im assuming that you are gunna use brand new renesis rotors? usually people mill and replace with larger seals when their old rotors cannot accept the 2mm seals. if you're gunna detonate, 4mm seals will break just like 2mm seals would, maybe it will last a tiny bit longer but not by much



(someone correct me if im wrong)

 

S4 NA was 9.4:1, S5 N/A was 9.7:1, RE is 10:1.

S4 Turbo was 8.5:1, S5 TII and FD were 9.0:1



There were no factory rotaries with a compression higher the 9.0:1.

 

they may not stand up to detonation any more, but they will handle the extra combustion chamber pressure better. And it ends up that I'm stuck with 3mm seals with the renisis rotors, not enough material to go bigger, but thats still improovement over the 1.5mm stock ones.





Its unfortunately true. And like I said earlier, I'm stuck with 3mm for that exact reason.

Someone please invent apex seals that seat deeper into the rotor!!!!!!

 

3mm in Renesis? 1.5mm in stock??? There aren't any 1.5mm apex seals; they're all 2mm. I believe the Renesis uses 2mm as well.



Combustion chamber pressures, under normal combustion even at very high loads, won't compromise the factory apex seal, let alone any of these 2mm 2-piece designs that are available from a bunch of different places.



You'll be just fine with 2mm.



B

 

I believe the rx8 does have 1.5mm seals. I have heard it more than once. If I'll be just fine with 2mm seals then why do people even use 3mm seals at all? slots too worn to hold the 2mm any more? Hmmm, I do know that all of the past rotaries used 2mm 3 peice seals stock, and that atkins offers 2 different types of 2mm seals, one with a longer corner peice than the other, what are the advantages/disadvantages of the two?

 

The RX-8 uses 2mm seals with less depth.



Not all rotaries ran 2mm. The switch came in 1986, when mazde went from the First gen 2-piece 3mm seals to the 3-piece 2mm apex seals used from 1986-2002. Some of Mazda's earliest apex seals were 6mm carbon apex seals; absolutely huge!



People use 3mm seals for two reasons: when their existing rotor apex seal grooves are too worn to accept stock seals, and when their tuner needs the extra edge that the extra width gives them against detonation. The 2mm seals seal better and have less mass for high-rpm use.



If your tuner needs 3mm seals, then you should find a better tuner. The stock mazda apex seals have been proven above 700hp; combustion pressure is not a problem.

 

on the rx8 tranny talk to judge ito he's had some problems............

 

if you rotor is not fucked to use 2mm then i wouldnt go with 3mm, they cause more wear and are heavy. there are plenty of cars out there for you to notice that run ridiculous amount of power on stock seals which should be enouf to tell you to leave something thats well alone. ANY SEAL WILL BREAK UNDER DETONATION. if you cant tune teh car the fatter seals wont realyl help you.



i think the 3mm seals are great once you chewed up your 2mm ones and need to machine teh apex goorves this is the time to go to 3mm if you have no money to get new rotors.



the rx8 seals are same 2mm just not as DEEP as the old type of apex seals so you cant use them in the older deeper grooved rotors.

 

alright, thanks, this is the stuff i need to know. Now, can I get the rotors milled to accept deeper seals, like the atkins 2 peice, or is there any point in doing this, will the rx8 rotor fit into the s5 housings without mods?

 

the rx8 rotor will fit if you machine the groove deeper and use old seals, but i am not 100% sure on this. i am nto sure if all the other seals will fit from the old rotors. cause if not rx8 seals are very expensive and wont be worth doing this modification, there is a thread here somewhere about this