So I'm researching and piecing together parts for the inevitable rebuild... I'm going from 3mm steel seals to 2mm ceramic ones, so I'll need rotors.

I heard that the 13b rotors have different weight ratings, "A" through "D". I also hear you don't want to to mix 2 rotors that are off by more than one letter.

What is the difference between these ratings? Which is heavier?

Also, I've heard of people using RX8 rotors. Is this a good idea? What differences do they have and what modifications are needed to use them?

Thanks!

 

You are correct about mixing rotor weights, however you can get your rotating assembly balanced and that is no longer an issue. If you are going for low weight then pretty much the newer the rotors the less they weigh.
old school 13b > S4 > S5 = REW > RX8
and by > I I mean heavier than


RX8 rotors have a beveled edge which gets you a slightly advanced opening timing. I personally dont really care for the new side seals or shallow apex seals. There arent really any modifications needed to run them, but I would get the rotating assembly balanced if you do.

 

Hmm OK.

Well I have a friend who has a matched pair for sale that have a rating of "D".. Would that be newer/lighter or older/heavier? What does REW stand for?

Thanks!

 

You would need to know what the rotors were out of. The difference between A B C, etc isnt going to be enough to make a responsiveness difference, its just balancing and you cant tell the engine the rotors came out of based on the letter.

REW is the FD twin turbo motor. Does he not know what motor the rotors came out of? You need to be sure they are indeed the same, as you wouldnt want a S4 rotor stamped with a D to be mixed with an S5 D rotor. Both weights and compression ratios would be different. Same with NA vs. Turbo, they are going to have different compression even for the same year of motor.

Maybe you can take them to a shop with a gram scale so you can at least know for sure the weights are close.

 

Oh they came from the same motor.

Thanks for the info!

 

so yi dis ne....

 

i love this club more!!

 

I was under the impression that the RX-8 apex seals don't tolerate peripheral exhaust ports.

 

They are shorter top to bottom, so they will certainly flex more and life will be reduced because of it. I dont know how significant but I wouldnt personally run them, and I especially wouldnt run them if the exhaust ports were enlarged beyond anything stock. In my mind there is no good reason to run an RX8 rotor in non-renesis motor.

 

They are SIGNIFiCANTLY cheaper, how's that for a reason?

 

Thats not really a good enough reason to me, you can find good used rotors for cheaper than new renesis. But this is all personal preference.

 

What about the boost in compression with Renesis rotors? Isn't that a benefit?