I just got RPin my store and the best we have is 15w40, will that be to detrimental from the 20w50 I have been using?

 

You're fine using as low as 10w30 if your engine is under middle age in terms of mileage or if you premix.

Be careful of Royal Purple though. While the stuff is fantastic in other cars, the intense rotor temperature followed immediately by the oil cooler tends to turn RP into water in a couple thousand miles or so. That's better than Amsoil though, that junk will go from 5w20 to 50wt in 3 or 4. Not to mention the base number goes on vacation and never writes back.

Redline seems to hold up the best in my own experience, and Mobil1 does pretty well too.

 

You've had bad experience with Amsoil? I've used alot and thought it held up better than Mobil 1. I seemed to have gotten about a thousand miles more with it, before it started getting dark. I have a TO4E 60-1 turbo, and a really good street port.

 

im usung 5-30 rp on my fresh bridgeport. it was th first oil change since i got it. so i have 1k miles on the motor.Im guessing that im using the right stuff. it seems to rev easier.Should i premix?

 

Yeah. Ran that for a few months in my 2.8 Fiero and sent it off to Blackstone Labs after 8000 miles ( drive about 700-800 hard "city" miles per week, so it goes quickly). The color was still good, but it came back as 20w50 and had a base number of about 0.6 (anything under 1 is considered "dead" oil), which meant my engine was eating itself from its own acid production. I've seen similar numbers in Camero tests, so I don't consider it a fluke. I go through oil over twice as fast in the 7, probably from the heat differential, so I was making a rough extrapolation since I'd never let the stuff near my car.

RP held up great in my other cars, but Mizenki, my 7, just shreds it to where it has to be replaced frequently enough to not be cost-effective. Granted I drive very unneccessarily--to almost an AutoX degree when just going A to B to C all night--and a mild driver might not experience that kind of breakdown, but I feel it's important to make the point because the danger exists.

 

If everything was turned and blueprinted during the rebuild to really make it a 0-mile motor, you shouldn't be using Royal Purple yet. Any synth oil that uses molybdenum disulfide needs a break-in period of at least 2000 miles on regular oil. Otherwise the moly platelets will set wrong on the rough friction surfaces and cause an assortment of minor problems from hot spots to uneven wear. Nothing major to my knowledge, but it's still something to avoid.

 

Yeah completly freash motor. only thing reused was the waterpump.

 

Well, I've got nothing to add then. I don't really have a recommendation for you at this point since you're already well into the break-in period. It's not like you just took 20k out of its life or anything, just change your oil filter at 2000 to be on the safe side.