Exhaust System.
 

From the underside pictures taken in Geneva (http://www.rx8forum.com/showthread.php?s=&threadid=3102) it appears that despite having two exhaust pipes the RX-8 only has one silencer. So a single pipe goes to the silencer and is then split into two for cosmetic reasons? Is this correct? Also, what is the purpose of the rotor shaped red light below the rear bumper: fog lamp?

Yes it is split for cosmetic reasons. It is ok, I want a true dual anyways, There are very few, if any, companies that still sell a true dual exhaust. That just leaves extra hp for me to pick up. I think a header/full exhaust shouls net 15-20whp.

Kyle Lancaster--Double Agent Salesman

Wouldn't a full true Dual exhaust on a 2-rotor not even have a header? or am i missing something...

Lensman, rotor shaped light is a fog light.

Thanks everyone! :)

Re: Exhaust System.
 

Excuse the poor quality..but you get the idea

Well I hope it's stainless steel because it'll be expensive to replace! Thanks for the diagram.

IMHO there nothing wrong with the Mazda design. If you look at the E46 stock or aftermarket exhaust (Eisnnerr or Active Autowerks), they used the same design with no compromise.

But, on the other hand, I would like to get a Titanium exhaust to shave some weight. Stainless T304 or T321 would be nice too, but weight.

Doesn't the exhaust port in the intermediate housing join the exhaust from the two rotors? If so, there is no chance for truly dual exhausts for the two rotors.

-Max

uh, no, i don't see how that's possible, because the rotors are 60 degrees (which is 180 degrees of e-shaft rotation) out of phase with each other... wouldn't that create serious problems with pressure waves moving back and forth between the two chambers, among many other things which i don't have time to think of because i have to go to work?? :D see ya boys.

Yes! A Ti muffler will chop ~15 lbs from the tail of the car. No move the battery location to the trunk and substitute a light weight battery for the stocker and save another ~13 lbs. Weight distribution now goes from 52:48 to 51:49. Halfway to perfection.

Here is a pic of the exhaust port in the intermediate housing (the one in the middle).
http://images.rotarynews.com/images/...3/mvc01852.jpg

This makes it impossible to completely isolate the exhaust from each rotor into true duals. Wakeech, it probably wouldn't work very well if both rotors opened their exhaust ports at the same time, but I guess it is okay to share the port with them firing alternately. Many of the stock manifolds for rotaries over the years joined the pulses right outside of the engine anyway, so this probably isn't so different from that. It looks like there is a divider in the there to direct the exhaust out of the port rather than blowing on the adjacent rotor as it moves by its port.

-Max

The 52:48 figure from R&T was with driver.

The last time I checked the RX-8 needed a driver.

No you don't.
http://www.btinternet.com/~reg.joy/i...ots/johne5.jpg

Johnny 5 alive!

No disassemble number 8!

maybe it needs more input? I BETTER MASH THE GAS! HOORAY!
________
Ship sale

hmmm... well, i suppose that would work (??) otherwise the motor wouldn't run, eh?? ;)

but yes, i suppose that the divider makes it effectively ALMOST two separate ports, which i suppose is all that was needed...??

Let me make sure I understand you all. Are you trying to say that the exhaust ports for the two rotors are both in the intermediate housing?

there are two exhaust ports per rotor: one in the side housing (primary?) and one in the intermediate housing (secondary?)... it's these ones in the inter. housing that're kinda screwy...:confused:

so it has 4 exhaust ports total: 1 in the rear housing, 2 in the intermediat housing, and 1 in the front housing?

The middle plate or intermediate housing does indeed contain two exhaust ports or one on each side and they mix together before they exit into the exhaust manifold. I assume this is for scavenging. If so, this may affect in a negative way a three rotor Renesis as their rotors are phased 120º apart; the exhaust pulses wouldn't hit each other inside the port at the same interval as with a two rotor engine. This may not be a problem though. Think about the missing counterweight on a 20B eccentric shaft for a minute. Each rotor should have a counterweight, yet the 20B only has two. The middle rotor has none, unless you count the other two rotors as sort of offseting it, or something. The 20B is a smoother running engine than a two rotor even without a third counterweight. The point is that maybe it just simply won't matter-the exhaust port, as it doesn't seem to matter in the two rotor Renesis.

Also about the exhaust ports and which is primary/secondary. There is no difference. They all exit at the same time. Well, maybe the ports might open sooner in the end plates, which could possibly make them the primaries, but they're also larger than the intermediate port which serves double duty venting both rotors. Heh, this is fun.

so, are the intake ports configured the same way, or did they stay with only having one set of ports for the intake? I can't wait to take one of these engines apart. I've built a couple of the older style engines, but this new port layout is weird.

precisely why i spend so much damned time here :), and why i wanted to be a mod for this forum (Herc beat me to it *shakes fist* :p)

anyhoo, my rationale on the ports is just that the nominclature would reflect that of the intake ports: ie, if the side housing intake ports are primary, then the side housing exhaust ports too would be the primary ones.

on the intake side, i believe that the intake port layout is nearly identical to that of the Series 5 13B as far as fundemental design goes (with the tertiary or "5th+6th" valved ports), but the placement is lower down, closer to the exhaust port.

Well, the side plates actually contain both primary and secondary intake ports. On the GSL-SE engine, all three side plates flow primaries. In the case of the front and rear plates, it's just the lower ones. The secondaries are the 5th and 6th ports. All 6 port engines run this way, even the Renesis. There's no tertiary ports :( (I already checked :) )it would be cool if there were, though.

Does anybody know about the intake butterfly valve/upper intake manifold section? Aren't there three valves? Isn't it two butterflies for primaries with one per rotor and the third butterfly for the secondaries (5th and 6th ports) or something? This is what got me thinking about tertiary ports, but then I learned it doesn't have them. Anybody?