I found this interesting comparison study of synthetc oils. This just confirms my decision to stick with Mobil 1 in my SRT. Mobil 1 Pennzoil Royal Purple Royal Purple Amsoil Weight 0w-40 5w-40 0w-40 5w-40 5w-40 @100F 75.0 74.4 79.9 93.7 82.2 @210F 13.5 13.1 14.3 14.7 13.7 FI Pt F 446 420 465 445 446 VI 185 174 182 179 171 HTLS 3.8 3.68 - - 3.8 TEN 11.8 - 11 11 8 Noack% - 11 - - 8.9 Notes: *The less viscous the fluid, the greater its ease of movement (fluidity). *The lowest temperature at which it can vaporize to form an ignitable mixture in air, the more resistant to being ignited. *Oils with the highest VI will not vary much in viscosity over such a temperature range and therefore will perform well throughout. *Low HTLS will give a better efficiency or MPG. High HTLS gives more durability. *The higher a motor oil’s TEN, the more effective it is in suspending wear-causing contaminants and reducing the corrosive effects of acids over an extended period of time. *A low NOACK rating indicates less likely to vaporize smaller molecules thus making it more volatile.
I've always believed whichever your favorite brand, change your oil religiously with a quality filter you're golden. I switched over to synthetic at the 500 mile mark and it gets changed every 3k. I absolutely hammer my car every time I get behind the wheel. 28K in over 4 years isn't a lot of mileage, but considering it's at full throttle a lot and runs flawlessly lends credibility to proper maintenance. I could probably get away with running a higher viscosity in my car since I have the MDS disabled, but I like the way 5w20 flows.
