ok so theres a shop in town that has one of those million dollar mandrel bending machine so the place could easily fabricate me an exhaust and i'm hoping the place stays in business so i'd like to throw them a little of my business. the question is what size exhaust do i go with? i was thinking either 2 1/2 or a 3" turbo back single exit instead of dual. i've heard different things about different sizes. not sure where i remember hearing about loosing to much backpreasure and a little torque if i were to go with a 3" but i always figured the bigger the piping the better/cooler the car is going to run and due to the nature of the Rotary cooler is better. so me being a bit of a novice still when it comes to these cars i just wanted to get the opinions of some of the people in here. also i figured by going with a single it would save me some money and a wee bit of weight. any info or opinions are appriciated. thanks.

 

For the most power, Id go with a 3" turbo back. As long as your wastegate is ported, you shouldnt have much problems with boost creep. And mandrel bent would be the best. This is my plan for my exhaust, except Im buying sections of straight pipe and U-bends and welding it up myself. Wont be pretty, but it will be cheap. Basically it wont leak

And yes! Single is lighter, lighter is better!!

 

Since you are in the area, I would contact this man. He's the local Rotary Expert and RX-7 specialists.

As far as the OD of the exhaust, it depends on what mods you have now, what you plan on going with in the future, and other variables. You won't see the full benefit or difference between the two until you get the engine ported and upgrade the turbo.
Either setup will be a lot better then the stock $hit. If you go with the 3" you may gain more up top with a sacrifice in low end and torque.

Rotaries love open exhaust, but also like a lil back pressure.
The only way to go is single exit exhaust on turbo rotaries. You will save weight, gain power, save money, etc...
The true dual's only work good on the NA's and are more for look.

Just make sure you have a FCD, and that the boost stays down (no creep) and that you get the engine enough fuel.

Let us know how it turns out.

 

ttt

 

LOL!@!!! he is da man isn't he. now all he needs is a lawn tractor and a cigar.

 

i'm running rb 3" dp, custom 3" mp and apexi n1 catback. if you can run full 3" turbo back custom. its a night and day difference. might want to upgrade to a S5 turbo and manifold to prevent creep

 

the key factor in more upgrades is me selling the Civic.anybody know sombody who wants to buy one?

 

Doesn't everyone already have one?

 

Hey its "old *****"(inside joke) lol... you should get like a 10" pipe like those cool ricers with the green civic ex's.
-Ryan

 

or consult your local authorized deal "old *****"

 

Even on stock ports and turbo, there’s still a worthwhile performance difference between 2.5” and 3”. Plus you won’t have to rip it off when you do port it and upgrade the turbo. Why do people keep saying that? After a turbo, there’s no such thing as an exhaust that’s too big. More than enough backpressure has been provided by the turbo. The full 3” exhaust I fitted to my 12AT certainly didn’t cost me any torque. See above. Weight and money definitely, but not necessarily power. It depends on pipe/muffler sizes. True dual? It’s a turbo, you can’t have a true dual. And they're sure as hell not just for looks.

 

Anyone have any hard evidence that a single exhaust is better than a dual besides wieght? Im thinking 3rd gens had single(correct me if im wrong), im sure mazda engineers had a reason, maybe just space, maybe weight, who knows...

 

Yep, mainly space, but weight too. Note they've returned to dual parallel mufflers for the RX-8.

 

yeah it looks real pretty,saw it in person. its also not a turbo.