Quote
Being supercharged find the lowest noack/highest hths rating synthetic
Wise words. In practical terms, that's M1 10w-30 HM. HTHS 3.5. (keep in mind HTHS is a logarithmic scale, so don't think "oh, 3.2" is good enough"). If you aren't starting it routinely below 10F (e.g., you have a 2nd car for nasty weather), then run it year round, even in MT. Let me quote Molakule from a long time ago (over 15 years!):
Quote
A jump in HTHS by about +1.5 results in approximately 1/5 the wear. Now this relationship is not linear and flattens as one nears a 40+ weight oil.
*
We are not talking about a 1/10 difference between 3.2 and 3.5 like appears, but rather a 25 fold difference (1/5th of 1/5th). So I'm always going with a 3.5 HTHS where it meets my climate needs vs. a 5w-30 with a 3.2 or lower HTHS. Heck, even mediocre 10w30's have an HTHS of 3.2. So look beyond the mere viscosity rating. Serious oil gurus here (like Shannow), have argued that oil marketed by viscosity is outmoded and it would be better to discard that and label it by HTHS.
Quote
My job is seasonal for nice weather only so I don't do much or go places in the cold months.
So I don't exactly know what this means, but if you don't HAVE to start it when it has set outside overnight in 10F or lower, just run the 10w-30 year round and there is no harm and only good.
* Here is the 2003 post I am quoting:
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/530501/1/HTHS