Rotary help. 2010 series 2 RX8

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Recently picked up a super low miles (37k) series 2 RX8. Bought the PO out of a loan he could no longer afford and got the car for about half its actual value. I own it outright. This is my first rotary car. The 2009+ rx8s are called the series 2 cars (series 1 being 2004 to 2008) because they have the 4 port engine, not the 3 port engine. Unlike the series 1 cars, a well maintained series 2 car will do 120k before a rebuild.

Some background on the car:
2010 RX8 sport series 2 4 port Renesis
BHR ignition coil upgrade
Racing beat catback exhaust with Agency Power cat delete pipe
K&N typhoon V2 intake
Stance XR1 coilovers with swift spring upgrade
I premix fuel with .5oz 2 cycle engine oil per gallon at each fillup
Stock OMP

What oil should I run in this car? People in the community say everything from 5w20 conventional, to 15w40 conventional, to all kinds of synthetics. Some people claim conventional oil is required and synthetic will ruin the engine, and some claim synthetic is 100% safe.

Any rotary guys/ladies here? What say you?

20181205_083815.jpg
 
You have 3 kinds of synthetic. There is group III+ (includes Gas to Liquid) , group 4 and group 5 Since in the good ole USA all 3 are marketed as syn, a given brand may change groups without needing to nitify to the end user. Many Syn are blends of these 3 and the blend ratio may change without notice too. To meet ever more severe specifications some of the higher groups are blended into conventions oils. If this engine is sensitive to a particular oil group, you really must be careful since things always change

Oh and good buy, l love the way those cars drive.

Rod
 
Remember that rotaries burn oil, it's part of how they function and not a sign of wear unless it's extreme. I think they are also very picky as to what oil to use this is due to the seals at the apex. I'd check with a mazda dealer or inquire in a Mazda Forum
 
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Originally Posted by Pelican
Remember that rotaries burn oil, it's part of how they function and not a sign of wear unless it's extreme. I think they are also very picky as to what oil to use this is due to the seals at the apex. I'd check with a mazda dealer or inquire in a Mazda Forum


No one on the Mazda forums agree. Some say conventional, some say synthetic. Some say light, some say heavy. There are 10s of thousands of pages of oil threads on the RX8 forums and no one can agree. The only generally agreed upon thing is that you should premix your gas with 2 cycle engine oil, which i do.

Part of keeping these engines alive is keeping the oil changed often. Mazda recommends 3000 miles and most people agree. (you only change about 50% of the oil in the car due to all the oil coolers and lines) If I went with a quality "conventional" like mobil super or castrol gtx and change at 3k miles I assume i'd be fine.
 
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I have no Mazda experience , so I am sorry , I can not help . But it is an interesting question . Please report back if you ever find a definitive answer .

I remember reading about the rotary engine , in Popular Science or Popular Mechanics , as a teenager .

Thanks , best of luck to you , :)
 
Originally Posted by WyrTwister
I have no Mazda experience , so I am sorry , I can not help . But it is an interesting question . Please report back if you ever find a definitive answer .

I remember reading about the rotary engine , in Popular Science or Popular Mechanics , as a teenager .

Thanks , best of luck to you , :)


Thanks! Will do! I think that, due to the fact that people have high mileage rotaries and swear by different types of oil, its likely not that important what you run, as long as you change it often.
 
Originally Posted by rooflessVW
Castrol GTX 10W-30.

Ditch the K&N.

Run it to redline frequently.


I haven't got the stock airbox. The photo shows what my intake looks like (not my car). I see the 10w30 recommendation frequently. Would you go thicker in the summer for autocross/track days?
I try to redline it each time I drive it at some point.

[Linked Image]

But mine has the heatshield like this including the stock ducting that pulls air from the grille area:
[Linked Image]


Should I get an intake more similar to the other common design for these cars like this:
[Linked Image]
 
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I just mean the filter itself. K&N intakes are well designed, but the filters leave a lot to be desired.

I put an aFe Pro Dry S on my K&N FIPK:

IMG_20181206_150747.jpg
 
I had a 2011 R3 until just this past October. I researched the crap out of this and cut through a lot of BS.

To make a long story short, there only seem to be two worthwhile engine oil options for this car:

1. Idemitsu Racing Rotary Engine Oil 10W-30
2. Any GF-5 5W-20 non-synthetic.

As far as I can tell, the problem with synthetics isn't with the basestocks per se; it's the combination of certain synthetic basestocks with certain additive packages. Running a GF-5 5W-20 non-synthetic is a really easy way to avoid all that, which is probably one reason why Mazda insists on it.

