foild

do i need to collect into one pipe?
the guy @ the exhaust store is telling me i will have no low end power @ all if i run 2 straigth pipes back!
help.. my appointment is tomorow... and i need to know what to do?
RB dual header - collect into one pipe back to muffler
or RB dual header - 2 straight pipes.. to muffler

HELp!!!!

SirCygnus

iTrader: (1)

i think now is the time to say yes, make two pipes from the beginning all the way to the back.

foild

hes saying something about the pulses and ****...
im very concerned...

koukifc3s

iTrader: (3)

make 2 pipes, true dual yields more power in a rotary
n/as have no low end anyway

foild

what size?
and what about this scavenging thing?
why would he say i need this... ?

Fire85GSLSE

iTrader: (29)

I have a s4 13b na motor in a GSL-SE running the RB streetport road/race dual header into dual primaries and into a dual RB muffler.

It runs awesome.
No emissions stuff at all on this baby.

foild

but that goes into one pipe @ the end!
**** now im really confused...
please help guys time is tickin
(i may be stressin... but ack!)

1987RX7guy

iTrader: (3)

******* avatar stealer! bizitch!


True duals all the way. 2.25-2.5" pipes.

scheistermeister

damn, that confused me... took me a second to relize the other one was someone else.

Makenzie71

It looks like it collects but that particular muffler is dual'ed out inside. It's not exactly a true-dual but it's pretty effective.

Running a true dual setup will no hurt your low end torque. The long *** runners are actually pretty good for lowend torque...but "low end torque" doesn't start until about 4k rpm on the 13b anyways so it doesn't matter. The part that's important that true duals will really shine up is the top end of the scale.

Don't listen to you mechanic of muffler shop know-it-all. All other things being equal, a true dual setup will ALWAYS put more power to the ground than any other setup.

Feel free to PM me any exhaust questions. I also make and sell a true dual exhaust, as well as many other exhaust accessories...feel free to inquire about that as well.

Makenzie71

Those are WAY too big on a stock-port 13b. All else stock, stick with 2" runners.

foild

so... rb dual header.. (2)custom 2 inch piping all the way back to mufflers will work good on a stock port 86 GXL NA (thats 2 custon 2" pipes all the way back....)

Makenzie71

All else is stock? Yes, 2" runners ffrom the ports to the rear will be good.

BlaCkPlaGUE

Hey, as long as you have your ports and they are functional, the dual exhaust will not make that much of a difference in low end torque. Don't worry about it, for the high RPM performance and still very good low end torque it'll be sweet.

RXciting

i found that torque was increased in the lower RPM's after adding the true duals..

2 2" back

foild

thanks alot guys... youve boosted my confidencE!
lol wtf should i say to this mechanic?
lol

koukifc3s

iTrader: (3)

its a rotary...

Makenzie71

you should say: nothing. Buy my exhaust, or one straight from RB, and install it yourself. It's easy stuff.

foild

weird thing is.. they "specialize" in rotary's here in town

wtf is he talking about "exhaust pulses" ?

Makenzie71

General rule of thumb is to not take the car to anyone who claims to specialize in RX7's unless they deal ONLY with RX-7's.

Actually...general rule of thumb is to not take the car to anyone.

Makenzie71

every internal combustion engine (do turbines count as ICE's?) emits the exhaust in pulses. The valve opens (rotor passes port in 13b), exhaust leans, valve closes, valve opens, exhaust leaves, valve closes...etc...

totallimmortal

since there are only two rotors each pipe will be unnafected by pulses since they don't cross, pulses are the reason for equal lenth headers, but since the pipes will never touch it doesn't apply