Maybe I missed this somewhere but I will ask anyway. GM recommends a 15w-50 oil for "racing" and "performance" driving. I can't find a 15w-50 dexos approved oil. Anyone? Mobile 1 15w-50 is not Dexos approved.
Manufacturers haven't used "break in" oil for decades aside from a few cases where Honda added additional moly to some specific engines back in the late 90's so no, there is no special break in oil in any C7.As 5w-30 Mobil 1 is factory fill for the z-51, can we conclude that there is no special "break in" oil used? And second, as Mobil 1 is factory fill for the z-51, can we assume the initial free oil changes at the dealer will also be Mobil 1 ???
Old people use old phrases........ Most simply consider the oil used during the engine break in as "break in oil", not that it is any different than the oil that will replace it but that it has particulates in it that come from the break in process.I know that there is no such thing as break in oil these days, but I keep on seeing references to people wanting to get the 'break in oil" out of their engines before the first GM recommended oil change. Do they know?
Honda still uses a specifically formulated break-in oil, and in my experience it's very effective (I'm the original owner or a 2005 Civic that just passed-through 475,000 miles).I know that there is no such thing as break in oil these days...
Hmm, i wasn't aware they were still doing this. They would be the last I believe, it's not a standard practice, certainly not by GM.Honda still uses a specifically formulated break-in oil, and in my experience it's very effective (I'm the original owner or a 2005 Civic that just passed-through 475,000 miles).
"Your Honda engine was delivered with an oil that is specially formulated for new engines that have not yet developed their "natural" wear patterns and may contain minute particles from the manufacturing process.
American Honda strongly recommends this special oil be left in the engine long enough for these wear patterns to develop, usually until the first maintenance interval specified in your Owner's Manual, based on your specific driving conditions." Frequently Asked Questions | FAQ | Honda Owners Site
It's not silly from either a marketing or an engineering standpoint. The DEXOS spec oil provides the combination of protection, efficiency and driveability the engine is designed for. The higher viscosity "racing" oil provides an added level of protection the motor needs under the higher stress use. To provide that higher level of protection it gives up varying degrees of protection, efficiency and driveability under "normal" street driving conditions.SO BACK TO SUBJECT....GM on one hand tells you to use dexos approved oil and then says but if racing or performance driving recommends a 15w-50 oil which is not a dexos approved oil. Just seems silly to me to make a big deal about the "Dexos" approved but then turn right around and recommend a non dexos approved oil. I guess the viscosity any 15w-50 oil is such that it is safe regardless of dexos? Why not run 15w-50 all the time if it's so good it doesn't need dexos approval? Thanks in advance for your answers to my question.
Not to be mean but yes, you are wrong. Ambient air temperature is irrelevant as long as the engine can manage it's internal heat. It's the stress of high performance driving and / or racing that raises the internal temperature of the engine and oil, not ambient air temp.I believe if you live in A hot weather area then I believe that A 50W oil would be good for the cylinders and rings.I do believe that A low weight oil in hot weather isn't good for the engine.I've always believed this.Am I wrong?
Too thin of a oil and in hot weather, engine and track use becomes blowby, through PCV and into the intake where reverb of exhaust can send the oil fumes to aircleaner.I believe if you live in A hot weather area then I believe that A 50W oil would be good for the cylinders and rings.I do believe that A low weight oil in hot weather isn't good for the engine.I've always believed this.Am I wrong?
That's all well and good but he never mentioned track use.Too thin of a oil and in hot weather, engine and track use becomes blowby, through PCV and into the intake where reverb of exhaust can send the oil fumes to aircleaner.
Thin oil flows quicker so it cools down better and gets a bit better MPG
Thicker weight flows slower so it retains more heat, though it reduces blowby and of course bit less MPG
For racing I have always mixed 5W30 and 15W50 Synthetic 50/50 ratio to get like a 10W40 and at races where powertrain is maintained at high RPM, MPH and engine loads like Open Road Racing the thicker oil does a much better job, less oil and blowby issues
That's all well and good but he never mentioned track use.
Under normal driving conditions the cooling systems maintain the internal temperatures with a certain range regardless the ambient air temp so what you do racing has no bearing on street use.
Oh, and mixing engineered oils to get a target viscosity ratio simply doesn't work the way you describe and in some cases the blend of incompatible additive packages can cause far more harm than good.
You didn't mention you were blending the same base stock, that does make a difference.Mobil 1 engineering for GM racing themselves told me of the mixing and it does work and the lack of oil use and blowby shows it and not saying to mix brands but same Synthetic Mobil I
If a Corvette is driven on the street as it was designed ( bouncing rev limter, 100% engine loads. etc) for, the thicker grade works as well as if track use.
Under "normal" street driving if means sticking around 2,000 RPMs is one thing but higher loads, higher oil pressure, more flow, more oil cooling and not about outside temp but overall engine/bay temps.