NatAsp12A

So I plan on getting RB Headers and I'm not sure what to do for an exhaust. Keep the cat and delete the muffler, delete the cat and keep the muffler, or just do a full 2 or 3 in straight pipe all the way? State doesn't care about emissions, just don't want to get pulled over for a loud exhaust.

Qingdao

iTrader: (3)

The RB duel exhaust is the way to go. Well it collects at the muffler but it's pretty much duel. $1k and you'll never have to muck with your exhaust, and sounds great.
Except if you go turbo.

ray green

iTrader: (14)

RB all the way is what I say.

Smooth and purrs like a kitten.

NatAsp12A

Ive been thinking about a high flow cat then maybe a 3 or 4 inch pipe all the way back.

eprx799

iTrader: (8)

I have a racing eat exhaust on my street/track car and it's great probably 8 years old already still sounds and looks good. I had 3" custom stainless exhaust on my race car with a Burns Stainless muffler on it was supposed to be 90 DB compliant, and it would split your ear drums you could hear the car all the way around the race track. You won't get away with just a muffler or just a cat on the street.

peejay

Buy the Racing Beat exhaust.

Only put a 3 or 4 inch exhaust on the car (really?) if you plan on never driving it.

Believe it or not I found minimal gains from going to a 2.5" exhuast from the factory 1 7/8" midpipe, on a ~210hp street ported 13B. Highway drone increased dramatically until I put a 1.75" restrictor in the exhaust tip, which did not hurt power at all (A-B-A testing at dragstrip) but did cut down the drone substantially.

Then I got a RB exhaust and wondered why I wasted so much time and money in trying to do it myself.

lastphaseofthis

iTrader: (8)

dis my 3 inch, i dunno.. no drone. maybe turbo helps with that.


fc but still ..

fb will get 3inch turbo back as well. but dual exit one side. like stock.

peejay

You also have really shitty restrictive mufflers, too. N/A rotaries don't tolerate baffled mufflers, and baffled mufflers don't tolerate N/A rotaries.

RB systems are straight through.

lastphaseofthis

iTrader: (8)

oh hush, this one is not n/a... nor be the FB. a baffled exhaust is the only pleasent rotary i've heard.. arent the racing beat baffled???
why you trying give everybody p port resticiveless exhuast he said he didn't wanna get pulled over.

also even tho they are baffled, they are also 3 inch, in and out, times two...guess i will need data.. via emap.

peejay

The RB mufflers are straight through. No baffles. They are VERY quiet.

When I went from two 2.5" perf-core mufflers (no baffles, no louvers) to the RB long primary exhaust, my backpressure went from 4psi to about 1psi. Noise also went down dramatically. I couldn't hear the engine anymore over the trans and diff whine!


(this with the half bridge GSL-SE engine)

Part of the reason they are so quiet is the thickness of material used. It kills the sound transfering through the pipes. All exhaust sound goes out the tailpipe, none broadcasts from the pipe walls.

The exhausts are also HEAVY because they have large chambers filled with stainless steel mesh/shavings/etc.

NatAsp12A

So if I didn't have enough money and wanted to make my own bolt up exhaust, would that work? Like a straight 2" from the downpipe to a high flow cat, then after that a 2.5" or a 3" to the aftermarket muffler?

WANKfactor

iTrader: (1)

^ Yeah. Try and do a copy of the rb. As everyone has said, its tried and true and the template for na rotaries since adam was a boy. Primaries merging before the diff. Length of primaries having an effect of power delivery. Thick wall pipe. (mild steel is fine) heavy straight through mufflers and resonators, as big as you can fit under the car if you want quiet. Dont go stupid big on pipe diametre - it will most likely hurt performance and sound stupid.
A couple ideas for brain food - perforated tube apparently flows better than plain pipe. An exhaust can taper down slightly from front to back to maintain gas velocity as hot exhaust gasses cool and shrink.

NatAsp12A

I want it to sound louder and just get rid of the resonator so I can have random backfires and so it can breathe easier. Not really looking for a huge performance gain or a major loss in mileage.

Qingdao

iTrader: (3)

RB is the only bolt up exhaust for this car.

You're gonna have to learn to weld, or have a hideous amalgamation of u-bolts holding pre-bent tubing together.


Not saying you can't do it with u-bolts (**** I use a slip joint on my red car's exhaust between the mid pipe and the hump). I'm just saying the moment you peek under there your gonna think EWWW.


My first car I used a glass pak and a flowmaster with some 2" pipe. It was loud... louder when all of the packing came out of the glass pak, and in retrospect it would have been cooler to get a real exhaust like RB. Although, before that exhaust I had no exhaust so it beat open header.


EDIT: I wouldn't put a cat in the piping. They tend to clog and muck up without the air pump.

NatAsp12A

My brother welded his straight pipe for his truck until it rusted off due to salt (don't worry, I won't drive the rx7 in the winter unless I absolutely have to, then I'd make sure to spray it off from top to bottom) anyways I could have him weld up the exhaust once I buy everything, and if I buy a universal bolt on high flow cat, wouldn't that work? I just want a cat on there so if any reason I get pulled over I won't get a huge fine for not having a cat on there.

WANKfactor

iTrader: (1)

you could just U-joint a nice 2nd hand straight through muffler on - it will definitely be louder. Or just get your bro or the local exhaust shop to try and replicate the RB set up using good quality, SS packed mufflers and reso's. Take my word for it though - once you get rid of the std wxhaust it will be loud. Its always an uphill battle keeping them quiet without going bafled or chambered mufflers which rotaries hate.
I don't know how the rb exhaust is so quiet in the vid peeyay so kindly put up - although i bet it sounds real nice outside the car or when the windows are rolled down. I'd love to know the specs on those.

Qingdao

iTrader: (3)

catalytic converters need a leaner environment than the exhaust of a rotary to operate properly. If you put a cat on you need the smog pump.

If you really care get a second hand cat and hollow it out then stick it under there.

cshaw07

iTrader: (14)

i'm going to run an rb 2-1 header, into 2.5" .120" wall tube to a long glass pack with the glass removed and replaced with steel matting, to 2.5" over the axle into a 2.5" magnaflow with a pie cut turn down tip. No idea how loud it will be.

peejay

That isn't entirely accurate. I passed smog with a free breathing check valve mounted in the ACV block off plate. No air pump or solenoid rack. The vacuum of exhaust pulses drew air into the exhaust. Some OEMs did air injection this way (like my B12 Sentra did)

Cat lasted forty miles though!