just a couple quick questions on real dual setups:
1-should i use a H or X pipe section?
2-will putting the factory 02 sensor in one pipe in the header make readings good enough for the 02 sensor?
3- what dia. of pipe is used for the header section (i think 1 7/8")
thanks in advance

 

1. i'd do neither if you want true dual. you'd have to know how to tune exhausts. but if you chose either of the 2, i'd go with X.
2.yes
3.On my setup it's 2.5in all the way back from the engine. header included.

Matt

 

i believe that the O2 sensor would have to go in the collector part of the pipe, yes?

 

thanks marlaman, i like sound of 2.5" the bigger the better, especially when i consider my factory type setup uses a single 2.5" section from the manifold to the Y

 

doesn't HAVE to i don't think... your ecu should be able to compute the a/f via one rotor, and provided your rotors are running equally, you will have no problems.

 

You can't have a true dual H or X pipe.. or at least that's how it is to my knowledge

True dual means the 2 banks on a V configuration engine's exhaust (or in this case 2 rotors) never collect or meet

?
I think the one i have from mazdatrix.com is a twin 2-2.5" front to back

Frank

 

I like the mazdatrix setup. But I'm also intrigued by the RB.
But to answer the questions.
1. No X or H, either Y or true seperate duals from header back.
2. Yes
3. 2.5" Bigger the better.

But I have a question of my own. Is there such a thing as too big on a 7? In my opinion the rotary responds better and better the bigger the piping.

Rabbit

 

Bigger the better on an N/A is not true

a tuned exhaust is made so that at a certain RPM the exhaust gases flowing through it maintain momentum between exhaust pulses thus creating a scavanging effect when the next exhaust pulse comes around.

if the exhaust is too restricive then that momentum/scavenging effect is reached at too low RPM's or not reached at all and cause backpressure at higher RPM's

If the exhaust is too large then the exhaust gases will not be able to get sufficient momentum and also cause another problem when the next pulse comes out since it's gonna hit air that's just stanting still and have to move that out of it's way

also exhaust and intake have to almost be tuned together.. but i guess that's another story.. BUT!, too large of an exhaust will not be beneficial to a stock intake manifold

 

Will 3.15" true duals be fine on a port+polished intake manifold?

 

exactly, it isnt a "true" dual unless they are seperated the whole way back.

ya you can have too big of pipes on any car...

 

i'm thinking anything over 2.5 dual for an N/A is just too damn big

maybe if you had a P-Port but i still think a 2.5 dual would be suffiecient

Frank

 

No, neither... will drop torque if you do
yes
2" is perfect... do not go any larger than 2.5" or you will loose considerable exhaust volocity.