So I took a round trip from Ohio to North Carolina over the weekend. This would give me a good test of mileage with GC. On long trips, small variations in driving habits are more likely to get averaged out. Well, I'm happy to report that I set a new record, 33.8 mpg. My previous high was 33.4 with Castrol GTX 5w-30. I rarely exceed 32 with Synpower 5w-40. I do this trip often so the route is pretty similar.
One thing that concerns me though is that gas mileage seems to have jumped up since this trip. Even on a couple local trips today, I set new records for mileage (14 mile highway trips). For example, I have neve gotten over 30 mpg before (even with GC!) from work to home and this evening I got 32.2! I had the same experience with GTX and I attributed it to thinning. But I highly doubt that the GC could have thinned this much given that it has shown to hold viscosity well in UOAs and I only have 1300 miles on the oil. Can anything else cause the mpg to jump like this?
One thing that concerns me though is that gas mileage seems to have jumped up since this trip. Even on a couple local trips today, I set new records for mileage (14 mile highway trips). For example, I have neve gotten over 30 mpg before (even with GC!) from work to home and this evening I got 32.2! I had the same experience with GTX and I attributed it to thinning. But I highly doubt that the GC could have thinned this much given that it has shown to hold viscosity well in UOAs and I only have 1300 miles on the oil. Can anything else cause the mpg to jump like this?