Wow so it IS true! Thanks for clearing that up. It's crazy the amount of misinformation out there.

:rolleyes:

... and with regards to that 2006 TSB, as I understand it, they were still trying to isolate the reason for those carbon deposits that would literally cause some of the low compression engine failures common to the S1 Rx-8s. the S2 engines/cars are still pretty young, but i'm curious to know if they, too, will be as bad as the S1s were. i'm sure the synthetic "warning" would officially apply to them as well though.

I know, Brother. I know ....

I run full synthetic

Ya I use full synthetic and my car is just a street car as of right now , so that's bad?

Since I don't drive my car as a daily, I use Idemitsu Engine Oil 10W and premix as well...
Yes it's a little more expensive...but prefer this over a motor rebuild

^Sorry, but this is nonsense. Inferring that your magical and insanely expensive rotary oil will somehow prevent a rebuild is ludricrous. Especially since the rotary very rarely suffers from an oil related failure regardless of brand or type of oil.

Mazdatrix's answer:
Using Synthetic Oils in Rotary Engines

^Their opinions...along with qualifications and disclaimers, are provided to you free of cost. But they sell Indemitsu at between $90 and $108 a case, plus shipping. ;)

AND????....Bro,what's your beef with Indemitsu???....i'm sure your advice to the original question, can be slightly less opinionated and more along the lines of what oil do you use....

No beef. But I think it's pretty clear......."Bro", my opinion is that it's not worth the money. Not even close. And that's at least as valid as you suggesting it will protect you from having to rebuild. My experience with rotaries goes back to 1981. How about you?

AH!...the decades of experience card!....nice!
well Mr. Rotary....besides price, what else is inferior about idemitsu vs what you currently use (or have used since your first 12 cabbie)?

:icon_tup: +1

This question has bothered me since I bought my FC. Thank you guys for dispelling the myth that all synthetics are a death warrant for rotaries.

There is no documented proof that synthetic engine oil makes a street engine last any longer than it would with quality mineral oil. If your sole reason for using synthetic oil is to avoid a rebuild on a street car, then you are completely wasting your money. If you doubt this, then I would encourage you to contact Idemitsu to see if they are willing to warranty your engine past its normal 100,000 to 200,000 mile lifespan when using their oil.

Synthetic oil has an advantage in severe environments, such as endurance racing or driving in extremely hot or cold weather. Your area does not experience extreme temperatures.

That's pretty standard pricing for synthetic oil. In fact, I have seen some US vendors pricing synthetic oil for 50% more money than that. Considering that Idemitsu is top-quality Group V based oil, I think that is a pretty good deal... assuming that synthetic oil is worth it for the application.

1. I've heard this tune before, so before we get to the crescendo, let me say this now. let's turn the fire down a bit. as much as I may love to instigate, I can't do that here. ironically, this an oil discussion that doesn't involve war. (imagine that .... :)) so we don't need any arguments past making your respective points. you can even throw a fact or two in there if you wish as well. copy?

at the end of day, you buy Idemitsu and it seems to please you. he doesn't buy Idemitsu and that seems to please him. end of story. agree to disagree.

2. not for nothing ... unless I missed it, I don't recall seeing him state or imply that Idemitsu was inferior.

It seems enough opinion have been thrown around, I feel I might as well throw my hat into this ring.

I run Idemitsu.

I have a few reasons. My FC was running synthetic when I bought it. The individual I purchased her from had built multiple rotaries and even raced a bit. Also, his last rotary build went about 240k miles before giving out. So I trusted his opinion on the rotary oil debate. He also warned me that I'd hear a lot about how synthetic gunks up rotaries but that it hadn't been the case for decades.

So here's how I see it.

While true that synthetics used to gunk up rotaries, synthetic oils have gotten much better and Idemitsu has all but eliminated that concern. Synthetics are made to protect better under heavy use and at high heat and was originally developed for jet engines to protect at extreme high heat and at extreme engine speeds. As pointed out earlier by others, for boring day to day driving, it's unnecessary. If I only did that kind of driving though, I would have bought a Civic. I bought this car because I can take it to a track or the hills on the weekend and flog it around some corners. I have already sacrificed practicality, fuel efficiency and being about to take my car to most shops in the name of performance, so why not a few extra dollars on top shelf fluids. Seems like a dumb place to start skimping.

As for why Idemitsu as opposed to other synthetics? A case of Idemitsu comes to about $9.90 a quart and is specifically made to burn inside a rotary while still protecting like a regular synthetic. That price is about the same as Mobil One or Royal Purple, so it makes no sense not to use it. I don't have to ship it however, so that affects the overall cost.

Basically, I bought and built my car to have fun. If I'm going to drive it hard, I want oil made to keep up.

For the record, I have nothing against Indemitsu....just think that if you WANT to run a synthetic, there are group IV oils out there that are readily available, for much less and ultimately perform just as well. Unless your car is a track king, living above 6k, it's marketing...IMO. I also think that even some enthusiasts might be tempted to go longer than they should (normally would) if it has to be ordered, shipped and especially if they're being that spendy on Indemitsu. I think I said earlier in this thread that IMO, for a streeted car regular relatively close change intervals are more important than what type or brand of oil you use.

To jaggie....you have my apology for pulling the experience card. You're right. And it always pissed me off when someone did that to me. Experience and and knowledge are two different things. Again, sorry. I just hate the 'bro' stuff. Kind of like being called "dude". I guess it's a trigger of sorts....I get that alot at work.

Other thing is that syntetic work far BETTER on turbos......cause mineral is more exposed to cooking

I run a turbo on my FC I haven't bothered with synthetic oil. But I've been contemplating it myself

Group IV oil is typically about the same price as Group V at the consumer level. If you see cheaper oil, then it is probably Group III fake synthetic, or it is a Group IV blend with a lot of Group II and/or III base stock. I am of the opinion that Group V is superior for endurance racing engine oil.

Yes, it is a marketing scam. However, the more money these guys give to "big oil", the more money I make, so at least there is an upside to this, lol.

That is true. However, all of the RX-7s come from the factory with water-cooled turbo bearings, so coking is not a problem as long as you use a quality oil. Once again, synthetic oil is not necessary for 99% of the people on this forum. However, if you have downgraded your turbo to a cheap aftermarket turbo that is not water-cooled, then you may want to use synthetic oil, depending on how you drive your car.

I used Mobil1 in my ITA race car for years with no issues. I premixed though. Got many years and track records out of one engine. And it saw 8K regularly.

Personally, I run a non synthetic simply because I'm just driving it on the street right now. When I get around to doing some serious auto-x and track days I will run synthetic but I wouldn't go any cheaper than royal purple or redline just to be sure it will burn properly. This is just personal preference. Be careful of what you read on the forums on this topic because you can easily get into a heated argument that has already been done a thousand times haha.