To start, I have built and worked on many conventional motors. This is my first rotary, and while doing research on bumping horsepower a little on an NA I have become slightly confused. I've read opening up the exhaust is second to porting the motor in best way to raise NA horsepower. I've read that an open exhaust is best for power unless it's to big. Then I read that on a s4 that opening the exhaust will cause the 5/6 port not to open correctly because the actuators are ran on exhaust pressure. What is the best way to open the exhaust without hurting the port actuation? Will stock manifold with open 2.5" exhaust to a n1 muffler be okay? Completely new to rotary so I'm still trying to figure out how these motors work completely. Not in a big hurry have to put the whole car back together. Just curious as everything has me thinking in circles.

 

Any open style exhaust is going to be way too loud, the Racing Beat line of mufflers and exhaust components is very popular on the rotary and you're correct some have removed the cat system and replaced it with a "test pipe" and resonator then welded a tube in order to charge the stock system

 

So if I removed the cat, I would have to run a new charge pipe for the actuators? Or there aftermarket hi flow cats that have these tubes? I would probably put a center muffler on before the n1. Around here you can get away with a lot. Most trucks run straight piped as does my buddies srt4. It will mainly be a drift car and weekend toy. Thanks for your help.

 

Check out the Racing Beat stuff.
It has a Header and Presilencer that has the tube to hook up the Aux ports.

You may want top research 5/6th port activation to get familiarized with what you want to do.
The S4's need the Exhaust back pressure OR a system that can activate the ports.(look up electrical aux port activation)
The S5's use the air pump.

 

I think I will do that air pump mod once I get it running. Get a header and have the local shop (friends with the owner) to weld me up a custom straight pipe. Run a glass pack halfway through then the muffler at the bumper. Thanks for the advice. Makes it so much easier.

 

Why NA if you want it for a drift car? im sure the 40-ish extra power on a turbo ii car would help not to mention a lot easier to get more power out of in the long run.

 

Because that's how the car comes. Being new to rotary I don't want to complicate it more to start. And I also want to learn to drift in a low power car before going turbo. Eventually it will be turbod.

 

you'll fry that glass pack.It will literally become toast.(exhaust temps on a rotary are higher than piston engines)
Save your money.