Hi,Iv been reading about the CLR rotors and the chamfered edges in the Renesis rotors and how the Renesis rotors have a 10:1 compression compared to the Fc's 9.7:1 compression ratio.I am trying to make as much power as possible with out going turbo.Since the CLR rotors are kind on the $$$ side,will the Renesis rotors fit right into the s4 housings?Also,this is kind of a stupid question,but what is the compression ratio comparing?The air to fuel ratio?Thanks in advance!

 

I know there are a few threads around here about them, sorry I do not have any links. But if I recall, they fit fine othere than some seal groove needs machined to accept teh earlier seals (maybe apex seals).

As for power, I just know from a street ported/built engine making approx 220hp will put down 15-20 more, again there is a thread on this somewhere.

 

compression ratio = compressed volume to uncompressed volume. Bascly when the air gets compressed, it's ratio between before compression begins to the part of the rotation when the rotar is closest to the housing. A higher compression ratio generally means higher hp because you are sqeezing more air into a smaller space.
I've wondered about putting RX8 rotars into my Fc too, not too much info on it from what I have seen. You might have to order one to see if it fits. It would probably be possible to compare the stationary gears from the RX8 to the FC; that would tell you alot.

 

[QUOTE=C-Murder] A higher compression ratio generally means higher hp because you are sqeezing more air into a smaller space.
QUOTE]
Actually your squeezing the same amount of air tighter, which means higher combustion chamber pressures, therefore torque and horsepower.

 

There's a site that did it, I think mazdatrix, might try shooting them an e-mail?

 

th epower diffrence between the rx8 rotors and the s5 9.7:1 will not be big. it woudlnt be practical just doign the swap fo rthat reason. rx8 rotors are lighter but a good amount, and you could rev them higher and port the motor bigger to take advantage of that. but to fit the rx8 rotors into the earlier engines you need to machine the apex seal groove deeper to fit the older style apex seals as you will need them due to the peripheral exhaust port you will be running. you will also need to get the frotn and rear counterweights to have the assembly in proper balance. like i said if you are doing the swap only for teh sake of compression it snot worth it. if you are planning to port teh motor big and rev it high then the rx8 rotors are to be of more advantage then lightening the old ones as the rx8 rotors are a cheaper option and you get the little bit higher compression also.

 

I believe Banzaitoyota actually dynoed an engine with Renesis rotors and disassembled the engine to compare with S5 rotors. He said that he achieve 8hp extra with the Renesis rotors.

For all but 3 people on this forum the cost and effort aren't worth the gains. If you're talking about a street engine and you're willing to pay for that extra 8hp, it's time to look at a turbo.

 

wheres the thread on these rotor swaps?

 

It's not worth the hassle. Sure there are gains but the cost involve to get a MSP rotor to work in DEI engines are just not worth it.

For the cost of getting it done (all the cutting, and of course u need a pair of them) it's actually cheaper to just get a pair of lighten Rotor sets and start from there.