alright guys i am new to the rx-8 gig. i am currently looking for a catback exhaust, b/c the guy that had it before me punched out the cat and used an o2 sensor bypass on it. I want to get rid of the bypass and put this catback system on it. It claims to gain 21 hp at the wheels, i was wanting the borla exhaust. i have always been fond of borla but it only get 10hp gain. i also was looking at agency power but couldn't find how much gain you get. i am getting terrible gas mileage right now like 15 mpg. so any help would be appreciated. money is limited a little so nothing out in left field. lol

http://www.rx7.com/RPGReddyRX8exhaust/

 

no exhaust on an rx8 will add 21hp to the wheels sorry buddy u might be looking at 3hp gain to the wheels absolutely not 21

 

thats a manifold back system, not a catback.

a catback is just a muffler.

that and the system you already have already has all the gains you are going to get from putting an exhaust on an rx8. The only thing you would gain by getting the high flow cat and the muffler is no CEL and lightweight.

As for gas mileage, it really depends on how you drive it but down to 15-18mpg is pretty normal for an rx8.

welcome to rotary goodness

 

yeah i feel retarded now i didn't realize that was from manifold back. the est. mpg iss 22 and 24 so i figured at least 20 mpg but i don't get close to that. i figured b/c the 02 sensor bypass. you can smell gas out the exhaust. and i was wanting to get rid of the 02 sensor bypass. i have the service engine light on because of it. and i think it would sound better with exhaust rather than eleminating the cat. it also shows the dyno chart on that website. and they have video and sound of the exhaust.

 

HP gains have been debated for a while, but generally, when normal people dyno the exhausts(any) they show around 3-6 hp. and some show losses.

an exhaust that gains around 10 hp would need an amazing new manifold, a straight pipe to replace the cat, an amazing free flowing muffler, and a nice intake. You could maybe squeeze more but you would need a custom tune.

Thats just because the stock system is so good.

The supercat in that package is a good choice, I had it for a while, it will eliminate the smell and the check engine light, and also lighten up things a bit by losing the excess weight from the heat shielding.

The greddy exhaust also in that package has been known to be one of the louder choices, with the high flow cat its only going to be louder. But the tradeoff for the loudness is a lightweight exhaust, which will help your acceleration, handling and braking by just reducing the weight of the car.

As far as gains, since you already are running with essentially no catalytic converter, you have already gained all you are going to see with just muffler mods.

 

I have the Agency Power exhaust. I also installed their midpipe. Its a pretty good sound, a tad loud, but good. Ask (staticlag) As for HP gains, I wont know for a week or so, cause thats when I will be able to dyno. But I cant give accurate readings since Ive also put on an Underdrive pulley & intake.
I can find out what AP says there gains are for you if interested?

 

I love when companies put these crazy numbers on their websites..... almost nothing for our 8's will give us more than 5 hp (intakes, exhaust, pullies) there are only two things that will give us signifcant gains and thats going turbo/supercharger, or a midpipe......

 

the only proven way to get 21 hp without FI is with the alien body kit.

 

^thats great^

 

Really???

 

WTF?! That is actually ridiculously uncomfortable to look at... Please throw up a warning or somethin first...

 

^^^^thats F**kin hilarious........ what colors does it come in

 

I want one for Halloween!! I can't wait to drive around chasing little kids with my 21hp Alien body kit FTW!

BTW this thread's title fails!

 

Mysql did you do that with photoshop? This is some neat stuff

 

Back To The Catback Tread- I Have Re-amemiya Headers-stock Gutted Cat And Greddy Sp2 And Highly Doubt Im Gettin More Than 10 Hp- So 21hp Is Out Of The Question