Idemitsu was Mazda's lubrication partner for the rotary-powered 787B race car, and they've published some of the definitive papers on Wankel engine lubrication. They know more about this than anyone other than Mazda. Their rotary engine oil is a full synthetic, but with a lot of ester content, which should provide good self-cleaning. What really separates it from other oils is its additive pack. It uses a lot of anti-wear additive and a fat slug of friction modifier (moly), but doesn't go overboard on detergents/dispersants. That allows it to keep ash levels low when it's burned, and ensures that the detergent/dispersant additives don't interfere so much with the AW/FM, while retaining enough cleaning ability for short-to-moderate OCIs. Most oils are the opposite: they have tons of detergent/dispersant for medium-to-long OCIs, and then manage ash levels by lowering AW/FM. Or they just have a lot of everything, and form a lot of ash as a result. That's a lot more likely to be true of a synthetic oil, which is probably another reason why Mazda insists against them.

The only problem with that Idemitsu stuff is is that it's expensive. Compared to a GF-5 5W-20 non-synthetic with shorter OCIs, I figured it'd have to extend the life of the engine by 20-40% to be worth the money. That seems like a bit of a stretch.

The idea to use heavy oil seems mainly to come from a desire to protect the gears and bearings better than a thinner oil can. There's some merit to that idea. But try asking someone who advocates thicker oil whether they have any evidence that it does what really counts, i.e. make the engine last longer between rebuilds. If you get an answer, let me know. I've tried that many times and gotten nothing.

The stock oiling system, including the MOP, was designed for xW-20 and xW-30 oils. Mazda's own Renesis-specific oil, sold only in Japan, is a 0W-30. Japanese dealers put 0W-20 in it all day. In Europe, Mazda recommends an ACEA A5-rated 5W-30 -- but there's no indication that that's for any reason other than to cope with longer OCIs.

There should be plenty of xW-20 and xW-30 synthetics that'll work in this car. I've just never found enough evidence that they'd be worth the money over a good GF-5 5W-20 non-synthetic.
 
Originally Posted by rooflessVW
I just mean the filter itself. K&N intakes are well designed, but the filters leave a lot to be desired.

I put an aFe Pro Dry S on my K&N FIPK:


Should I grab a big [censored] one like is on my car now or just any average sized one that fits in the box?
 
Originally Posted by d00df00d
I had a 2011 R3 until just this past October. I researched the crap out of this and cut through a lot of BS.

To make a long story short, there only seem to be two worthwhile engine oil options for this car:

1. Idemitsu Racing Rotary Engine Oil 10W-30
2. Any GF-5 5W-20 non-synthetic.

As far as I can tell, the problem with synthetics isn't with the basestocks per se; it's the combination of certain synthetic basestocks with certain additive packages. Running a GF-5 5W-20 non-synthetic is a really easy way to avoid all that, which is probably one reason why Mazda insists on it.

Idemitsu was Mazda's lubrication partner for the rotary-powered 787B race car, and they've published some of the definitive papers on Wankel engine lubrication. They know more about this than anyone other than Mazda. Their rotary engine oil is a full synthetic, but with a lot of ester content, which should provide good self-cleaning. What really separates it from other oils is its additive pack. It uses a lot of anti-wear additive and a fat slug of friction modifier (moly), but doesn't go overboard on detergents/dispersants. That allows it to keep ash levels low when it's burned, and ensures that the detergent/dispersant additives don't interfere so much with the AW/FM, while retaining enough cleaning ability for short-to-moderate OCIs. Most oils are the opposite: they have tons of detergent/dispersant for medium-to-long OCIs, and then manage ash levels by lowering AW/FM. Or they just have a lot of everything, and form a lot of ash as a result. That's a lot more likely to be true of a synthetic oil, which is probably another reason why Mazda insists against them.

The only problem with that Idemitsu stuff is is that it's expensive. Compared to a GF-5 5W-20 non-synthetic with shorter OCIs, I figured it'd have to extend the life of the engine by 20-40% to be worth the money. That seems like a bit of a stretch.

The idea to use heavy oil seems mainly to come from a desire to protect the gears and bearings better than a thinner oil can. There's some merit to that idea. But try asking someone who advocates thicker oil whether they have any evidence that it does what really counts, i.e. make the engine last longer between rebuilds. If you get an answer, let me know. I've tried that many times and gotten nothing.

The stock oiling system, including the MOP, was designed for xW-20 and xW-30 oils. Mazda's own Renesis-specific oil, sold only in Japan, is a 0W-30. Japanese dealers put 0W-20 in it all day. In Europe, Mazda recommends an ACEA A5-rated 5W-30 -- but there's no indication that that's for any reason other than to cope with longer OCIs.

There should be plenty of xW-20 and xW-30 synthetics that'll work in this car. I've just never found enough evidence that they'd be worth the money over a good GF-5 5W-20 non-synthetic.


Thanks for all this awesome info!

I'm all about shorter OCIs so thats not an issue for me. What GF-5 non-synthetic 5w20 do you recommend? Any reason to not go 5w30 GF-5?
 
