BruceH
BBB Big Bore Boss 322
Still waiting on your answer as to why Ford specs both 5w20 and 5w50 for the Coyote engine
Same engine, same internals, nothing special, other than a different suspension package and an oil cooler.
Now the roadrunner variant of the coyote 5.0 calls for 5w50.
Your one answer was intended use, well if I intend to beat the snot out of my non track pack 5.0 that has the same engine as the track pack 5.0, then I guess using 5w30, 5w40 or 5w50 would be perfectly fine then.
What people don't understand is, not every oil is created equally. I've seen the tests on motorcraft 5w50. After just a few miles it breaks down and becomes a heavy 5w40, so why not just run a good grade 10w40? Hmm, that's what all of the GT500 guys do.
When adding cooler fuels like E85 or running cooler thermostats, you see plenty of gt500 guys switching to 10w30.
Ford's #1 concern is gas mileage. If they do not meet a standard they will be subject to heavy fines. 5w20 oil helps with this on the performance vehicles. Heck it helps on a lot of vehicles, but motorcraft 5w20 does not hold up well to sustained abuse. Paying out a few engine warranty replacements for rattles, slaps and knocks is a lot cheaper than government fines.
Most analysis I've seen on Motorcraft 5w20 shows that it is actually on the heavier side and closer to 5w30, so no harm in running a 5w30 especially if you are introducing more than the average amount of heat into the motor.
As far as people jumping and saying "well, that's what Ford spec'd for the engine" have obviously not worked in any type of product development/engineering life cycle.
The Engineer designs the specifications, Accounting runs it through purchasing to see what the units can be acquired for, if it does not fit a certain pricing model, it is rejected and the specification has to be loosened.
Don't kid yourselves, Ford did not contract Conoco to formulate Motorcraft 5w20 oils because they were top notch quality, they did it because they met their pricing model of Cost vs. Quality vs. Speed of Product Delivery.
If people wanted to follow the above logic "because the Ford said so", then I guess those stock mufflers are really the best... the stock suspension is the best for the car... the stock tires are also the best. No need for a supercharger, the factory Ford induction system is the best, also those headers... nah, the factory Ford stuff is the best.
Like I said in the previous post, all I can do is guess and my guess would be that an all out track car would have different requirements than a dd. I'd further guess they kept the 5w requirement for cold motor starting and warm up. That's the best answer I'll be able to give you. I'm not a motor engineer nor am I a pro race motor builder. I'm just a guy with a HS education who was an electronics tech in the 1980's Air Force who has been building airplanes for the last 24+ years. I would say I don't have the education or qualifications to challange a team of engineers. I do understand basic flow theories.
I'll preface this statement by saying I hate it when people put words in my mouth. Based on that let me know if I have any of the statements concerning your thoughts on this wrong, I'm just trying to point out differences in thinking.
I think the main difference here is I trust Ford engineering and you see a conspiricy with a wide range of players. I see the longevity of the factory cars as proof of the engineering while you still see a conspiricy. I only put faith in api specs while you put faith in independant labs. I just don't buy into the cafe/government conspiricy. Any comparisons to other aspects of the car don't really apply. We are discussing motor oil here. In the end cars running 5w-20 aren't failing. In fact some people are switching to 0w oils for even more cold motor protection. My 2010 Honda Accord owners manual says that's an acceptable oil weight to use with the 3.5 v6.
I know that my modern day vehicles are made so much better than the cars I drove in the 70's. 10w-30 was the standard back then with all the loose machining. I think I'd be starving the motor, especially at start up. Once it was warmed up it shouldn't make much difference.
I still think that more wear would equal less mpg because of more friction. If that's true there is no way the cafe conspiricy holds up.
