So, I wanna build a motor. I wanna get an S5 motor thats been blown. Get new rotor housings, and send them down pineapple's way to get ported, Then have the motor rebuilt.

My question is, which rotors are better, S4s or S5s? From what I thought the S5's were lighter, better, faster.

This is for racing applications.

 

get some renesis rotors!

 

why?

 

Because they are higher compression and even lighter...
although they make no noticeable gains and require extra machining to go them to handle peripheral exhaust.

Waste of money.

Turbo use S4 rotors because they are lower compression.
N/A use S5 rotors because they are lighter and higher compression.

But RX8 Eshaft is lighter then stock and a direct replacement.

 

haha, so you think for a ported turbo set up, S5 motor, S4 rotors, RX-8 E-Shaft? What about all the gaskets and bearings? And as far as the apex seals are concerned, what is the biggest bang for my buck?

 

The internal setup relies heavily on what type of racing your doing? AutoX i would say S5 turbo rotors for a little less lag. But if its all out drag racing the few more pounds of boost you can use with the lower compression s4 rotors might help on the top. But for most motors its rx8 E shaft unless your gonna get stupid. then put up the$$$ for a Guru 2 piece shaft

 

is this a turbo or n/a build?

 

the RE is best for building a turbo. It doesnt have the weak area on the rear plate and it has better a better upper intake manifold

 

i believe a S4 rotor are iron casted therefore can take more abuse than a S5. I'd say go with the S4's but it depends on what your rebulilding N/A or Tubro?

 

pretty sure S6 is the first series that were machined.