Few other points unrelated to oil:

1. You have a 6-port engine, not a 4-port.

2. The BHR coil "upgrade" isn't really an upgrade. The coils themselves last longer, but LS coils have been known to underperform the stock coils unless the ignition dwell times in the ECU are increased. And most importantly, there's no evidence that an engine with BHR coils will outlast an engine with stock coils changed every 30k miles.

3. Definitely go back to the stock intake. Maybe you can trade that K&N for one straight-up.

4. Premix: again, zero evidence that it extends the life of a Renesis engine with a properly functioning MOP. It's not bad but you might as well save your money.

5. S2 engines definitely seem more reliable than S1 engines, but don't plan on running 120k before a rebuild. Budget for 70k-80k just in case.

6. Please, please consider reinstalling a cat. You can probably find a used stock one for cheap. Uncatalyzed rotary exhaust is really, really nasty.
 
Originally Posted by TinyVoices
Thanks for all this awesome info!

cheers3.gif


I loved my R3 and I miss it dearly. Happy to help another RX-8 owner.


Originally Posted by TinyVoices
I'm all about shorter OCIs so thats not an issue for me. What GF-5 non-synthetic 5w20 do you recommend? Any reason to not go 5w30 GF-5?

I like Mobil Super. That's what I ran when I had my R3. It's one of the cheaper options and it seems to have really nice specs: http://pqiadata.org/MobilSuper5W20.html

Oil viscosity is like tire width, spring rates, and fuel octane: you want as much as necessary, but no more.
wink.gif
A GF-5 5W-30 should be fine if you really want to run it, but it's just thicker for no good reason.
 
Originally Posted by d00df00d
Few other points unrelated to oil:

1. You have a 6-port engine, not a 4-port.

2. The BHR coil "upgrade" isn't really an upgrade. The coils themselves last longer, but LS coils have been known to underperform the stock coils unless the ignition dwell times in the ECU are increased. And most importantly, there's no evidence that an engine with BHR coils will outlast an engine with stock coils changed every 30k miles.

3. Definitely go back to the stock intake. Maybe you can trade that K&N for one straight-up.

4. Premix: again, zero evidence that it extends the life of a Renesis engine with a properly functioning MOP. It's not bad but you might as well save your money.

5. S2 engines definitely seem more reliable than S1 engines, but don't plan on running 120k before a rebuild. Budget for 70k-80k just in case.

6. Please, please consider reinstalling a cat. You can probably find a used stock one for cheap. Uncatalyzed rotary exhaust is really, really nasty.



I have the cat, I have just heard from all the forums that they fail easily and get blocked up and cause a ton of issues, hence everyone running cat deletes. If that isn't true, i'll throw it back in.

Also thanks, i'll go for mobil super 5w20.
 
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Originally Posted by TinyVoices
Originally Posted by rooflessVW
I just mean the filter itself. K&N intakes are well designed, but the filters leave a lot to be desired.

I put an aFe Pro Dry S on my K&N FIPK:

Should I grab a big [censored] one like is on my car now or just any average sized one that fits in the box?

Give aFe a call and they'll make you whatever you want - or they may make it already. Your intake looks awesome.

I'd try to find a similarly sized filter but a smaller cone-style wouldn't hurt anything.
 
Originally Posted by TinyVoices
I have the cat, I have just heard from all the forums that they fail easily and get blocked up and cause a ton of issues, hence everyone running cat deletes. If that isn't true, i'll throw it back in.

Oh, it's true alright. But mainly because people flood their engines, drive way too long with their engines running like crap, and then keep driving after their cats have clogged up. Often they don't stop until the cat glows after short drives or the engine just won't run. By that time it's far too late.

S2s are less susceptible to flooding and poor running, and the S2 cat is bigger. Plus, the symptoms of a bad cat are pretty obivious once you know what they are; the car basically just runs out of breath at high RPMs. If you stay on top of things, you'll be fine. Even if the cat does fail, you can catch it and fix it long before it takes anything else with it.

My R3's cat failed at ~54k miles. The failure appeared literally within hours of when I picked the car up from an incompetent dealership (airbag recall). Then I drove on it for like 2k miles while trying various troubleshooting steps because I wasn't getting a CEL and didn't know better. The engine ran another 20k miles before compression fell below Mazda's spec for warranty replacement -- but it never got bad enough to cause any starting or running problems. And I know for a fact that compression wasn't the best when I bought the car at 21k miles -- probably because the car had been a dealer demo or something for like a year and a half before it was sold.

But yeah, it is a possibility. You just have to weigh that against the toxic crap you're spewing without a cat. For me, it's a no-brainer. I refuse to be "that guy". If I had owned the car longer, I probably would have started keeping an eye out for a good used stock cat that someone was selling for cheap, to keep as an extra just in case.

Your call.
 
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