Yeah. Ok, now that that's out of the way, here's a few of my personal opinions, which I do not hold to be any better than anyone else's.
- After break-in, I whole-heartedly believe in synthetic, which for my mustang is a must. Synthetics require less additives for the grade requirements. They are absolutely less prone to thermal breakdown and have higher shear stability.
- I think anything in the 30-50 weight range is acceptable, but I like to go right down the middle with 40.
- There is definitely something to ZDDP (zinc di-hamminahammina
Phosphate) It's supposed to protect better when metal to metal contact is made. It's been reduced/eliminated from modern oils to save catalytic convertors, which I don't have. They say this additive is particularly suited for flat-tappet cams. So a higher zinc content is a positive in my mind. You can get this stuff as an additive and do not need to research oils to find out which has it and which doesn't
- I have a water cooled turbo, and I give the car at least a minute after driving to allow the turbo to cool. So I believe I have less oil coking to worry about. Therefore, I'm not as worried about detergents and additives often found in the diesel oils. Diesels are not driven the same way performance gas engines are. I think they make oils more susceptible to thermal break down and shearing. Similarly, I am not a fan of "race" oils, because these oils are usually designed with the idea in mind that they will be changed very often. So, they have little or no detergents, and they will allow sludge build up/coking if run for long periods of time. Manufacturers often advise against running their "race" oils on the street, and there's a reason for that.
- Many oil tests/comparisons you can find online seem bought and paid for by particular companies, because their oil wins in every event, or in the only event tested. You'll notice that one set of test results bears nothing in common with another tests. Without a consensus, I don't trust any of 'em.
- Lastly, with my expensive engine I change my oil too often... about every 3k miles. With synthetics, this is absolutely not required. I'm considering using the oil drained from the mustang in my other cars to get the full life out of the oil while still keeping clean, fresh oil in the too expensive engine. Some people say you can run a synthetic oil for 15k miles without risk if you change the filters frequently. I don't buy it, but it could be true.
- I consider valvoline, amsoil, and mobil 1 oils to be premium brands, and I trust their synthetic products. I do not believe all of the hype concerning Royal Purple, Rotella, or the other oils you'll often hear internet car enthusiasts repeating with zeal. I don't have anything against them, and I doubt there's anything wrong with them, though. I just never see real documented independent scientific test results that I trust when I hear people gushing with compliments about them.