well guys i am new to rx-8 club n proud to be a new member/driver! i've owned a 2004 Mustang GT 5spd for about a year. then, wrecked it in the snow, ouch! i was so intent on getting another mustang its ridiculous. then i found this sexy black bombshell, drove her one time n was sold! i bought my rx8 about a month ago and i was very skeptical about actually owning one. i've heard this n that about its maintenance n how its unreliable but once you drive it. . the thoughts go from idk if i want this car to. . what maintenance n how much ? lol so i've now had my rx-8 for a month, enough to rack up 1,xxx miles, n this car amazes me on a daily basis! i just want to say kudos to this (what i once called a jap POS) incredible masterpiece. ROTARY where have you been my whole life ? no cam, crank, valves, pistons, etc, ? AMAZING! Wankel was def smoking the good stuff.

P.S.- jus hit 75,000 still runs strong but i worry daily. any tips for care ? this is my daily driver for now. and can anyone give a straight answer on oil! 5w-20 not cut it ??

 

Anything higher than 20w, drive the wheels off it, don't shut it off cold, check oil every other fill up since you should know it consumes oil by design.

That's all the basics you need to know.

Just a tip, search for your answers beforehand since the discussions on here for oil, and everything else all the way to asking someone what's up their butt is very intensive.

 

Congrats..welcome to the addiction! There's much you will hear, lot's of dis-information, but plenty of good info as well...get ready. With 75K your car should get checked out for routine maintenance that might need to be done, plugs, filters, fluids, check compression, pads, rotors, etc...much like any car.

As for oil, I don't think anyone can give a straight answer backed up by facts that can't be refusted by someone else with differing opinions. Read and make up your own mind as to what you are comfortable with. E.g, I use synthetic Idemitsu 10-30 now, but I've used dino too. Does it matter which? Who can say as each owners situation and use is somewhat different as are their results. I've always felt 5w-20 dino was just too thin for engine longevity, esp. in a warmer climate.

 

congrats and welcome

read the stickies here because they have a ton of good info about the rx8 and rotaries. They will be able to answer just about any question you can come up with.

 

I use 5W-30 and im in Texas... I really dont want to go anything higher than that, I really dont need 10W-30 because, well its Texas and I dont need a better Cold start, it never gets that cold. I would buy my Royal Purple in 5W-40 but thats hella $$$... 10W-30 is about the highest you want to go, the clearances in the 8's Renesis rotary engine arent like as big as they were in the 13B in the RX7... Goodluck and glad you love the 8

 

def think im gonna go 5w-30 next oil change! i've always ran thicker oil in all my piston vehicles n now i will with my rotary. trust me fellas i've searched lots, its just hard to get past half the retards.

racing beat lightweight rotors ? 9.2lbs to 9.0lbs. .whats the pros ? higher revs ? (of course less weight to move around) worth the time ?

 

congrats and welcome

 

Welcome to the madness

 

gratz. and if you are like the rest of us new owners, you are probably itchin to go take a ride right now lol.

 

for oil i would stick to what mazda says in the manual and on the oil fill cap. Each rx8 comes from the factory with an 8 year 100,000 mile warranty on the engine so if the engine craps out theyll give u a new one for free. But they will also try and find a reason NOT to give you the engine, if they find out u use different oil than what they reccommend they can easily tell you thats why the engine broke and youll need to buy a new one yourself

 

As an engine builder and rotary mechanic of 10 years, I can say that you have no idea about what you are talking about. In fact, you are saying things totally backwards.

You live in warm/hot texas. You need thicker oil. Thicker oil is better for hot areas, thinner oil is better for cold areas.

The clearances in the renesis are mostly the same (bearings, apex seals, corner seals, oil control rings) or looser (side seals) than in the previous rx7s.

 

Um, no. They cannot do that. Recommending is not the same as saying required. You can easily refute that and they have no argument against a manual that recommends but does not require a specific viscosity.

Just make sure you keep your oil change receipts showing you or someone else did them for proof if you ever need to have your engine replaced and you'll be fine.

