[quote author=MKZman link=topic=89847.msg2152660#msg2152660 date=1205588014]
Why did you switch from Synpower to Amsoil?
If I read this analysis, the MC has more Barium and Boron and a higher viscosity. Were these both 5W-20 oils?
People need to realize that oils and engines have changed a lot. I suspect as oil prices increase we will follow Europe with even longer OCI's.
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I got the Synpower on sale and it was a 5W-30. I switched to Amsoil because of their great products and the I wanted to back to the 5W-20. The MC was a 5W-20 but the Synpower was the 5W-30...hence the difference in viscosity...Synpower is the one on the left. The TBN of the Synpower was virtually the same as the MC despite the fact that it was run over 1000 miles more. This is what synthetics will do for you.
Engines and oils have changed TREMENDOUSLY. I try to tell people that. I work at an auto parts store part-time as a manager and I try to impart this info to customers, but people want to use "what I've been using for 30 years". It's as if they think technology hasn't changed and the product they used 20 years ago is much better. You try to give them facts but they go off of "my friend used so and so oil and he had sludge" stories...never mind there could be a million other things that caused that sludge, like fuel dilution, etc.
Engine clearances are much tighter nowadays, that is one of the reasons you see the thinner viscosities being spec'd by manufacturers. Today's SM rated oils are awesome and can go much farther than the old 3000 mile standby which everyone seems to still fall for...that's where that TBN comes in. That Synpower was at 3.7 TBN. A TBN of 1.0 means the oil life has been depleted and it should be changed. I could have taken that oil out another 2000 miles, at least. Today's conventional oils can go 5,000 miles...plenty of people take The Yellow Bottle out to 5 and even 7,500 with great results...you can see these analysis at bobistheoilguy.com. Again though, most don't like facts...they like to speculate and repeat old stories some old wrench turner repeated to them 20 years ago.