Couple questions: AMSOIL vs Royal Purple

RANDYZ · Dec 9, 2003

I was at the local NAPA checking out the NAPA gold filters that a lot of folks on the board seem to like when I noticed they stock AMSOIL & RP. Both oils were the same price so I was wondering which would be the better choice?

They had two different kinds of AMSOIL, one said change at 7500 miles, the other said 25,000. They were both $5.33 qt which seemed odd as one must be better to go the extra miles. How much is a qt of AMSOIL from the online dealers?

Thanks, Randy

Jason8691 · Dec 10, 2003

The 7500 mile AMSOIL is API approved, the 25K is not. I dont know online prices, but AMSOIL would be your best choice even if you had to pay a little more for it.

medic · Dec 10, 2003

I'm not sure about the Royal Purple, but that is a good retail price for the 24,000 mile Amsoil. Don't buy the stuff label for 7500 miles unless you NEED an API certified oil.

You should be able to save a bit of money by going through one of the dealers here, but remember, by getting the oil through one of the "BITOG" Amsoil dealers - you'll get excellent customer service, knoweldgable Q&A, a dealer that will work with you every step of the way, and be putting money back into this site. How much of this can you get at NAPA?

sbc350gearhead · Dec 10, 2003

A local Napa sells RP for 4.69 a quart. No store that I am aware of in this area sells amsoil. I have used RP with good results, but I have never used amsoil, so I really can't comment on it. Both seem to work well in certain engines. Amsoil seems to be more consistant and does not seem to have the shearing that RP does. There are many many more UOA's posted on amsoil than RP so the numbers might be skewed a little in comparison. Terry claims that RP is a good solid oil. You will probably experience more of a HP and fuel economy gain with the RP.

MRC01 · Dec 10, 2003

quote:

Originally posted by RANDYZ:
I was at the local NAPA checking out the NAPA gold filters that a lot of folks on the board seem to like when I noticed they stock AMSOIL & RP. Both oils were the same price so I was wondering which would be the better choice?

IME they're both decent oils. RP is "OK" but its UOA results are generally not as good as Amsoil (or as good as Mobil 1). Since they're all about the same price, I'd use Amsoil or Mobil 1 over RP.

buster · Dec 10, 2003

I agree with MRCO1. Amsoil/M1 have two of the most consistant oils on here IMO.

TR3-2001SE · Dec 10, 2003

And I agree with Buster!

K-Man · Dec 10, 2003

Keep in mind that Royal Purple street oils are semisynthetics, not full synthetics. Only their racing oils are full synthetics. With that in mind, $5.33 seems high. I've seen Royal Purple street oils sold for a bit less than that.

My opinion: of the two, go with AMSOIL.

RANDYZ · Dec 10, 2003

Thanks for all the replies.
I have been using Mobil 1 in both my vehicles but seems like there are more and more post in favor of AMSOIL. I think I will place and order with a site sponser for some as I also want some gear lube for my 2003 Dodge Ram 1500.

Ken4 · Dec 10, 2003

I am more impressed with the RP UOAs than the majority of the Amsoil UOAs.

Patman · Dec 10, 2003

quote:

Originally posted by Ken4:
I am more impressed with the RP UOAs than the majority of the Amsoil UOAs.

I'm surprised you would say this considering we've only seen maybe 2 or 3 really good RP reports, one of which is from a WRX (which is always easy on the oil) while we've seen quite a few really good Amsoil reports. Amsoil is one of the most consistent oils out there.

Ken4 · Dec 10, 2003

I seem to be seeing more 'consistent' double digit wear and only rarely seeing single digit wear.

Sin City · Dec 10, 2003

RANDYZ, I think you made a great choice.

Patman · Dec 10, 2003

quote:

Originally posted by Ken4:
I seem to be seeing more 'consistent' double digit wear and only rarely seeing single digit wear.

But that's because most Amsoil users go longer on their intervals, so if you factor out their wear in terms of ppm/1000 miles, you'll see their wear numbers are very good.

You don't see many RP UOAs on here where people have gone over 5000 miles, but we've seen lots of Amsoil reports with much more miles than this. You have to take the extra mileage into account, not just the raw numbers.

mikep · Dec 10, 2003

Between RP and Amsoil, Amsoil would get the nod from me. Like others have said, UOA reports here with RP have been less than stellar.

As for the reps here at BITOG, they are extremely knowledgeable and accessible and would certainly get my biz if I were to buy Amsoil again.

Mikep

Ken4 · Dec 11, 2003

quote:

Originally posted by Patman:
But that's because most Amsoil users go longer on their intervals, so if you factor out their wear in terms of ppm/1000 miles, you'll see their wear numbers are very good.

You don't see many RP UOAs on here where people have gone over 5000 miles, but we've seen lots of Amsoil reports with much more miles than this. You have to take the extra mileage into account, not just the raw numbers.

One thing I find missing in most UOAs is 'Time Duration on Oil'. A car taking 2 months to complete 5000 miles will have very different results from the same car taking 6 months to complete the same amount of miles. The theory of ppm/1000 miles is also not an ideal way of looking at it. 3MP oil study shows exactly that. Wear/mile improves the longer you use the oil. But if everyone started doing 1000mile UOAs, the results would look terrible if you used a ppm/1000 mile projection.

Patman · Dec 11, 2003

I always put the duration (in time) of all of my UOAs. I agree it's very important.

TooSlick · Dec 11, 2003

Ken4,

You weren't a math major in school, were you?

Seriously though, the reason the apparent wear rates are dropping in the 3MP study has to do with the amount of makeup oil he is adding in this extended drain study, as well as the amount of metal that can actually be suspended in the oil, rather than settling out in the oil pan. He didn't start adding makeup oil until the oil had been in service for about 3000 miles, and you always have residual wear metals remaining in the engine after an oil change. As a result, his first three data points are "skewed' higher than they should be relative to the X axis. The fourth data point is skewed lower than it should be, since 0.5 quarts of oil was added. When the filter was changed @ 15k miles and 1.5 qts of makeup oil were added, it dropped the wear metal concentrations for the last three points way down towards the X axis, so the curves look like they are necking over.

Don't feel bad about not catching this - I sit in endless meetings five days a week and look at Powerpoint charts with charts and graphs on them, and I've been doing it for over twenty years. Ah, the glamorous life of a rocket scientist ...

Tooslick

Bror Jace · Dec 11, 2003

I have to agree with Patman and others. I was anti-Amsoil when I came to this board but the UOAs have show it to be very stable and suitable for (somewhat) extended drains.

I'd take it over Mobil 1 ... and I'd take both over RP.

--- Bror Jace

Couple questions: AMSOIL vs Royal Purple

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