Very impressive chart, looks like you do it yourself? I'd like to see it go even further like to -20f. I like 0w30 because it offers the good cst at operating temp, plus many guys on the board have it kill their piston slap, experiences of the board is huge, nobody has complained yet about 0w30.
But as I've been saying for a year now since piston slap came up, don't be afraid of 0w20 ram forum. Hammers post explains why. You see why 0w30 or any 0 winter rating oil only buys you -5 degrees in operating viscosity, because they are close to their cousin 5w30 or 10w30 in cold performance. In other words weight is the biggest factor in cold performance, 5w20 is better then 0w30 or 0w40 in cold performance.
If you look at a standard visc chart it looks confusing, why? Because the factor the viscosity charts omit is that the application calls for a certain weight oil to begin with, so when they say 0w20, 0w30, and 0w40 all have the same low operating performance the chart itself takes into account the application that may call for a thicker oil.
Hammers chart is clearly in conflict with this chart without that key fact, hammers chart is 1,000 correct for oil weight, this chart is 1,000 correct when you add in the consideration of the application itself. Which is another reason to consider hammers chart more if you are having a real hard time with cold performance and that 0 rated oil. Hammers chart spells out why, 0 winter rated oil will only buy you so much performance, but going down in weight buys you a lot more.
Also, if you have hemi tick plus cold piston slap like corey, justin, kyle and others. Then you have to pick your battle, in viscosity terms what is good for one isn't good for the other. High cSt good for tick, bad for piston slap. The good news is that it isn't always just about viscosity, if that was true then lubegard wouldn't be killing those hemi ticks that it kills. So same thing we have been doing, use high additive with beneficial ep additives and the oil the balances both piston slap and tick. However, if you have to fix one, warm idle tick is what I would worry about most, cold piston slap sounds bad but isn't nearly as dangerous as warm idle tick that eats those cams.
The other option is a sump heater, maybe the best option. A sump heater can make a 40 or 50 weight oil have better cold performance then a 0w20. I know guys like Corey and Kyle have also at least went to engine block heating. Which is another weigh to avoid cold piston slap, as the cold itself is what is to blame for cold piston slap. Two more options to avoid cold piston slap, heating the block or heating the sump. Maybe those guys can chime in on how effective that has been? There is a lot more to consider even at 20f, no matter what like hammers chart shows the oil is just thicker at 20f. But, there are many strategies a guy can take, engine heating, sump magnet heater, going down in winter rating, and/or going down in weight.
