RP or mobil1 don't go well with our motors. I would use Brad Penn/Rotella/Valvoline VR1 along those lines.
There's nothing wrong with using Mobil1 or Royal Purple as long as you understand the ratings and what they mean. Mobil1 is decent but succumbs to contaminants and dilution more quickly than some other oils. It's SM rated, so technically it's acceptable for the subaru. I'd consider a 5w40 for that one. In fact, for the money they're charging these days, I'd just skip it altogether. It's not a bad oil, it's just that there are tons better out there. The whole 5w30 recommendation is a laugh, IMO. A turbocharged engine that's modified should not run piss water for a lubricant, especially knowing most of the assholes complaining about Mobil1 are the same assholes who don't wait until the oil (not the coolant) is up to full temperature before jamming the throttle open.
Royal Purple is an outstanding oil, just like Amsoil. The trouble is, it's not SM rated. According to Subaru, using an oil like that is sacrilege. In their quest for protection and lubricity, the kind folks at Royal Purple gave the SM standards the middle finger. They didn't believe it was worth it to remove significant amounts of pressure-protecting additives, just so the catalytic converters and O2 sensors could live a little longer and keep warranty claims minimized. Amsoil found a way and earned an SM rating on their oil. Different makers, different philosophies. That's really the gist of it all. If you use a non-SM rated top tier synthetic in your engine, it's not going to blow up. In fact, it *may* even physically protect a little better due to the additives that are less present in SM "energy conserving" oils.
I've been running non-SM oils in my Jeep and haven't thought twice about it until a recent experiment. 140k and it's the quietest 4.0L you'll ever hear - NO valvetrain noise at all. The exhaust is louder than the mechanical noise of the engine. For kicks, I switched over to 5w40 Rotella T6 full synthetic (an SM-rated diesel oil) and the valvetrain noise grew significantly louder within 5 minutes of changing the oil. A few hundred miles later, I had to remove the valvecover and tighten rocker arms. I'll be switching back to Amsoil after this interval is up and that's an SM rated oil. Same story with my Ninja 250r. The most popular oil in the Ninja owner's group is that 5w40 Rotella T6 and I can't understand why. Must be a cost-related thing. After putting that in, my clutch basket sounded like a midget was banging away with a small metal hammer. My valves, which were silent as could be, suddenly need serious adjustment within 200 miles of that oil change - they're very loud. I made no other changes to the engine. Now you tell me what that means. Once again, switching back to the recommended 10w40 Amsoil SJ-rated motorcycle oil and clutch engagement is much nicer, clutch basket is quiet as can be. Valve still need serious adjustment though. Same with the jeep. They're clacking away again and within a 500 miles of re-torquing the rocker arm bolts. Lesson learned.
Topic: question tht i cant find on the internet! (Read 1094 times)