slipstream444

I've heard a lot of "...I use RP and love it" type of statements in this post with absolutely nothing to quantify the reason for "loving it".

What I 'love' is cold hard facts - not unfounded opinions or emotions when dealing with engineering or mechanical issues - love has nothing to do with it.

Nothing described in the post to which I'm responding even remotely sets RP apart from any other oil - and could have been said with regard to any conventional oil for that matter.

RP is all hype and every third party/independent test I've seen to date demonstrates this.

Here is a relatively recent link (2007) to a gear oil test commissioned by Amsoil (they paid for it). Other than the oxidation filter patch procedure test, all oil performance testing was conducted by an independent laboratory. Physical-property testing (viscosity, viscosity index, pour point and foaming after oxidation) was conducted by Amsoil in their oil lab - the results (and the lab) are ASTM and SAE certified.
The independent lab is one of only a handful of analysis facilities in the U.S. that accomplishes Industry Standardized tests for oil, and regularly does so for nearly every oil manufacturer that sells oil in the U.S.

http://www.amsoil.com/lit/g2457.pdf

This is the most exhaustive series of tests I've found anywhere and it clearly demonstrates - most importantly - the balance of qualities of a lubricant is much more important than any single quality.
You stated you have seen "positive" tests for Royal Purple - if they're actual industry standardized tests (and not some race car driver saying he swears by it... while wearing an RP hat), please post them for fairness and balance in the argument.

The tests conclusively demonstrate Royal Purple performs poorly overall (in most key test areas). RP flat-out failed all but one of the viscosity tests to include viscosity after shear test, failed the copper corrosion test, performed the worst in the Extreme pressure and % shear down tests, as well as near the bottom in the load wear index and oxidation tests. It performed well in the 4-ball weld test and precipitated solids test. Overall it was only worsted by Mopar and Lucas synthetic gear oils - and not by much. Every conventional oil outperformed RP.

Amsoil WELL outperformed all of the other oils and it's cost was in the middle of the pack. RP was one of the most expensive in the pack. So much for getting what you pay for.

Other oils included in the test: Lucas (absolute garbage), Mobil 1, Castrol Syntech, Castrol conventional, Penzoil synthetic and conventional, Redline synthetic, Torco synthetic, Valvoline synthetic and conventional, Mopar and GM synthetic lubes. All synthetic lubes were 75W90 and the conventional lubes were 80W90.

Personal experience is also indespensible - and the failure of the rear-end of my former 1999 Grand Cherokee was directly attributed to oil failure - Royal Purple 75W90 installed by the dealer. What's worse is RP refused to even examine the evidence and would not back their product. I refuse to recommend any product from a company that doesn't back their product. I wish that test was available prior to letting the dealership install the RP. I was out of Amsoil at the time and the dealership was running a special on RP - what a bad choice.

If you want another true test of gear oils - ask S2KPUDDYDAD, he builds the best diffs available for the S2000 and uses Amsoil Severe Gear.

prancer

Thanks for the info. It was an interesting read!

But I already use Amsoil for my tranny and diff, what I am questioning is engine oil.

slipstream444

The subject matter is focussed on gear oil and the pricing you posted was more inline with Amsoil motor oil. ATM 10W30 (what I use) runs $6.70 under Amsoil's Preferred Customer Program (PCP - $20 a year to join).

Amsoil Severe Gear 75W90 is $9.85 and 75W110 is $10.60 under the Preferred Customer program.

Additionally, to be fair to Mobil 1 - with respect to this forum being about gear oil - their 75W90 tested out as the the number 2 gear oil. The only black mark for the Mobil 1 75W90 was the fact it failed the Viscosity After KRL Shear Test.

That's more than enough for me to stay with Amsoil SG for my diff - especially considering M1 (~$9) and Amsoil cost about the same (when you buy Amsoil at the PCP price). I'd still use Amsoil at nearly twice its current cost based on its performance. That's easy.

slipstream444

I'd stay with Amsoil. There is NO better 10W30 on the market.

RP like Lucas oil are all about marketing - no substance. Amsoil has consistently made the best motor and gear oils - for as long as synthetic oils have been marketed in the U.S.

prancer

Ill take your advice. I think I am going to make the switch from RP to Amsoil. We just got an Amsoil dealer in town, so there is even more reason to make the switch!

CharlesAP2K

Thank you slipstream444 for the details there. I just got back to my desk and it looks like you've cleared things up... I read that same link about 6 months ago when researching for a brand to switch to. Many people "talk" down on Amsoil because of the "Direct Sales" approach the company has. But anyone who truly understands Direct Sales knows that this is a great idea to begin with... By no means a reason to not use the product. I have researched their filters as well! Unfortunately I cannot spend the time right now to link all the info, but if you google amsoil it's all there. With that said...

My recommendation is to run Amsoil engine wash, change out the oil filter to an Amsoil nano filter, run 5 or 10w30 motor oil. I stuck with Genuine Honda Tranny Fluid and the Amsoil Severe Gear 75w110 in the diff. Not that I have anything against the Amsoil Diff Fluid, just heard enough good reviews on the Honda stuff to stick with it.

* Plus the stickers add like 5whp

Amsoil FTW

zoomspeed05

i use royal purple and it runs great

chef-j

I tried royal purple for my previous's car, just because i heard many postive feedbacks. But i didn't feel much diff than other oils that i've used.
But i'd would like to try amsoil for S2000 and see how it feels diff than OEM fluid.

Edit: oh also i heard good things about Redline on other vehicle. Not sure about S2k tho.

FASTSIIK

I used RP in my diff and less than a month later I had to replace it. Not saying that RP was at fault, it may have been coincidence, but i'm not willing to try it agian. I did like the motor oil though.

zeroptzero

I'm running Amsoil Severe Gear 75w110, it has a thicker viscosity than any 75w90 or 80w90 and is in the top end of the old SAE90 spec that was used when Honda first developed the S2000. Better hot temp viscosity will protect your diff. better, while still flowing well in cold temps which is also important given that our sumps are tiny.

I run Amsoil 5w40 in the engine and I love the way it runs with this oil, very quiet and smooth. I'm sticking with Honda MTF in the tranny though.