Hi all,

Does anyone have definative answers on the differences between the engines? In the UK the RX-8 is only available in Manual but you can get the low power 4 port or the high power 6 port engine, in Australia you can only get a 6 port high power manual or a 4 port low power auto, (not sure about the US?) based on this I thought I would list some queries below:


1. Are the rotors or any other block components different between the 4 and 6 port engines? (I know the end housings are different being 4 and 6 port) but are the rotors the same weight, gearing, and compression?

2. Rev limit is lower for the 4 port - is this because they don't make as much power up top? I think the 6 port has a 9400rpm limiter? what about the 4port?

3. Do both engines work off a crank angle sensor like the FD engine?

4. I know that the inlet manifold is different for the 6 port - i.e. I am assuming there are two completely different intake manifolds for both engines?

5. Fuel systems different between the two?

6. Any differences in the ECU's?

7. I believe it is a fly-by-wire accelerator?

8. Anyone know injector sizes and flow rates?

Be great if some of these questions could be answered by the guru's out there.

1. Are the rotors or any other block components different between the 4 and 6 port engines? (I know the end housings are different being 4 and 6 port) but are the rotors the same weight, gearing, and compression?

Rotors and blocks are the same I think, but the low power doesnt have the ectra ports etc cut or the support hardware.

2. Rev limit is lower for the 4 port - is this because they don't make as much power up top? I think the 6 port has a 9400rpm limiter? what about the 4port?

REv limiter is lower because it doesnt have the extra ports. The exrta ports are what allows the engine to breath enough to rev higher. That and the other hardware (3rd injector etc).

3. Do both engines work off a crank angle sensor like the FD engine?
No idea.

4. I know that the inlet manifold is different for the 6 port - i.e. I am assuming there are two completely different intake manifolds for both engines?

Yes. The Hi-power has an N-DIAS air intake system utilizing hermholtz tuning etc. theres the ettra ports and variable resonance air intake etc.

5. Fuel systems different between the two?

Yes, the hi-power has an extra fuel injector.

6. Any differences in the ECU's?
I doubt theres any physical difference, but will be running different code.

7. I believe it is a fly-by-wire accelerator?
Yes.

8. Anyone know injector sizes and flow rates?

I think they were posted, and the high power injectors have adequate headroom for a decent mount of modding.


Dont get the though of turning the lo-power car into a hi-power car, it wont happen, and as there is only £2k difference (for which you get a 6speed gearbox, Xenon headlights and alloy pedal set) why would you want to, it will certainly cost you more than the difference.

As to adding more HP, if done via a turbo it seems the 4 port version is just as good to turbo as the 6 port.

Hi Rob,

Thanks for your responses.

You may have read my other post - yes I decided to go with the 4 port engine as I was worried about the port sizes on the 6 port - and the basics of getting the inlet manifold sorted for forced induction. And I wanted the auto - god knows how strong it is going to be?

Would be aiming for 350-400 fwhp which should be quite achievable.

.ps Do you know of anyone that has successfully turbo'd or supercharged a renesis engine as yet?

Where do you live? There is no Auto in the UK, probably wont be, you Australian?

The Renesis is already a high compression engine (10:1) so speculation is that you are best using a low boost turbo only (without internal engine modification?).

Have a look at threads like this :
http://www.rx8club.com/showthread.php?s=&threadid=15362

No one has officialy (in UK/US/AUS) released a turbo or charger yet, but there are many working on it.

Thanks Rob - yes in Oz at he mo. but will be heading back to the UK next year.

cheers for the link.