 

Run at LEAST 10 weight...I personally run 20-50 in all my rotaries, always have, always will. Bearings always come out looking mint. I have some pictures of torn down renesis' using 5 weight, and it ain't pretty.

You're looking at $500-1000 for balancing and lightening of the rotating assembly, and another $1000-2000 for seals and (possibly) engine assembly by a builder. Plus time, tools, and fluids to remove/install the engine. Does that sound like a worthwhile investment for the ~5-10whp you'll gain from a lightened and balanced rotating assembly? Usually that procedure is done to increase redline, BUT this also usually requires engine porting and computer tuning to increase rev limit and fuel curve.

Bottom line, the renesis for the most part "is what it is". You can do "full exhaust", intake, tuning, pullies, flywheel, and maybe gain 20whp on a good day. Or you can spend 10 grand on a relatively unreliable turbo setup and crack an iron housing or break apex seals in the engine, but make +75rwhp for a few months in between.

 

Welcome to the club. Enjoy the car!

 

this sounds like it's on the money...

i would add that the BRH ign kit will give you smoother running and reliability (stock coils fail a lot, as is documented by many)

...and that since you live in a hot area, an upgraded water pump and radiator would improve your engine's lifespan a bit.

rx-8's are hot looking cars, and love to be maintained. much like many of the great women out there lol :D

 

I dont remember if I meantioned this but this is all from what I was told by a buddy who worked at Rotary Performance... From what I heard from him the Renesis's clearances are alot smaller than in the 13B found in RX'7s (which allowed them to use thicker oil)

Now we all know thicker oil protects better (assuming it gets to all the right parts) but from all that ive read the last 2 years the main problem with the rotary engine failing isnt the oil, its the poorly designed Renesis engine with only having 2 oil injectors... Oil has problems reaching the center of the Apex seals. Carbon is also a big deal as well... wouldnt a thicker oil have more problems getting to the center of the seal?

Its not the thickness of the oil, the oil is doing its job (to a certain extent, I dont agree that 5W-20 is thick enough, which is why I use 5W-30, I was thinking about going to 10W-30 though ), its the poor design thats holding it back and causing the failures.

I do NOT doubt your knowledge nor am I disagreeing with you, because I DO know oil breaks down as it gets hotter etc but dont you think Mazda would of specified 20W-50 if oil was the problem or if thats what the engine called for? Thats pretty thick oil... I think the Mazda engineers know a little more than you do (not trying to be rude, but they have made the rotary competetive to pistons in only like 50 years of development, that says something...) about the engine, because they designed it. They gave different regions different oil weights but I cant see 20W-50 doing a very good job at lubricating the small parts and gaps. Granted you would probably know more than I since I have never tore down a Rotary nor have I had as much experience as you.

Now since I dont have my friend here to help better explain I cant really argue much past that.

Please feel free to explain what I am misunderstanding as I love to learn anything new...

 

Good luck, have fun, and remember - you will probably also wreck this one in the snow. It comes with summer performance tyres as standard, and they don't work well near freezing.

 

Totally wrong.

The bearings are the SAME as the 93-95 engine bearings. The shaft is also exactly the same, except the rear main journal has a VERY MINUTE taper on one end...which is basically so small as to be meaningless. This is why you can sub the rx8 shaft into rx7 engines using rx7 rotors/gears/bearings with no mods if you want...because it is identical in fitment and clearance, as are all the 13b rotary bearings.

So with respect to the oil, the clearances are identical and did not change one way or another. The reason they specified thin oil was to try and improve emissions and mpg by that last 1%.

The only clearance that really changed in the renesis is the side seal-to-corner seal clearance, which is WAY looser. To give you an idea, spec for all the rx7 engines is 2-8 thousandths, while the renesis runs anywhere from 4-20. All the other seal clearances remained the same...the renesis uses the same apex seal springs and the same corner seal springs as the earlier engines as well.

You're describing the "weak compression" failure, where the apex seals wear down, the engine still runs okay but has slight power loss and struggles to idle. I'm describing the more catastrophic failure of main bearings and shafts due to thin oil. I have an engine here right now that was brought to me with 80k and every bearing in it, plus the shaft, is destroyed.

