Omicron

Exhaust discussion here, and intake discussion here. Happy reading! :D

epitrochoid

the best intake is the one that's on the car now. stock.

RXhusker

I think you will be surprised at how loud the Borla (or B&B) will be with a midpipe sans resonator -- the rotary will by MUCH louder than the 6 cyl 350Z. Rotaries are known for how loud the exhaust is. Vivid Racing said they got flagged AT THE TRACK for how loud the B&B is with a midpipe but no resonator -- I think it will be too loud for the street. I almost feel self-conscious driving around my neighborhood with just the Borla cat-back. I am getting CZ's midpipe with the resonator.

I love the story in Mazdasport Magazine about the open exhaust RX-7 that will blow out windshields of other cars (like the Porsche they passed at 175 mph and then let up on the gas so the high-pitched exhaust would blow out the guys windshield :D )

Don't forget -- if you remove the cat you will need an O2 fooler or it will CEL.

I started my 8 without the exhaust when I was installing my Borla and all the neighbors on my street came out to see what the unimaginable roar was -- unbelievable sound :D

epitrochoid

Do you think the midpipe/resonator with the borla will keep the sound levels at a sane level? I just can't have another loud car, it's so damn annoying, especially in a $30k car.

BTW: send me some pics of your car with the tint, im lookin at HO myself

RXhusker

I am trusting Maurice on the sound of the CZ midpipe with resonator. I believe he has stated that it is louder than stock but acceptable. Without resonator -- for track only on the sound level.

epitrochoid

you'll have to hook us up with a sound clip. that with the borla or the sp2 is my intended setup once i go stage 2

rotarygod

It's funny because I was going to say nearly the same thing. The stock exhaust is cheapest and only makes a few horsepower less than the rest.

JeupRX-8: If you replace the exhaust with an aftermarket system there is no "best" system. What defines "best" anyways? Is it the most power at peak rpm's? Is it which one makes the most average horsepower? Is it which one is the loudest? Quietest? Least raspy? Tone is subject to opinion. You get the picture. I suspect that you are wondering which one will give you the most power gain on a dyno and this would imply the most peak power (which is also the LEAST relevant issue). The answer is going to be hard to come by since different places test differently and I've never seen the same base numbers. None of the aftermarket systems will have any noticeable, feelable advantage over the other. Some of the ricers out there think that their systems are faster just because they are louder or because someone else says so. Don't fall into this catagory. Realize that most every system will be very comparable to each other in the power department and none of them will make you impressively faster if at all. The sound of each system will vary widely though so decide which one sounds and looks best to you and choose that way. If you try to decide based soley off of power numbers you aren't going to get very far.

Dookie_Rx-8

anyone have a sound clip of that LOUD SOUND i want to hear it....i think we all want to hear it

Gord96BRG

On your automatic RX-8, you will not be able to get anywhere near 20 hp with exhaust modifications - you might get 5, maybe. The manual high-power Renesis engines are making more power with exhaust changes, but even then they won't get 20, maybe 10. Your low-power engine, with fewer more restrictive ports and lower revs, simply can't benefit from freeing up the exhaust as much. Similarly, an intake will be worth nothing on an auto RX-8, because it only helps on the manual cars above 6500 rpm to 9000 rpm (and then only by about 6 hp max), where your auto can't go. At 7K redline, the breathing is not restricted on your car by the stock intake, so an aftermarket intake is of no benefit.

Regards,
Gordon

rotarygod

It's not the manual owner's that are raining on your parade, it's physics. The plain and simple fact is that you bought the slow version and that it has little potential without forced induction. Even then you are severly limited. Here's a thread that I wrote that expains it all in technical terms:

https://www.rx8club.com/showthread.p...threadid=20148

brothervoodoo

I don't think Gord96BRG or rotorygod are being overly negative. I can see their point about spending all that money when you are not getting much return in terms of performance. If you are going just for looks/sound than that's a different story. It's your money afterall.

rotarygod

Most of the gains out there are primarily around peak rpm yet don't do hardly anything anywhere else. This isn't usably faster unless you want to consider a lighter wallet a weight savings. Manufacturers highlight peak hp gains as opposed to average horsepower gains. Peak horsepower sells product, average horsepower makes you faster. They only care about selling product.

