GREAT FORUM! I've read all kinds of things on my new 2006 GT. Thanks guys! And thanks to this forum I got free gas and a wash when they did my recall check. (3500mi...all OK...just new software)

OK....I read before that some notice the thing runs smoother right after an oil change. I've also read that Mazda doesn't approve of synthetic oil, though some of you run it any way. The Sticky was a great help!

Here's my question:

IF...the car runs better after an oil change (mine did at mid to high RPM) then doesn't that tell you that the 3500-mile old oil was broken down some and less effective? If not...you'd not notice the oil was changed?

Then, IF...the oil breaks down quickly in the Renesis, why should we NOT run a Mobil1? Couldn't synthetic only HELP?

Thanks!

 

This is gonna be good!

 

Yikes! Did I open a can of worms? Didn't mean too. I just didn't see this "twist" type of question on the sticky. I'm very curious to the members thoughts.

 

I'm just restating what I have read here by numerous folks.. many are respected as knowledgable on rotary engines.

Mobil1 has a reputation for being a good synthetic in piston engines.. but there is significant talk that it is not good in a rotary (possibly for the reason it IS good in a piston engine). The talk basically is Mobil1 isn't burning as it should during the combustion cycle, so you get sludge/carbon build up in the intake/exhaust ports.

(I'm sure I've just stated that all wrong, and will be corrected and flamed.. but anyway..)

My personal opinion, stay w/ non-synthetic.. or go with a botique synthetic like Red Line or Royal Purple.. very few problems have been stated or speculated with those oils.

 

Thanks Fray. Gotcha on the synthetic part.

What about the conclusion I drew? IF the thing runs better after an oil change then you'd conclude the old oil was "worn"?

 

No..you could conclude that the oil was dirtiER than new oil, and that the filter flows less than a new filter..and the combination of the two requires more HP to pump it, and more HP to move engine materials thru bearings and such as it would have more internal fluid friction to overcome.

The thing with synthetics, is the Viscosity Improver used to make the oil flow as manufacturers want it to. There are good ones, and better ones, and the better ones dont burn ashy and gummy.

Mazda COULD test all oil forever, or just say "dont use synthetic".

Since you generally only use Synth for longevity between oil changes, and the rotary burns oil at a pretty good clip by design already, youre wasting any good money put into synths as opposed to a good dino oil...to which NO failures have EVER been accredited to, ever, with good maintenance schedules.

Its not worth the cost or 1Hp to run Synth in your rotary motor..especially since considering piston motors with MUCH more internal friction to overcome, barely register gains on a dyno already.

 

Makes ALL kinds of sense to me! Thanks!

 

Thats because your oil was dirty like ^^^^^ said.

Anyway, the choice is down to you. Synthetic or not.

I would say, I want the best for my Rotary, and I use Full Synthetic Royal Purple ONLY. Why ? because I have excellent results, engine is smoother, and seems to rev faster.

and instead of crying wolf like most oil companies(Mobil, shell/quakerstate/pennzoil, etc), Royal Purple is one of the few that dare to say its OK to use their oil in Rotary Engine(Idemitsu is another) Yeah sure you can say *they just want sales* , but do you know they also carries the risk of being sue if they bs about it, oh yes we live in a country with full of law suits.

Im happy. No smoot in my tail pipe. what else can I say ?

 

This makes sense to me. Viscosity would seem to be an issue. Note that the US is getting the increased-oil-metering flash and recall. The US also has the 5W-20 oil "recommendation". Other countries use 5W-30. Those countries aren't getting the modification, as far as I've read.

 

Every car I've owned ran better after an oil change. Also after getting washed.

Remember Stephen King's "Christine?" The first thing the kid did to the car was change its oil. Made a major improvement.

Ken

 

Oh my God. Is this not true! Or....it always rides better after a new accessory gets added.

 

or worse if you botch the install.

 

You add horsepower for changing oil, according to GT4.

 

[jokie]

You also reduce weight in your car if you take a crap before you drive anywhere.

[/jokie]

 

I thought that you are not suppose to eat for 10 days before you drive ?

 

Curious, has RP paid for anyones engine replacement that has been tagged as a "wrong oil" failure and been denied warranty?

Its one thing to say "OK", its another to back it up.

 

Theres almost no way that you can blame an engine oil manufacture when your engine fails. Simply because they already did their job, to go thru all the testing process (paid to do)

but theres always a risk, and this *risk* can sometimes result in millions of dollars, is a risk that not everybody wants to take.

Do you know how hard it is to have one company to say its *ok*? RP and Idemitsu had actual experience in Rotary applications, thats why they have the confidence to say that its ok to use their oil in Rotary engines.

 

Rp Ftw!!!

 

I hope you were being sarcastic.

 

There are no reported failure of using Synthetics either, the picture Mazda showing is just a typical *I baby my engine and I have carbon deposit* thinggy. ITs a well KNOWN fact that if you baby rotary engines, you will get carbon deposit way more than pistons.

 

Why should they? There hasn't been an engine failure as a result of using their oil and no one out there, not even Mazda, can claim otherwise.

 

Carbon has been a rotary issue from day 1. That's why the side port exhaust wasn't developed back in the 70's. They tried it. Carbon buildup kept breaking side seals. Of course we've got better seal designs and oil metering now but the fact that carbon has always been an issue should really raise some eyebrows. I don't think anyone is going to claim that they were using synthetics back then which led to that problem. The Renesis has larger clearances on the side seals as well as a wedge shaped side seal just to remove carbon. Again, this isn't because they knew people were going to use synthetics. It is a problem with conventionals apparently. Blame is being put in the wrong place and too many people are trying to justify it.

 

From all I have heard I sway towards RP synthetic oil but at the same time I've seen the pictures from Mazda showing a new rotary engine clogged from synthetic oil. Mazda dose not say which sync. oil this was but it has to raise a few questions. The only real way to prove this out is to show some RENISIS Rotaries torn down after extended use with synthetic and show that no gummy carbon has accumulated. Until this happens we have no concrete proof.

 

I wouldn't want to use an oil that isn't formulated correctly, or well, even if it was synthetic, or conventional. Would you?