... was quite an experience. I drive up for my 3,000 mile change and literally every sales guy and tech stops to look (they don't get many RX-8s around here). I speak to the Service Advisor and follow-up to my question about putting synthetic in my car. She goes to the Head Tech, who says, "No way, only regular according to Mazda."

I mention this to the Service Manager, who I've spoken with before on this. He says, "When did they announce that?" Then he, the Service Advisor, the GM , and the Parts Manager all start pounding their internal access to Mazda corporate to find out more. Finally, they all agree that since the Castrol 5W-20 synthetic oil meets all the required specs for the RX-8, there is NO issue with putting in synthetic oil. Nothing from corporate on not using synthetic. Even the Head Tech now agrees after getting involved.

The Parts Manager says he had heard in training, as I had mentioned to the Service Manager when we first spoke, about the only issue with synthetic was of carbon deposits. The Service Manager again says, "I've seen high-mileage RX-8s in here with no problems with that at all".

Botom line- GREAT customer service (5 people to help out) and synthetic should be fine in our cars!!!

 

Yeah, I think we've all agreed not to agree on this subject.

 

I use Synthetic and Only FULLY (notice) Synthetic

10,800 miles now w/o problems. Im going to have another oil change soon probably raound 12K miles and of course. Synthetic Again !

 

Actually most of the arguments that have evidence backing up their position support synthetic use. Typically the people against it are the ones that go by hearsay with no proof to back it up. To worry about carbon deposits with synthetic is actually backwards. This is misinformation that has spread around. You are far more likely to get carbon deposit from conventional oils. Carbon deposits are more likely in less refined oils as they happen as a result of the impurities in the base oil. The higher the class of oil, the more pure the base. The synthetics are the higher classes Group IV and Group V while conventionals are Groups I-III. Some Group III oils have been called synthetics but that isn't accurate. They are better than group I-II though which is what most people use. The lower the group, the more impurities in it which affects breakdown, and deposits. It doesn't really make sense that an oil with more purity would leave more deposits since they are largely caused by impurities. This statement holds true.

Keep using that synthetic. Your engine will last longer for it.

 

There is no proof that it is ok. Mazda does not recomend the use of synthetic.

 

There is no proof that it isn't okay either. Mazda just "recommends" certain oil to "cover their ***" so to speak.

 

There are endless accounts of it being OK. I have no idea what you are talking about. There is tons of evidence that supports it's use. There is no evidence that it is bad. None. Nowhere. No one can provide it. Even Mazda uses synthetics in their own race cars. I don't want to hear any crap about some oil being "special" in regards to the rotary. That's pure crap. I've seen the oil analysis of Idemitsu and lets just say there's nothing in it that isn't in any other synthetic out there. It's all marketing and people are falling for it. Idemitsu actually has unusually high amounts of molybdenum in it. This substance while good for lubrication will also not stay in suspension indefinitely and will settle in the pan and other areas of the engine. This is something that should worry people yet people say it's great stuff purely because it's marketed as such and Mazda used it. It was good for track use but not street due to the settling issues of the molybdenum.

 

It's true that there's nothing in the owner's manual saying you can't use synthetic oil. However, on the DVD that came with my 8 they specifically say to use "non-synthetic" oil.

Now I've read thread after thread on this subject and, frankly, I am torn about what to do. On one hand, I believe people like rotarygod really know their stuff and are probably right—synthetic oil is better, synthetic oil is fine.

On the other hand, there must be a reason why the DVD specifically says to use a "non-synthetic" oil. Maybe it's a stupid, legal, cover-your-*** reason; maybe there's a technical reason—I'm not an engineer; I don't know. I would feel better about using synthetic if I knew exactly why Mazda says not to. That's all I ask. I'd like to know, specifically, why Mazda says "use non-synthetic oil".

 

At SevenStock 8, some of us talked to the engineers in the RX-8 program from Japan who said that Synthetic is fine to put in the car.

