Is there a limit to how much you can open the exhaust up on a gsl se? I was planning to get a header then have a custom system built thats straight piped perhaps about 3" is that a bad idea or what.... if it is where can I get an exhaust system and header. thx matt

 

I went to 3" on my 12A from 2.5" I didn't notice any difference other then it seems louder. Don't waste the money on 3" if you aren't going Turbo there's really no point. Do 2.5" . Oh yeah go www.Racingbeat.com

 

Since you mentioned that this is for an SE - if you are currently running your '6'-port configuration as designed, if you change the exhaust tubing diameter, you will likely not build up enough exhaust backpressure to actuate your '6'-ports after installation. The only systems out there that are advertised for being able to work with standard intake on SE's is the Mazdatrix (Racing Beat) header and presilencer that has been installed with both O2 sensor bung, and the bypass pipe that actuates your '6'-ports.

I run this system right now and it operates as advertised. If you open up your exhaust by using larger tubing, the pressure will go down, but you may see a counter-current loss of power due to loss of your '6'-port operation - this would not be moving in the right direction.

In rotary engines, unless you're on a full-race design, there is really no need to use larger than standard sized exhaust tubing. The rotary engine operates very well with a little bit of exhaust backpressure to develop torque at usable powerbands. If you release this backpressure, as in straight pipe exhaust, then the powerband and torque curves go way up, and you may not see usable power until well into redline for a street driven car.

There are plenty of excellent aftermarket exhaust systems out there that work very well for street. The only one I would avoid is Pacesetter often sold by JC Whitney catalogs. Racing Beat or Mazdatrix both sell quality units.

 

It'll be illegal, but go for it if you can sneak it passed inspection.

And yes, Racing Beat has what you need. Best out there for 1st gen's.

 

hehe well as for the illegal part its already been straight piped.. so I noticed last night when I had the car on the lift... the bypass pipe you speak of that opens the 6 ports... its a small diameter tube perhaps 1/4" wide? if so its not attatched to the pipe, which might explain why it feels like its down on power, so basically get the racingbeat header? lol sounds like a plan

 

yyyeah...hehe...

That pipe (air pressure sensor or something like that) will connect to the Racing Beat Presilencer, which I think is the alternative to your old monolithic converters.

I'm about to order RB headerand presilencer too.

 

Another person with the bigger is better theory. It's not true, the biggest you want is actually 2" after that you start losing horsepower because you lose exhaust velocity. Exhaust is loaded with energy, kinetic, thermal, and sound, interrupt one of these in anyway and you lose flow, muffler, collector, ect. You also interrupt kinetic and thermal by going too large with diameter causing the exhaust to start "piling up" and cool down too quickly because the huge diameter cannot retain as much heat.

 

You can find used RB systems for under $400 shipped if you are patient. Half as much as new including shipping, and the o2 bung.