Anyone have any guess on how long the Apex seals will last on the new NA 13b for the RX8?

Im still learning about this engine and any help would be appreciated!

 

Not long !!! Way to high of a compression ratio for a detonation prone engine to begin with!!!! Something like 11 or 12:1!! Maybe higher. (That's what i hear anyway. haven't seen the FSM yet.)

 

I think the compression ratio is 10:1 but i could be wrong.

Thanks for the response tho its something to think about.

 

Either way it doesn't leave much room for improvement..(I.E. turbos, supercharger, etc...) Maybe we'll see the second demise of Mazda due to bad engineering! ( first time was the first gen. mazda was going bank rupt and was calling it quits when ford stepped in and saved their asses. Amazing what a lttle R&D $$$ will do !!!) Only time will tell. The first time the engines went pop! around 20k miles....We'll see. I did see on here that someone in New Jersey I believe has junked the renesis for the turbocharged 20B!!!! Now thats an engine improvement!!!

 

Thanks for the responses! I wanted to get contrasting opnions from you all here at the motherland and from our RX8 forums to get the best of both worlds.

So far both opnions contrast greatly but its ok i have some good info from both groups. Like you said, "i guess only time will tell!"

Ill stop beating a dead horse hehe thanks agian for the info! You guys are really cool to us new to rotaries and if i find anything new ill be sure to post em up!

 

Renesis has 10:1 compression

 

renesis has 10:1 compression. the new apex seals are 2mm X 8.5 mm X 80mm and are 2 piece like the old pre-1986 seals. this design is stronger. lets not get all negative about the engine, yet.

 

With the side exhaust ports of the renesis. The carbon and debris hovering around a peripheral exhaust port is eliminated. No more devils marks (scoring of rotor housing around a peripheral exhaust port). Also, the apex seal is now constantly riding the peripheral housing providing support for the apex seal and also reducing the chances of the seal being chucked out the exhaust port. The apex does not have to pass through the exhaust port (an unsupported and weak area). Much more reliable IMO.

 

Rotaries are not detonation prone. In fact, the high turbulence in the combustion chamber makes them very detonation *resistant*.

If you manage to get a rotary to detonate despite its natural advantage, however, it's more than likely going to be big enough to do damage, which is why people are so paranoid about detonation. One way to overcome the advantage is to cram a bunch of air into the engine via a turbo, and if you've noticed, RX-8s do not have turbos...

 

The decreased seal "flutter" due to the lack of a peripheral exhaust port will extend seal life. At any rate, they'll last longer than a 2nd gen NA would. I hear they improved the oil-injection system; can anyone confirm this?

 

I'm pretty sure they did.

 

There are now 2 oil injectors on the housings per rotor

Rotarys are far from detonation prone as peejay said.

The seals are now 2 piece and a hair under 2mm thick ( like 1.956 or something), and since they no longer have the tiney 3rd piece at ther tip to wear down over time and eventually break, they should surpass current NA rotarys in mileage(300,000k+)

Also 10:1 is only .3 more then the 89+ rotors, so its not that big of a differance, and people have still turbo's the 9.7:1's

 

much of the info passing here is true. I have driven 4 rx-8s and i have mixed reactions about there performance. The horsepower figures are definently low. Car feels very rigid, nice suspension. Motor feels fairly flat unless you really buzz it. Whoever said the performance is maximized is totally wrong, im curious to see what a flowing exhaust would do to these things. The whole exhaust is one restriction after another with a muffler at the end as big as me curled in a ball. Once again we come back to the FDs demise apparently due to higher emmisions standards.\
As stated ealier, apex seals are just under 2mm 2 peice design. Oiling system is upgraded. GEOMETRY REMAINS THE SAME. Interchangeable parts yet to be determined, apparently guys in japan modifying rotors to fit previous rotories, preticulars im not sure of. Lifetime expectency in my opinon is very dependent on the owner. A well maintained vehicle which is driven as a daily driver will last at least 200km +. If buzzed and buzzed often, I could see excessive wear on the tops and bottoms of the housings, a characteristic of rotories exceeding 8500rpms. The only way mazda may have may have tackled this issue is related to the metalurgy of the rotor housings suface.
Whoever said rotories are detonation prone more than likely does not understand what detonation is, by defintion, nor how the rotary works. As with all forced induction applications, detonation can occur, piston or otherwise. 10:1 (as in the renesis) will not be detonation prone in my opinion.
All things point to a more reliable motor, EXCEPT the raising of the power band. This is all my opinion, I work for mazda but I dont go to rx-8 triaing until oct. Ill keep ya posted.