The main bearings in renesis engines are getting worn ten times as much as they ever did in any of the hundreds of rx7 engines I've torn down. The bearing is the same. The shaft clearance is the same. What changed? The oil rating.

Mazda has never built the rotary to it's fullest potential...performance wise OR reliability wise. Mazda has a tendency to design a car and an engine 90% awesome, and then f&*( up the last 10% so badly as to negate a lot of their brilliant design. When mazda designs this engine, they must take into account cost, NVH, reliability, performance, safety and emission requirements. The sacrifice some (performance, reliability) for others (emissions, NVH). They sacrifice some reliability due to cost (for instance, they know that certain coatings and materials perform better and last longer, but they cannot sell a $35k rx8 with ceramic seals so they compromise and give us what we have).

They sacrificed the proper lubrication of the apex seals via the OMP, in order to get the engine to pass the hydrocarbon emissions test...because burning the proper amount of oil means that the engine would automatically fail. Since this engine "needs all the help it can get" with respect to emissions, they also put in the thinnest oil that is readily available because that helps with cold start emissions and with mpg....thicker oil protects better but increases parasitic drag.

So yes, mazda knows things that I and other rotary builders and enthusiasts do not. But they are also limited in their ability to use that knowledge for street cars. Comparing their success in the race program to the car you buy at the dealer is highly naive. IF the race teams had their way, we'd all be driving around in catless premixed rotaries with larger ports and higher redlines, stiffer suspensions and R tires.

 

ok that clears that up. . n your're pretty much saying not to turbo the rx-8 because it'll fail eventually. . then how would u turbocharge it correctly. if you believe there is a way to do it correctly. . . the only thing i miss about the mustang is the 302lbs of torque! thats why i want a turbo! 140-160lbs is not enough lol though i did have it break loose on me today after redlining 1 and slamming into 2nd! yay, torque excites me! 200lbs of torque in the rx-8 would be about perfect for my driving style. .

 

turbo success =
sufficient cooling upgrades
oiling upgrades
proper tune (MM/Jeff)
good ignition
water/alcohol injection
and all that would be a waste without intake/exhaust chi

actually there is a whole thread about making your turbo last
https://www.rx8club.com/series-i-major-horsepower-upgrades-93/how-make-your-renesis-turbo-sc-engine-last-187240/

 

Thanks Resurrection for the clarifcation

The Renesis (correct me by any means, lol) exhaust ports already run very hot so it's hard to turbo the RX8, but anything can be done with a proper tune

 

Joker, I think that by now you've gotten a good feel for Spin9k's comment about dis-information and good information. Only way to deal with that is to spend enough time here to get a feel for who's who.

On oil weight... Attached is a scan from the Australia/New Zealand owner's manual. (Thanks, ASH8, for the original post.) This should give you something concrete to work from.

IMHO, the RX-8 should be listed as a controlled substance...welcome, fellow addict.

Ken

 

Welcome, your going to have a blast with the car. You've already got the idea of searching it sounds like, which is good. There is a wealth of information on here and some very knowledgeable members, and unlike some other forums I've been on flame wars seem to be kept more to a minimum as well.

My piece of advice to you is to plan out your mods; read, do some math, seek outside sources and look at all the options. There are all kinds of things out there for the car, not all good and some may suit your needs better then others. Either way, if you take your time and build it one piece at a time you'll have a better chance to feel your investment. Plus I feel like it fosters a deeper attachment to the car, but maybe that's just me.

 

So after reading everything and looking at the kiwi recommendations, since I live in South Florida (temp > 30F), I can run pure 30 or 40 grade oil. My gut feeling is that 5w-20 is too thin for the hot days we have. I could always have the oil changed back to stock if I take it in to the dealer! The way I drive, I don't / can't get good fuel economy. Thanks for the info!

 

Personally, I'd still use a multi-grade oil. Even if it's not below 30 degrees I like the idea of the oil being thin and flowing when the car is cold. Straight weight oil in a modern car is just a bit too Tom McCahill.

Ken