heated.
In terms of oxidation resistance and volatility, from best to worst, they are
1) Castrol 10W-40 = Gold German Castrol 0W-30
2) Mobil 1 10w30 Extended Performance
3) Mobil 1 5w30
Four oils were tested but both Castrol oils were so similar they both get 1st place. But all of these oils performed very well...not a big difference in rankings except between the 2 Mobil 1 oils. The Mobil 1 10w30 had same volatility as the Castrol oils but appeared to oxidize more from the heat, so that is why it was ranked lower.
Test procedure: Put measured volume of each oil into metal cups and heated them using an iron (have also used a toaster oven, blow torch, and even a strong lightbulb in other tests). Oils were at 375 F for 6 hrs and then evaluated. The % volume lost for top 3 oils was 13.3% while Mobil 1 5w30 was 16.6%. They were in pretty good shape so after that I heated them with blowtorch for 1 minute (temps usually > 600F by end of test). They all darkened and smelled worse after that but none left behind sludge, like Mobil 1 0W-40 and Valvoline 5W-40 have done in past. Bottom line is that the large-spread Castrol 0w30 oil was slightly more robust than Mobil 1 10w30 E.P., which means this Castrol has better basestocks since it's thinner at cold temps and thicker at high temps AND more robust. The more the spread and the lower the first #, the weaker oils usually are, but not so for German Castrol. Also, if extra thickness is desired, you can add some of the now-proven Castrol Syntec 10W-40 to the 0W-30. But this Castrol 0w30 is almost a 40 weight oil at 212F anyway.
Separate pasting:
Valvoline 5W-40 at $4/qt is great bang for the buck but my high temp oil tests showed it to oxidize/sludge much more so than GC. And actually, the Mobil 1 0W-40 behaved exactly the same as Valvoline 5W-40: the metal cups had significant amounts of sludge that could only be removed with sand paper. The temps were very high (400F and above usually); much more than oil sump temps so just because some oils sludged in my tests does not mean they will in our engines. But the tests rank the relative propensity towards it. The Mobil 1 5w30 and Mobil 1 10w30 oils were much more tolerant of high temps than the Mobil 1 0W-40. Amsoil 5W-40 was tested alongside Valvoline 5W-40 and Mobil 1 0W-40 and the former was leagues ahead of the latter 2. Don't know how the Amsoil 5W-40 compares to good 30 weight oils without a side-by-side test, but infer that they'd be similar. The Castrol Syntec 10W-40 and Amsoil 5W-40 are the only 40-weight oils I've tested that are very resistant to high temps.
I did some high temperature tests of Gold GC vs. Mobil 1 Extended Performance 10w30. Measured volume of each oil was added to metal cups and then heated.
In terms of oxidation resistance and volatility, from best to worst, they are
1) Castrol 10W-40 = Gold German Castrol 0W-30
2) Mobil 1 10w30 Extended Performance
3) Mobil 1 5w30
Four oils were tested but both Castrol oils were so similar they both get 1st place. But all of these oils performed very well...not a big difference in rankings except between the 2 Mobil 1 oils. The Mobil 1 10w30 had same volatility as the Castrol oils but appeared to oxidize more from the heat, so that is why it was ranked lower.
Test procedure: Put measured volume of each oil into metal cups and heated them using an iron (have also used a toaster oven, blow torch, and even a strong lightbulb in other tests). Oils were at 375 F for 6 hrs and then evaluated. The % volume lost for top 3 oils was 13.3% while Mobil 1 5w30 was 16.6%. They were in pretty good shape so after that I heated them with blowtorch for 1 minute (temps usually > 600F by end of test). They all darkened and smelled worse after that but none left behind sludge, like Mobil 1 0W-40 and Valvoline 5W-40 have done in past. Bottom line is that the large-spread Castrol 0w30 oil was slightly more robust than Mobil 1 10w30 E.P., which means this Castrol has better basestocks since it's thinner at cold temps and thicker at high temps AND more robust. The more the spread and the lower the first #, the weaker oils usually are, but not so for German Castrol. Also, if extra thickness is desired, you can add some of the now-proven Castrol Syntec 10W-40 to the 0W-30. But this Castrol 0w30 is almost a 40 weight oil at 212F anyway.
Separate pasting:
Valvoline 5W-40 at $4/qt is great bang for the buck but my high temp oil tests showed it to oxidize/sludge much more so than GC. And actually, the Mobil 1 0W-40 behaved exactly the same as Valvoline 5W-40: the metal cups had significant amounts of sludge that could only be removed with sand paper. The temps were very high (400F and above usually); much more than oil sump temps so just because some oils sludged in my tests does not mean they will in our engines. But the tests rank the relative propensity towards it. The Mobil 1 5w30 and Mobil 1 10w30 oils were much more tolerant of high temps than the Mobil 1 0W-40. Amsoil 5W-40 was tested alongside Valvoline 5W-40 and Mobil 1 0W-40 and the former was leagues ahead of the latter 2. Don't know how the Amsoil 5W-40 compares to good 30 weight oils without a side-by-side test, but infer that they'd be similar. The Castrol Syntec 10W-40 and Amsoil 5W-40 are the only 40-weight oils I've tested that are very resistant to high temps.
Hey all I know is that I have swithced from Mobil 1 SuperSyn Xw-30 oils that I had been using before to the green GC (SLX) and like the results very much.
I have not tried the newer gold GC (Longtech II or something like that) or the new SM rated Mobil 1 Extended Performance grades. I don't plan to right away either because with the fair sized stash of the green GC, I don't have to
As far as the "toy" is concerned, it will continue to use either the "witches brew" of SL rated Mobil 1 0w-40 & 15w-50, Amsoil 5w-40, Redline 5w-40 or Mobil 1 T&S 5w-40.
I have not tried the newer gold GC (Longtech II or something like that) or the new SM rated Mobil 1 Extended Performance grades. I don't plan to right away either because with the fair sized stash of the green GC, I don't have to
As far as the "toy" is concerned, it will continue to use either the "witches brew" of SL rated Mobil 1 0w-40 & 15w-50, Amsoil 5w-40, Redline 5w-40 or Mobil 1 T&S 5w-40.
1H-NMR results are the same for both. I should have ran 13C-NMR. We also know from IR that they were the same also. So far it looks like they are the same except for the difference in the additive system. I am trying to figure out the set-up that I need for the GC-MS right now. (without ruining the column).
Thanks for takikng the time to look into this (and, BTW,
Of course, let's assume that the base oils are very similar, or even indistinguishable, this still leaves unanswered the question of why the change in add pack? Obviously, they changed it for some reason. Was it incidental, as in plain SLX is out, and they just filled in one of the new SLX formulae, or did they specifically improve this particular product after further development.
And then, of course, there's the appearance question. I'm not sure I buy the "it's just green dye" theory. If so, why would they have bothered in the first place? We know RP colors its oils purple, basically just to be different. If Castrol were playing this game, why just the 0w30 Syntec, and not all Syntec or the whole line? Instead, at the same time as a known, confirmed add pack change, and possible tinkering with the base oil, the green color disappears. IMO, the green color was inherent in some component of the product that has now been removed. Seems logical, but again, that's just my supposition.
Further insight welcome (needed), of course.
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