Royal Purple or Amsoil

[MOConnor]

Hello all I have a small problem. I want to use a Synthetic in my 03 . There is 30500 miles on the truck. Now I have been told that Royal is better then Amsoil. But a mech I know says that synthetic oil is all the same. I am going to put synthetic in my transmission,front and rear diffs and transfer case. But I need to know what one is better. This might start a war between the Purple people and the other guys... I also need to know what gear lube goes in the diffs. Well thanks for the help and you all have a safe and happy thanksgiving... ... ... ... ... Mike

 

[Wayne_C]

I have been a member for almost a year now, and this is my first post. I have learned a lot being a member here. As of the Amsoil and Royal Purple, I would like to know myself. I am running amsoil as of now, but have thought about switching to RP. One of my friends has ran RP in his f350 and the amsoil dual bypass system, his oil analysis at 70000 miles were the same as somone with 20000 miles on their truck! I also have the dual bypass system, but I have not done an oil analysis test. I have ran RP in a mustang before and the oil seems to have a more clingy texture to it than amsoil. The only reason why I chose amsoil is because I could get it cheaper, and I already get my filters from them.

 

[Vaughn MacKenzie]

Heh . . . there's never a shortage of oil wars! LOL



I don't think you'd go wrong either way between Amsoil and RP, both are excellent oils Mike. I haven't used RP but have used Amsoil in the engine and rear axle with great results on my trucks. The only cautions I would suggest is if you travel to hot climates avoid the Amsoil 5W30. Play it safe and stick with 15W40.



Vaughn

 

[RustyJC]

Both are Group IV (PAO - polyalphaolefin) base stock synthetics. Your engine will think it died and went to heaven on either.



Rusty (Delo 400 user in truck, but PAO synthetic user in all other vehicles)

 

[amsoilman]

But a mech I know says that synthetic oil is all the same.

Your mechanic doesn't know what he is talking about! Just like ANY OIL, Synthetics are not the same!



Wayne

amsoilman

 

[LightmanE300]

Wayne - look at the big picture - his mechanic pretty much did know what he was talking about for MOconnor's use - figuring he'd save him the trouble of pointless research... Regardless of small differences in additives etc, both RP and Amsoil will work fabulously in his truck, and he'll never know the difference.



With that said, go for the Mobil Delvac 1!

 

[EMD-Run8]

Oh boy, the slippery slope... ... ... ... ... ..... I like Amsoil. It probably is less expensive than Royal Purple (sounds like a monarch's underwear) but I understand it is good oil. If you can find a copy, Motorcycle Consumer News did a very in depth comparison of oils (both dino and synth) and it was interesting to see which oils stacked up and which ones didn't.

 

[DBogo]

amsoil is the best i run it in my suzuki Z400 and my 70 chevy C20

 

[C Schomer]

I've only tried one Ams product - 2k75w90 and got noises in my diff. at 13k miles. Tried RP 75w90 and noise stopped. I know it's not a very scientific comparison - Ams with 13k on it, compared to new RP. I should've been using a w140 all along, for my usage. I only used the RP 75w90 (in the diff) for a few 1000 miles and switched to RP 75w140, then later to 85w140. I've used all RP since - engine, diff and power steering. I tried 75w90 RP in the 5sp and it was TOO stiff. Thinking about trying Ams in it, next. I don't think it would take much to beat the mega$ Castrate stuff!! Shimmed up the end clearence at 32k and it's sloppy again at 75k. Yes, I did regular changes. Any Ams dealers in the SW Phx area? I've read the 2k 75w90 will take the chattering out of the 5sps and still shift good. Craig

 

[Buffalo]

Rusty CJ. I noticed in Your last reply that You use Delo 400 in Your truck and synthetics in Your other vehicles. May I, respectfully, ask why You made that choice. I have heard a number of times of people getting over a million miles using dino oil. For most of us, we will never see a million miles, or any where near that. So why spend the extra money on synthetics? Also, what are Your thoughts on using the factory recommended gear oils in the trans. and diff's. Thank You, for Your comments. Joe F. (Buffalo).

 

[anestech]

http://www.coximport.com/royalpurple/dyno.html



Also had a buddy that ran in in his SCCA non turbo 944, and gained a couple HP on the dyno when they made the switch.



I also saw an article in Corvette Magazine (IIRC) where they went from Mobil 1 (factory fill, 5w30) to a Royal Purple 5w30 and gained 5 HP and nearly 10 ft/lbs in back to back dynos after just a drain and fill.



That said, I run Redline through out my Tacoma... :shrugs:

 

[mberry]

I use RP in the differentials of my last 2 trucks and the sterndrive in my boat. No problems at all. RP is less expensive for me than Amsoil at the moment because I can go buy it off the shelf. I will be putting RP or Amsoil in the engine when the time comes. For me it is the convenience factor as well as money.



I have nothing but good things to say about both products.

