75beetle

Should or shouldnt i and if i do what kind of muffler should i use?

Thanks Alot

FirebirdSlayer666

iTrader: (3)

Well straight piping means no mufflers, which I wouldn't recommend unless you have a mega port engine. If you only want to use one muffler then I suggest a Racing Beat muffler only because you won't find another single muffler that delivers the same power for the noise output. If you want to use multiple mufflers, people like Borla mufflers and Magnaflow mufflers.

NCross

iTrader: (18)

Your MPG will drop.

teddyrx2

iTrader: (33)

con more noise, mpg drops more pollution blah blah blah....Pro's some more power gain, more breathing room, so on so forth...Best result Dual 2 1/2 or 2 1/4 as straight as possible till you get to the rear end don't go over, go under the rear end merged into a three inch pipe into a three inlet muffler for the best results...

Or:

Off the header collected into a three inch straight pipe straight back to the rear under the rear end and into a three inch inlet muffler...Believe me you will be happy with the results...

If you want to reduce the noise somewhat without restricting the car from breathing on the three inch exhaust use a stainless steel packed muffler with three inch inlets and outlets in the middle of the exhaust...

Jeezus

iTrader: (4)

3" on a stock RX? You must be crazy... I still think it was unwise for a 2.5". To each his own though

FirebirdSlayer666

iTrader: (3)

Yeah 3 inch is too much. A straight set up will destroy low end torque and power and it will be too loud to take it to the top end. Trust me, I ran open header for a while

Jeezus

iTrader: (4)

Open header sucks, I have even been in a car with NO header... half street half bridge.

Truth be told, RB says to keep your stock midpipe because it saw no real power gains from replacing it. I went 2.5" for either turbo or bridgeport, which is my next project...

NCross

iTrader: (18)

Open header, premix, with the first start on a fresh rebuild... Yep, loud and smokey as hell.

mxd

iTrader: (1)

I was to understand that the backpressure in a rotary only chokes the flow, and that excessive packpressure can destroy performance by means of the overlap. Doesnt the rotary derives its low end torque from the intake runners prior to combustion by increasing air velocity/density as it goes into the motors combustion chamber, and creating sufficient distortion/mix for a premium burn (ports considered) at idle. Isn't the exhaust diameter, and length relative to the exhaust temperature and velocity? Isn't the idea to move the hot gas a far distance quickly before it cools, gains density, and loses velocity (slows down and causes all gas behind to have more resistance). pop(combustion) zoom(down the pipe) POP(out the tailpipe quickly).

So a large pipe would allow too rapid of expansion of the gas slowing the entire process? Small pipe would not give the proper volume of flow at higher RPMs?

hrmmm..

FBsliderseven

iTrader: (2)

pros: you can shoot fireballs.
cons: loud as hell!

88blkiroc

As Smokey Yunik once said, "Anyone who tells you they know anything about exhaust is full of ****. Nobody knows anything about exhaust. I will tell you one thing though, too small is better then too big". I live by those words when it comes to exhaust systems. I think the only time exhaust size doesnt matter that much is after a turbo. The turbo itself creates all the backpressure the engine will ever need and after the turbo you just want to dump it as soon as possible. I really wish some magazine would do a back to back exhaust shootout where the only difference is pipe after the manifold. That would put a lot of myths to rest I think.

75beetle

I went straight back from my headers with a 2 1/4 all the way back to my muffler.Soon to buy a RB MUffler.Wat u think

buldozr

iTrader: (1)

I think we can all agree that more than 2-1/2" piping on an NA is rather pointless... 2-1/4 or 2-1/2 after the collector would be great or if running true duals, probably dual 2" pipe. Mufflers optional yet highly recommended

Jeff20B

iTrader: (13)

The 4 rotor is getting a 3" system.

The 20B is getting a 2.5" system.

The 4 port 13B in my REPU got a 2" system as did the GLC.

Everything is NA. No need for larger diameters.

panoz

iTrader: (1)

if you go straight from the header down, go with the duel system commonly found on ported set ups. slap 2 resonators one for each pipe, and add a racing beat muffler to top it off. and you will have a non restrictive quit, and smooth set up!

panoz

iTrader: (1)

i went that way and used a 2 1/4 set up!

openshot

i know custom header that go right up out the hood

jdm12a

iTrader: (3)

i had a 2.5 straight pipe on my 85 gs, i wouldnt recomend it. There is alot more power up top, definatly noticeable and the flames kick ***, but mileage went down from about 21 to about 19 but worst part is that its just to damn loud to do anything. I bought a jeep afterwards and could hear better on the phone at 55 with no top and no doors then in my fb.

NCross

iTrader: (18)

Maybe you should be concentrating on the road instead of your phone!

:P

trochoid

iTrader: (6)

This is the only post in the entire thread that explains and justifys exhaust correctly. I don't know where you clowns are getting the need for back pressure Back pressure causes more exhaust overlap and dilutes the intake charge. For those that have suffered less fuel mileage after an exhaust upgrade, get a clue, it's your driving that has reduced fuel mileage.