Originally Posted By: Skunked
2013 Civic EX, manual
Out: RP 0W-20
In: My last jug of older version Pennzoil Ultra 5W-20. Purolator Syn. 14610 filter.
RP gives me the highest mpg in my experience in the R18 motor (37 mpg in 60% freeway miles). From prior experience, I expect the mpg to drop by at least 1, but I know the protection and longevity of this oil is very good.
Wow, pleasantly surprised with the Penn Ultra, got 1 mpg better over the oci than the RP! So, about a week ago, I changed it out for QSUD 10W30 to see how this thicker oil does. It definitely quiets the motor a bit, but the mpg is lower, currently at 36 after 400 miles.