The reason Mazda doesn't "recommend" it is because several studies out there have shown that not all synthetics are made the same. Some are actually barely worthy of the name 'synthetic'. Because of these inconsistencies, Mazda just chose to go with conventional oil
Too much of a hassel from them to actually list which ones to use and which ones to avoid....

I have Royal Purple Synthetic in the tranny / differential of my car and it works great. The only reason I haven't gone to Synthetic for the engine is because I'm too lazy to do my own oil changes and I get discounts at my local dealership. I might look into just taking some Royal Purple with me from now on....hmm....

 

Couldn't agree more... have read many of your posts (EXCELLENT!!). As far as synthetic, have had in my last 5 cars with NO problems... all I use or trust... I'm an Amsoil fan!!!

 

Since you're rotarygod do not take it offensive, but isn't that true that mineral oil burns cleaner and thus, since it is actually being burned it is better than synthetic for rx8? As everybody knows synthetic oils have higher resistance to burning. And the fact that mazda did not recommend using synthetic is because of exactly that.

 

So which oil is the highest grade of synthetic?

 

With combustion temps in the 2200 degree range, there is no oil that would resist flashing; moreoever, a higher resistance to burning does not mean it will not burn, rather the oil is more stable at elevated temperatures. I have used synthetic for the last 10k (Royal Purple) with no problems.

 

no.


no.

 

thank you

 

Ok, so after much (too much) reading on this topic, I have been persuaded by the pro-synthetic crowd (especially rotarygod) that synth is fine, and indeed better. However, dino is the path of least resistance. So my question is: just how much difference does it really make? I mean, assuming I do regular oil changes with either type, what actual difference would I see in my car if I switched to synth?

 

As Joey would say, this is all a moo point.

That is if you change your oil every 3000 miles, there is no diff. between the two.

There are exceptions, on my boxer twin (BMW bike), BMW insists on mineral oil only, to the point that they'll void the warrenty if I put in synthetic. On my last boosted Passat, VW insisted on switching from mineral to synthetic because of sludge problems, but then the synthetic started leaking through the gaskets. Point is, the only reason for the sludge problems is that they weren't changing oil at 3-5000 miles. I use a semi synthetic on my Fireblade, but thats a 929cc 12000rpm 4 cyclinder that does 150hp.

In each case, follow the manufacturers instructions on oil type, but never on change intervals.

 

We all get to this question sometime during the rotary ownership experience. I got to the question about a month after joining the forum.

If you are wondering whether or not to put synthetic into your engine, may I suggest you do a search on RG's posts. Use the word "synthetic" in the search field. Feel free to search my posts on the subject too.

I honestly don't know why you continue to post in these threads, RG!! You must own shares in Royal Purple??

 

Hey Gomez, you were right, nobody gave me any clue on how to re-wire the DSC/TCS switch.

I'll take back my useless comment!

 

when u purchase a product, u should always (1) follow the official product documentation/ manual for it published by the manufacturer and (2) use some good old common sense.

if a dealer's mechanic tells u that it's ok to fill your gas tank with Tide laundry detergent, and after hours of research and discussion they still conclude that it's safe and tell u u can do it- even though the manufacturer's documentation clearly says that you should not- are u still going to do it? it doesn't mean that putting Tide in there won't work. it just means that if u're going to deviate from the product manual, then it's at your own risk.

seems like a no brainer to me.

 

Hahahaha, no worries.....

 

OK, I'll bite. But let's make this short.

PRODUCE THE DOCUMENTATION THAT SAYS CATEGORICALLY NOT TO USE SYNTHETIC.

 

The most compelling argument against synthetic is that it's a waste of money if you change your oil at the normal frequencies.



IMO

 

The non-synthetic Mazda Rotary Oil I use has just had a price rise. It is now more expensive than any synthetic I see in the stores.




And before you ask, no.....I don't think this oil is available in the States.