i was looking at numbers for the S4 and S5 RX-7's and i noticed that the S5 makes more horsepower and torque at lower RPMs.. how exactly do they make that extra power? i read something about VDI, but i thought that VDI kicked in at higher RPMs, but the S5 makes more power at low RPMS, so that doesnt seem like thats what it is. so what creates that extra power?

 

The intake manifold is designed better. Air flows much better than s4 manifolds. Also they have lighter rotors and they redline higher than s4. Im not too sure but I think the compression ratio is higher too.

 

S4 block can handle more boost than s5 block!

 

Can an S5 intake manifold be transfered to an S4 without any headaches?

 

I believe someone has done this and Yes I think it is quite possible. I would either wait for confromation cause I already have an S5 and have no need to do that; or go look through the results of a search. I do remember someone posting this maybe a week ago, give or take. Good luck. And the blocks with boost? I don't know if that is completely right. I think a well tuned car can take as much boost as any other well tuned car. So I am thinking blocks woldn't matter. However I can't spell right today so I wouldn't expect anyone to think I know anything about a turbo cause mainly I don't have one. It's the way to be if it's turbo free.

 

Not quite true there mate,

Series 4 rotor can handle more boost because they are a lower compression ratio, therefore with the same octane fuel you can run more boost in a motor with series 4 rotors than you can in a motor with series 5 ones.