I have always been interested in which one is really better?

Amsoil or Royal Purple

Never used amsoil.. so I'm kinda 1 sided

I've used Royal Purple in my Suburban and it was great. I'm using Amsoil for my Tranny and would probably use the oil except for one thing. Thankfully we have a Valvoline Express Care shop and I get my oil changes free. So right now I'm using Valvoline's Synthetic Extreme Blue. Seems to work pretty well.

I've used Royal Purple in my race car from a partial product sponsorship, but I changed the oil after each race weekend. I wouldn't use Royal Purple in my daily drivers unless I was practicing an aggressive oil change interval, but that would be cost prohibitive for me.

In my experience, the racing oils give up varying levels of stability, shear and protection to reduce drag/resistence, so the rotating assembly spins easier - I think some of the oil testing results bear that out. Also, Heath may have the actually data or I'm sure can shed more light on the matter. I generally use/used Mobil 1 and Amsoil synthetic lubricants in my daily drivers.

I think all are doing an excellent job. They all have quality products. I have had engine failures through the years, but never one due to oil.

I run Mobil-1 10w30 in the boat (496/8.1 GM/425HP)
I run Mobil Delvac-1 5w40 in the pickup.

There are several other great brands. Just pick one and run with it. The two you already mentioned plus TORCO, Lucas, Redline, Rotella,.......

Let the great oil debate begin,it's like seeing the first robin in the spring here on the board. For the record I use amsoil series 3000 heavy duty diesel oil and have been happy with it .

Neither.... Never was a fan of Amway or the purple stuff.

I been using Amsoil Series 3000 HD Diesel Oil because I saw the specs had the highest wear and TBN additives, of any oil, and lowest ASTM Four Ball Wear Test results. So far it seems okay, but then I never lost an engine to failed oil yet. It does seem to go longer between changes, as verified by analysis - looking at maybe 15,000 mile intervals or more, much more if the first analysis is any indication.

I've never used RP either, just hear what other people have said. Vin63 mentioned the lower shear stability and I think there is something to that. Their gear lubes have been shown to shear out of range anyway, and this does help reduce drag in those racers. And if changed aggressively, they get by doing that.

Neither, sticking to dino oil. Chevron DELO 400LE CJ-4 spec. Doing a fine job and getting 8-10k miles bwtn changes.

I have been using Amsoil products for 29+ years now.
In my 2002 GMC Duramax, I am using the Series 3000 5w-30 with the dual remote filtration. I send in a sample of the oil to be tested once a year. So far, I have 49,000 miles on oil without drainplug being removed. I just change filters and top off oil level. The truck uses NO, ZERO, NADA oil between filter changes and it always looks golden brown. Keep in mind, this LB7 has no EGR, PVC ,Catalytic Converter or DPF. I have never used Royal Purple.

Been using Schaeffer's Supreme 9000.

Delo 400 15W40 CI4+...got myself a fair stash of it before it disappeared...

I have been using Amsoil products for 29+ years now.
In my 2002 GMC Duramax, I am using the Series 3000 5w-30 with the dual remote filtration. I send in a sample of the oil to be tested once a year. So far, I have 49,000 miles on oil without drainplug being removed. I just change filters and top off oil level. The truck uses NO, ZERO, NADA oil between filter changes and it always looks golden brown. Keep in mind, this LB7 has no EGR, PVC ,Catalytic Converter or DPF. I have never used Royal Purple.

Sorry to say but if your oil is still golden brown after 49,000 miles it isn't doing it's job very well.

As far as synthetics verses dino and considering the quality of modern day lubes the only thing synthetic MO does better than dino is protect better at temps we never see anyway. Another difference would be a lighter wallet after an oil change. Without a 2nd thought I would put my dino UOA results up against any synthetic.

Awhile back, Heath provided some test results about Royal Purple GEAR oil, which showed excessive shearing; but I have not seen tests of the MOTOR oil. These two types of lubricants are obviously quite different in application and chemistry, so I'd like to see some actual test data on the MOTOR oil.

I have been using the RP 15w-40 and the oil analysis was good. My fuel economy went up about 3 mpg when I switched to RP from Dino oil. I use the Amsoil EAO 52 filter, which seems to be well regarded.

After this cycle of RP, I will likely change to the Mobil synthetic as it seems well regarded by all, and continue using the EAO 52 Amsoil filter. I installed the Fumoto drain valve last change, so expect oil changes to be much less trouble.

amsoil is overpriced in my view, but owell. anyway, i use rotella 15/40 in motor, amsoil torquedrive in trans, valvolene 5/30 synthetic in tcase, and amsoil in diff's

Between the two, Amsoil. You should look at Schaeffer 9000 also, then go with what you are comfortable with. I'm a Schaeffer guy.

Dane

Another vote for Schaeffer 9000. Not in the poll, but it is what I use.:cool:

Royal Purple and Red Line underwhelm me.