My unprofessional opinion is this: if you drive strictly around town like I do then stick with dino and change it as often as possible due to contamination from idling alot. If I run only on the highway every day of the week then I would make the change to synthetic oil for longevity between changes. Mobil Delvac is 48 bucks for 4 gallons at my local Sams so it don't hurt me too bad if I wanna change my oil at 3k or 5k. The oil tests say that sythetic is still good at x number of miles but to me dirty oil is just that and needs to be changed when it looks good and dirty.

 

I haven't seen any studies and I did some calling around today just to see if any of the companies that do oil analysis have done any and haven't found anything yet... so tuesday i'm going to talk to a couple buddies about the possibility of doing some analysis on the government equipment... so if there are some shops willing to run some fresh motors on different fluids or help come up with an accurate way of testing i'll look into getting the testing done...

I bet in just about every applications you'll get pretty much the same result as long as you change it regularly. its when you go past the recommended intervals that you find what really works

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I do know for a fact that royal purple breaks down extremely fast!

 

That would be a good bet in any apples-to-apples comparison. That's why I qualified my statement to read the "same grade/type category."

The only oil-related internal combustion engine problems anyone ever had was due to operator error involving one of three things: As you said 1) "Change it regularly" 2) Use the correct grade/weight for your application and environment, and 3) Don't let it run too low or too long.

The 1st one and last one are related to the 2nd one, because your application and environment are key factors relating to when you change it or how long you run it. This issue always was really more about asking the right question. That's why it's always been a hot button topic. The question is not "which oil is better/best?" The right question(s) to ask are "Considering my driving style, specific equipment and environment, what would be a good lube maintenance schedule using what type oil?"

 

Synthetic fuels are actually good for the health of the car..originally they were considered as a major factor in the oil leakage from the engine but modern engines have eradicated that issue. Perfectly safe..go for it.

 

If you're planning to change the oil every 3k miles, you can use non synthetic. But if you prefer a longer interval, it is recommended to use synthetic.

 

The best way to know what you oil is doing and how long it lasts is to use Blackstone Labs to test the oil at the oil change interval. Contaminants in the oil tell you about wear of certain engine parts and they can help you to maximize your oil change intervals. I change oil at 7k miles based on findings from this lab and I use Rotella T5.