I've used royal purple for the past 3 years, but it was free so I might be slightly bias.

 

Damn. Any free synthetic is good synthetic, to me!

 

Royal purple shears quite a bit and they were sued last year for false advertising by British Petroleum. Royal Purple is not even in the same league as Redline. Royal purple is a group III/IV while Redline is a true Polyol Ester synthetic with a good dose of zddp. I have used 10w-40 Redline in my camaro for years and used their atf exclusively going on 17 years. Everything always looks shiny and new inside. When you get to this level, there is a difference in oil. If you just buy from wally world, then the performance margin is minimal. Redline 5w-30 is a heavier 30wt and woould be one of the best choices for your LS1.

 

That may be true with the RP you can buy in the store, but saying all RP sucks because of this one line is like saying all GM sucks because the Pontiac Aztec sucked.

The RP XPR oils you have to order online because they don't meet emission reqs are very very good oils.

 

That is a very poor comparison sorry.... The XPR oils shear when tested via UOA. It's a well documented subject.And they were sued for misleading consumers!!! I don't go around bashing an oil or product for that matter that I don't have proof on. There are much better race oils out there. There is a reason nobody uses Royal Purple in the big leagues. The same goes for lucas. They paint the logo on the car and dump in Redline,Motul,amsoil,mobil 1 and go racing.

The emissions issue does not affect the oil being sold in stores. There are many high zddp oils on the shelves of several autoparts stores. Redline and amsoil being two of them. It just so happens a good chunk of their business is mail order.

 

I would like to see the UOA from say, XPR 10w40. That's what I ran before this year. Not being confrontational, I just want to read them/it.