buckfutter125

hi, i am doing up my 12a and am to the point of putting the exhaust on. I got a custom made stainless steel header and am planning to run 1, 3" exhaust pipe right to the back. Heres my question:
what would be the best type of muffler to put on if i want it too be kind of loud but more when i open the throttle up. And to also give it a nice sound with the most horsepower possible?

ben79

A 3" exhaust is probably a bit much. unlike a piston engine, the rotary likes a little back pressure. the only ppl who do 3" exhausts are running turbos and ports, i believe.

MIKE-P-28

iTrader: (1)

If you want it loud just leave it open header Im gonna run 3" on mine, but its a 13b-RE single turbo set up

BTW: Dont know about that nick you got Id change that if it were me

SuperPhly

can we run open headers on a 12a NA?

peejay

Yep! That's how I'd drag race. Bring the earplugs.

REVHED

Rotary's do not like back pressure. The less back pressure on any engine the better.

The reason you don't wanna go too large a diameter is because you start to lose exhaust gas velocity.

MIKE-P-28

iTrader: (1)

I also know another thing that was a NO NO , in my personal experience. I once replaced the 3 cats with a pipe larger in diameter than the one in front and rear of, and when I changed it to the same size the car ran better. Just my experience

mperformance

I'm running 2 2" to one 2 1/2" and a dynomax at the end...and it's freaking loud and I'm not even ported yet!

ben79

Oh....high velosity, low back pressure. Alright, i just remembered reading something about how ppl were surrprised that the rotary didn't like completely open exhaust, like the only header set up. i don't remember where that came from, but i might go back and search...I was guessing that it was because of pressure....

4ohfour

If you had a street ported 12a with the exhuast ports bored nice and big, what would be the best diameter for street racing (stop lights and other such instances) I won''t be going down to the track alot, and this will remain my daily driver, but as I am over hauling the engine i figure meh, why not...

so whatcha thing, would 2 1/2" do it or should i go 3"?

cheers'

REVHED

Yep, 2 inch headers and 2 1/2 for the rest of the system.

jeremy

iTrader: (1)

all engines need to have as much velocity in the exhaust wthou a lot of backpressure to scavenge the chamber clean. this, inturn, allows more room for a cleaner mixture. it applies to rotors and pistons.

Winnipeg85GSL

Hey buck : what color is your car and whereabouts do you drive around.

85RX7GS

iTrader: (1)

Physically speaking, if you have different pipe sizes, the velocity of the air will change when moving from one medium to the next. The pressure will also fluctuate, so I'd just stay with the same diameter pipe throughout.

hanman

Buck,
If you don't put a presilencer on your system, you are going to find out what loud is. You will be getting regular visits from your local constable on patrol. Or maybe the mounties where you are......ha ha.
Seriously, you will not want a system without a presilencer or a cat if you are going to use the car on the street.
hanman

OtakuRX

iTrader: (1)

so just a muffler is a bad idea??

mperformance

yes...I will be putting a presilencer in mine. OUCH unbearable

error402

I have a custom stright piped system with a muffler that you can see through. I can only say on thing. It's LOUD.

OtakuRX

iTrader: (1)

ah, hm. well might have to deal w/ loud for now.

NanaimoRx-7

I had the same setup as error402 when I first got my headers...it lasted for about five hours of driving before the red and blue lights showed up in my rearview. It's the sweetest sound in the world when you're racing around the back roads with the pedal kissing the metal, but it's just damn annoying in town.