I've never known so much about oil until I found this site! Please see this thread: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=005207#000017 I own a 1992 Mitsubishi 3000GT VR4. Mitsubishi 6G72 engine, V6 24V DOHC (twin turbo). The turbos are on their last leg, and are smoking somewhat. I am actually in the process of buying some stock replacements which I hope to have on by this summer to hold her over until I begin to extensively mod her. Anyway after the advice I got in the above thread, I began to use Rotella T 5w40 synthetic. This oil has given me AWSOME results. The engine runs so much smoother, and even sounds smoother. The turbos actually spool a bit faster, and there is less smoking/oil burning compared to what it was before. I have barely driven 300 miles on this oil since I hardly drive the car, however I will get alot more use out of it this Spring/Summer. One day after I took her for a drive I parked the car, turned her off, popped the hood, and opened the oil fill cap on the crankcase. There was hardly any vapor, which tells me this oil can really hold up to high temps. I am very satisfied, and will continue to use HDEO oils in this car, even after I am done rebuilding the motor in a few years. A big thanks goes out to Jelly!