Up until a few weeks ago, my main ride was a 1986 Nissan 300ZX Turbo (broke a timing belt...interference engine with aluminum heads = destroyed motor). Decided when it went that I wanted something more reliable (every two weeks, like clockwork, the Z had some issue that required it to be parked until fixed), lighter (Z weighed about 3200lbs), and better handling (230 horsepower was fun, but man the nose of the car would point to the sky when you got on it...*really* shitty suspension stock).
Ended up calling an owner of a 1989 Mazda RX-7 that he'd stripped down, put a 6-point cage into, and raced for a while. Motor had less than 6,000 miles on it since a rebuild a few years ago (granted, the most recent of those were probably pretty harsh), the suspension was in great shape, and the car was in great shape minus a few patches of peeling paint.

Turns out it wasn't just any RX-7, it was a GTUs.

I almost turned my nose up when I heard it only had slightly over 160hp (was ignoring power/weight). Glad I didn't pass it by. Holy cow is this thing ever fun...sticks like glue in the bends, and the 8k redline is always a hoot ("Dude, shouldn't you shift?" "Nah, it's only at 6500, it's got some room to go still"). The only downside is that it just isn't as fast as my Z, and I saw no real way to get it there without plunking down a huge amount of money for a turbo.

But then someone mentioned to me that a rotary responds *much* better to exhaust upgrades than a standard piston engine, sometimes to the tune of 30hp more.

So, I'm in the market for new headers/exhaust/mufflers for the RX, and hoping to spend $500 or less in parts. Power is a priority. Quiet is always good, but not a must if it means the difference of 15 horses or so. I'm now realizing that each extra pony I squeeze out of this thing makes much more difference than on the 3200lb slug of a Z.

Anyone have any recommendations for the best exhaust to put into a second gen non-turbo RX-7 to get the most power? Eventually this car will be doing laps on open-track days, but for now it's just a weekend autocrosser.

Either post a reply here, or shoot an email off to ThrottleOversteer@gmail.com. Greatly appreciated!

 

Also worth noting, there are no emissions tests in my county, and all the enviro-friendly stuff has been removed from the airflow, with the exception of the cats (they're still in).

 

Welcome to the Rotary world, Waldowin! I think a saw that car for sale somewhere...had no idea it was a GTUs!
I'm not really the one to answer your question, but maybe you can find a good deal on a used exhaust in the NW Forum/for sale thread. I don't think $500 bucks will get you a full new exhaust system though. I still have my stock exhaust on my GTU, but knew I wanted a Racing Beat system to go with my Turbo-II (~59HP gain). Racing Beat designed their systems specifically for RX-7's, so you know you are getting the right performance for your vehicle. Personally, I'd rather pay a little more for performance than go with a cheaper, louder & lesser quality system. Keep in mind that the exhaust on a rotary runs somewhere around 500 degrees hotter than a piston engine.
Maybe you could also try the forum search tool...I'm sure that same question has been asked hundreds of times before.

Remember to keep your Rotary running cool at all times- Heat kills!

See ya around town or in the forums,
Dave