Please note that these are my observations only and only that, my opinion.
Mobile 5w-30 vs 15w-50.
Location: Southwest Florida .. cold weather..never heard of the thing.
The following was conducted over the course of a 1 1/2 months and 4 oil changes in even intervals.
oil changes.
1st: 5w-30 max pressure 25psi when hot.. notice some loss in acceleration, I thought it was everything else but my oil.. no cel..nothing..cleaned filter..etc.. process of elimanation was to go to what I did change.. oil.
2nd: 15w-50.. I definately notice my power come back..max oil pressure when hot 45-50psi, but through out the possiblity of the oil because of what a lot of people on this site have said, so I convinced myself it wasn't the oil.. even though again it was the only thing I changed.
3rd: 5w-30.. back to max 25psi and back to the decrease in acceleration.. now I start to really wonder and believe it IS the oil weight.
4th: changed it back today to 15-50 and even my girlfriend notices a "sudden" to her anyways increase in power. Torque at midrange is definately increase and oil psi in back to 40-50 area when hot.
00 svt engine has 70,000 miles on it.
I also understand the haynes manual said normal oil pressure to be 20-45psi at 1700 rpms..1700 or 1500 not sure.
