So its been said that the stock Rx8 apex seals bow/wear fast when used with PP exhaust. But, after A LOT of searchng here, among other sites. I can't find no "real world" documentation to prove it. If someone has actual information on why they cannot be used, please infor me. NOT speculation and theory please.

Esmeril Racing (ChrisRX8PR) has designed a very nice set of seals to fit the renesis rotors. They have seen abuse and high boost for a few years now in the renesis motor. What is unknown is if they can handle PP intake/exhaust motors. Given there higher strength and different material, im wondering if they will work in a PP intake/exhaust motor. This would be a easier, and much more affordable option to machining, balancing, and using older style apex seals and corner seals.

A pm from ChrisRX8PR:

"From the design phase of our seals I can tell you that they are superior to the OEM ones. People revving N/A engines to high rpms using RX-8 rotors in older peripheral port housings have "said" they experienced slight bowing of the seals with time but no one has documented this in real life, after much research is sounds like speculation, not testing. I will however add that our seals are better than OEM and this might not be the case. I will also add that I know if one Renesis engine with Peripheral intake ports machined into the housings that has flown for many continuous hours in an airplane without bowing of the OEM seals. Being that our seals are superior I wouldn't expect them to bow over the exhaust port. My guess is that it is a factor of EGT's. Keep the engine in its sweet spot so the EGT's don't go through the roof and you should be fine."

 

mazdatrix built a peri exhaust port engine, had poor results and posted em up on here, or maybe it was the rx8 forum.

mazdatrix also is involved with the airplane engine, http://www.rotaryeng.net/
that one is peri INTAKE, which might matter, as the intake is much colder than the exhaust.

 

Dave Lemon posted that they built an engine, and it lasted at least long enough to be broken in and a couple dyno pulls made, but there was no followup post. This was in 2003.

 

since people tend to say that because of the short height they can't handle the heat my question is, are the renesis seals' height much shorter than the top piece of oem FD 3-pc seals?

 

That is exactly my thoughts! I was waiting for someone to mention this.

 

am testing one in a few weeks, ill post results...building the engine now. PP RX8 COMPLETE BALANCE ASSY AND 2 GEN HOUSINGS.

 

cool. you'll be using stock Rx8 seals or the Esmeril racing ones?

 

stock apex seals!

 

sweet. i think they will hold up just fine!

 

If you can keep your fuel delivery and egt's under control all Apex Seals should survive an N/A setup. Heat and detonation is what kills Apex Seals. There is one other thing I have seen people fail to mention when they discuss mixing and matching engine parts. If you grab a couple of sets of rotor housings from different years you can see the phyiscal differences in the various rotor housings sold from 1978 thru 2009. The newer rotor housings have much tighter clearance to the apex seals compared to the older style housings. My recommendation would be to use the latest model rotor housings available for your project because the tighter clearances will result in better compression.
This is just my opinion from what I have observed on my own engine setup/combination.

 

What about using ceramic seals?