everything I have read says that they act differently. so if you start with one it is ok but don't switch. They have different configurations. The synthetic hardens seals, the convetional doesn't. If you switch it will cause leaks. If you look back in the posts we had a guy who tests oils for a living and this is what he says.

 

Well as for the guy who tests oils for a living I'd have to say I disagree. And without meeting him I don't beleive he tests oils in the first place. If mixing conventionals with synthetics was such a big deal they would make Synthetic Blends such as Motorcraft which is what Ford uses in ALL of their vehicles. Ofcourse Ford owns Motorcraft so that may be why too....

As for Royal Purple, they guarantee a measurable power difference in any application. I haven't tried it in my engines because it is indeed expensive. However I have used it in my 240sx when I had it and it made a huge difference! The tranny was making an odd crunch when I shifted gears shortly after I bought it. I put some of that stuff in there and it completely stopped after about 15-20 miles of driving with that in it. I also put it in the differential of my 240SX and my Camaro. Can't really tell a difference there but synthetic oil works better than conventional oil at higher temperatures so it certainly can't hurt anything.

Anyway good luck with that.

 

guaranteed hp huh? i might have to bite the bullet and pay extra... i pay for high-mileage oil anyway, so it wouldn't be that much more...

 

LOL, high mileage oil is only like a $1 more than regular. Royal Purple is like $2 more than Mobile 1.

 

true... im just trying to somehow make buying oil that expensive a rational decision... oh who am i kidding i just enjoy spending paychecks as i get them...

 

hah thats how it goes, never streches far enough