Shocka

actually i must say this thread is getting into a really informative thread. Being that I have a civic; Simply putting in an Intake made a difference (VTEC hehe), then exhaust and headers.. it was something i could tell. But the car would too loud so i got rid of the exhaust n headers and went back to stock also helped with the down towards the rx

as for the RX-8 it seems that the stock setup isthe best possible so far. but besides an ECU how else can we gain some power.
I am not looking into racing but i would like to get a lil more power outta the car.

I am a newbie in the performance dept i guess. Oh wise ones share your infinite wisdom with us.

I was thinkin of getting the GReddy SP2 but now it seems like a waste of money, and i really dont want a louder car i HATE MY CIVIC for that.

rotarygod

You can't compare one engine to another in terms of performance potential. The Renesis is pretty close to its max potential right now (assuming it is tuned properly). The 4 port engine has very small ports and not alot of port timing. After the air traveling through the ports reaches .6 mach there are no more gains to be had and power will fall off. So revving it up higher is out. Also if the exhaust and intake already flow as much air as the engine can already use, there really isn't going to be any benefit form changing anything and therefore not much extra power available.

Mazda did a very good job with this engine but many are still in denial over it. People complain about 238 hp and such but remember that the last nonturbo rotary was only 160hp and was a much dirtier engine. That difference alone is huge and was very hard to improve upon for almost 30 years without forced induction.

It's time to face the facts and get over the denial. The 4 port engine has so little performance potential over what it already has that it almost isn't worth touching. If you want an engine with more potential, buy an engine with more potential but that one isn't it.

HKSpower

Any of you guys using Amuse exhaust ?

rotarygod

Trust me, we will see 300hp naturally aspirated Renesis engines out there in the near future. It can be done. It just takes time to figure out.

If your friends Z gained 30hp from an exhaust and an intake you shouldn't be impressed. That doesn't mean that the engine has potential. It means that Nissan didn't do a very good job at maximizing their product. Mazda did here too but they skimped on the ecu. Easy fix. They did everything else very well to begin with which is why gains are going to be few. A little retuning on the 6 port engine in conjunction with an intake and exhaust will get these engines up another 40 hp or so.

Lets go look at the little weakling Honda engines in the Civics. 1.6l of raw something. These little cars come stock with headers. No one else does that. This is why the ricers that change them don't really get much of a gain. The aftermarket intake manifolds have shorter, higher flowing runners yet the cars lose power in 90% of their usable powerband. Sure you can change the cam, pistons, compression ratio, valves, etc. You can do the equivalent on a rotary too. We call it porting and this is good for some more power as well. These little Honda mods don't do crap for power although their owners will claim otherwise out of denial. I have a stock Civic EX. 127hp from the factory. Just for grins I raced a little ricer in the same type of Civic one day who had his exhaust and intake and a Venom intake manifold. I wasn't the slow one. OK I was the slow one but he was slower! That engine was a joke. He made up all these excuses but the reality was that there isn't much to do to those cars to improve them without taking the engine apart.

The race rotaries can get up near 350 hp naturally aspirated horsepower from a 2 rotor. Now that is impressive. They can go to stratoshperic rpm's and stay there all day. The race engines are in no way streetable but neither are piston race engines.

How can you say that the rotary is poor for aftermarket tuning when all of the past rotaries would get much larger gains per dollar spent than their piston counterparts and I'm not referring to turbocharged models? The RX-8 is so new and no one is patient enough to wait for development. Give it time. The power will climb when we figure out where Mazda left us room to improve. Every engine has is. This one is just better to begin with.

XDEEDUBBX

seems to me that troy bought the car for the wrong reason..( i mean his dad)... like millions of other threads say, you should have bought a z or a evo if you want that type of power... Then again you are 18 and don't know much... Next time do research and don't be so negative...

MazdaManiac

iTrader: (3)

Um, the Miata comes with headers, too.
Nice, big 4 into 1 job. :o

rotarygod

Well that's cool!