 

[amsoilman]

Ten Reasons Synthetic Motor Oil Is Superior To Conventional Petroleum Oil

1. Superior wear protection…. Engines last longer

2. Improves fuel economy… More miles per gallon

3. Easier cold starts

4. Cooler running engines in high heat

5. Reduces engine deposits

6. Resists oxidation and thermal breakdown

7. Increases horsepower

8. Superior shear stability and film strength

9. Extended drain intervals produce environmental benefits

10. Reduces exhaust emissions



Wayne

amsoilman

 

[jimnance]

Synthetic lubricants used in commercial gear trains (transmissions, diff's, etc) have proven to be both economical and lengthen component life in tests involving millions of miles of testing by some of the largest trucking carriers in the country.



On the other hand, the economical life of a Class 8 (large over the road truck) is somewhere around 750,000 miles. They can run longer, but generally big fleets will turn them over within that time span. They have found that high quality conventional oil gives more than adequate performance to achieve engine life exceeding that number while being substantially cheaper. With oil change intervals approaching 20,000 miles in some cases, there is simply no compelling reason to use expensive synthtic lubricants in your engine. If it makes you feel better, it won't hurt the engine, but it will make your pocket book lighter. Also, consider that the typical life of your Cummins engine is around 300,000 miles. By that time the body of the truck will likely be falling off your truck anyway.

 

[rotts4u]

Oh boy, the slippery slope... ... ... ... ... ..... I like Amsoil. It probably is less expensive than Royal Purple (sounds like a monarch's underwear) but I understand it is good oil. If you can find a copy, Motorcycle Consumer News did a very in depth comparison of oils (both dino and synth) and it was interesting to see which oils stacked up and which ones didn't.

I wrote that article(s) so if you have some very specific questions feel free to ask me directly. Off the top of my head I seem to recall that the Royal purple oils were not as heat stable at Amsoil, Mobil and a few others.



Don Smith

 

[BHolm]

The trucking outfit up the road from my business runs 50,000 mile intervals on their class 8 Mack trucks with synthetics. That is double the interval and the oil is less than double the cost.

 

[jimnance]

The trucking outfit up the road from my business runs 50,000 mile intervals on their class 8 Mack trucks with synthetics. That is double the interval and the oil is less than double the cost.

The exception rather than the rule. If you look at the top ten carriers in the country I doubt you'll find one that runs synthetics in their engines. These are carriers that are run by professional managers that know how to turn a profit. Because profits are generally less than 5% of revenue in a pure trucking operation these men look everywhere for a dollar.



The fact that your friend uses MACK trucks tells me a couple of things. One, he is probably involved in off road or construction related services. Most of these firms are relatively small, usually less than 100 trucks. Also, MACK trucks have a reputation for building a very strong truck that wil hold up to the rigors of that type of work. A good thing, but he is not looking at the economics of a carrier that has over a thousand trucks in OTR operations. First, a large OTR (over the road) carrier can't afford the cost of MACK trucks. The deals that Freightliner, Volvo, and others make the unit costs much less.



Anyway, small specialized carriers tend to have higher operating margins and can afford to experiment with things that may, or may not pay off in the long run. Consider that the typical construction truck won't last much longer than 500,000 miles. They take too much abuse, and they tend to fall apart before the engine gives up.



I guarantee you that your average CTD run with Rotella, Delo, or other high quality dino oils will last as long, or longer than the body will last. Further, extending drain intervals to 50,000 miles because you are running synthetics with the super duper filter system that your local AMSOIL dealer sold you is flirting with disaster. Spend you hard earned money on something that will really benefit you. How about a built in Espresso machine? :-laf

 

[LightmanE300]

I think someone's been listening to a little too much molly hatchet. Please tell us in your oil expert opinion (I don't care about any other trucks or trucking other than CTD dodges) why people running bypass systems and extended drain intervals are 'flirting with disaster?' Talk about :-laf :-laf

 

[jimnance]

I think someone's been listening to a little too much molly hatchet. Please tell us in your oil expert opinion (I don't care about any other trucks or trucking other than CTD dodges) why people running bypass systems and extended drain intervals are 'flirting with disaster?' Talk about :-laf :-laf

It's a fact, do the research. All lubricant oil sufferers a breakdown of the molecular chain that gives the oil it's lubricating properties. Synthetic or conventional will suffer the break down of the chains. The only question is how quickly. Triple by-pass whammy whoopy bypass filters are fine, but in the end, when the oil breaks down enough it's starts failing to lubricate properly.



I don't know the relative rate of breakdown, though given some time on the net I'm sure I can find it. Does synthetic break down more slowly? Probably. The question is how much more slowly.

 

[LightmanE300]

Clearly from your reply you haven't done much research on the matter, so I wouldn't be throwing the word 'fact' around so loosely. . I've done plenty. I do regular oil analysis and the oil is in perfect condition. You can talk about 'chains' all you like, but I have a very high tbn, concentration of additives, and extremely low wear metals and soot. No reason to dump perfectly good oil.