Quaker State volatility is outstanding! I'd use any of these oils but throwing in current price and the fact that i don't go past 5k miles...
1. Quaker State, 2. SuperTech, 3. Valvoline.
But if you're all about TBN, Castrol Edge looks stellar.
TBN...Calcium registers as part of the TBN, so with the new formulations with reduced Calcium, it only makes sense for the TBN to dip in virgin samples.
The days of high calcium and no magnesium oils appear gone. And even Valvoline has ditched the sodium to go to magnesium. If you want high Calcium and no magnesium (like Pennzoil and QS used to be), some of the 40 and 50 grades may still give it to you.
I've said it several times on this site that QSUD is the best bang for the buck in synthetic motor oil
And here's proof !!
A 5quart jug at ChinaMart is under $20 bucks everyday without a sale price or rebate.