I had my FB up on the lift the other day and i was wondering:

If i was able to buy a header and cut off the end so i have 2 pipes would it be possible to run 2 pipes straight back to 2 smaller mufflers?

What would i lose by doing this, Backpressure etc, etc.....

Would it sound wierd because it would be one rotor per muffler?

Has anyone done this?????

Jay
1984 FB

 

thats how I've done my cars and friends. Ditch the flange. Two separate pipes/mufflers = TRUE DUAL EXHUAST.


LOUDDDDDDDDDDDDDDDDD

 

And you'd lose the scavenging effect of your headers.

There's a reason they are called "extractors" in other countries.

 

Dosent the RB racing exhaust have 2 pipes?

I didnt thing "scavenging" mattered to rotaries only piston engines???

Jay
1984 FB

 

The RB system collects near the muffler. Scavenging does apply to rotaries. The exhaust pulse of one rotor helps to extract the exhaust of the other. I would do a collected exhaust (either collect at the header or near the muffler). The true duals may possibly have a bit more power up top, but the rest of the range will hurt (all things being equal).

 

How about putting an X-pipe on it??

 

RB and some other folks have done very specific research on this. This is why their collected header collects at the point it does and why the streetport model collects where it does. In you look in thier tech manual they suggest, for example, that a spreetported 13B should have a total uncollected pipe length of 125" (that would be measured down one side to the collector and back up the second pipe. Hey, they have spent the time and money to figure out what works.

 

i have true duals right now. the only difference i noticed was the weak low end torque. other than that i like it.

 

Picture could be better. I'd say go for it but you'd need to relocate the fuel tank a bit to fit the pipe in

 

The FC system sold by Mazdatrix(I think its RB)....is a true dual all the way back.They claimed a 28% increase of RWHP with that system on a N/A 2nd gen.Im not sure how well that compares with a regular,collected aftermarket system,but their peak HP gains were very high up in the revs.Id guess that the collected system will boost midrange much better.Scavenging is definately a big deal on rotaries.....with their "always open" exhaust ports and strong exhaust pulses,they are a perfect candidate for a tuned exhaust system when run without a turbo.Thats why performance exhaust systems make such a difference,the stock manifolds and pipe diameters are junk!

Looks like they changed from the old heavy dual presilencers, to a dual-path single presilencer......that should cut some weight over the older design.
http://www.mazdatrix.com/r-ex86nt.htm