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EXTREMELY exciting exhaust idea. Exhaust specialist wanted

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Old 05-07-2011, 02:20 PM
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EXTREMELY exciting exhaust idea. Exhaust specialist wanted

I'm sure this has been done before but here's the back story. I just ended up having to take my exhaust off my 06 rx8 and just to see what it was like, i started the engine. I have to say.. it is the most amazing, beautiful, loud sound i have ever heard. I'm a college kid and i don't REALLY have 850.00 for the agency power exhaust. So here's what i want to do.

Right at the engine exhaust, before it gets to to the catalytic converter, i want a y pipe that connects one end to the catalytic converter, and the other end will exit out the side of the car. Inside there will be a valve that i can operate from inside the car to make it open or close from some sort of lever. When it's closed, the exhaust will exit through the cat exactly like it should. When it's open, it will bypass the catalytic converter and exit out the side

Has anybody heard of this? And if so where would i find a valve that would be suitable for this? Or does anybody have an idea of how i can accomplish this? I have a welder and i can buy the piping.
Old 05-07-2011, 02:34 PM
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I have seen this before and have a friend that did this on his camaro as it is very common with the muscle car guys. The problem is, the actuators are so prone to heat damage that there are times that the actuator will stop working and now you either have the pipe always in position A, or always in position b.
Old 05-07-2011, 02:36 PM
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FYI this is something you are looking for, they are called electronic splitter valves

http://www.dmhperformance.com/photogallery.htm
Old 05-07-2011, 02:48 PM
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Here is what you would need. (plus the cost of the custom work)
http://www.jcwhitney.com/electric-ex...wx?filterid=j1
http://www.jcwhitney.com/y-pipes-for...wx?filterid=j1
Old 05-07-2011, 05:10 PM
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but with that done on our rotary, you will completely loss all the back pressure, not only it sounds like ****, and it even drive like ****.
Old 05-07-2011, 05:46 PM
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I just dont see the point. I mean, with the cost of custom work and parts, you can get a really nice resonated midpipe and solid exhaust. If you cant pass emissions in your area with the midpipe, you sure as hell cant pass emissions with the splitter
Old 05-07-2011, 05:54 PM
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Honestly I would not feel safe doing this.

Like you, I thought it would be cool to see what the car sounds like with no exhaust. So after I took off my stocker, I started it up and revved it a little bit. Then I got out and let my friend rev it. A ******* ginormous flame shot out under the car and I told him to cut off the engine.

Our engines run so ridiculously rich that I would not feel comfortable with the exhaust ending right under the car. One of my friends used to tell me that sometimes, flames would actually stay "lit" for a couple of seconds before they went away (This was when I had an agency power midpipe and greddy exhaust). If stuff like this happens with a full exhaust system then I really don't want to know what would happen if I shot out the same flames directly under the car.

Now, a custom sidepipe... now we're getting somewhere
Old 05-07-2011, 06:01 PM
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How would you fit a sidepipe though? The valley has no side outlet to not interfere with ride height and road hazards
Old 05-07-2011, 06:22 PM
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Originally Posted by MC8jai
but with that done on our rotary, you will completely loss all the back pressure, not only it sounds like ****, and it even drive like ****.
I'm not agreeing with his idea, but your reason is completely flawed. Rotaries don't need back pressure at all unless they are turbo'ed, and then it isn't the engine that needs it, but the turbine, and even that is somewhat debatable depending on the turbo, spool, flow, etc... For rotaries, the best possible power is completely unrestricted exhaust.

"Back Pressure" in piston engines is just a mistaken term for exhaust velocity. Pistons need the exhaust velocity up to help pull exhaust from the combustion chambers, higher velocity generating more of a low pressure in the exhaust system to accomplish this, and EVEN THEN, it's still based on RPM and port sizes, etc... You can go straight to atmosphere completely fine on a piston engine if you stay at the top of the power band, you will just have massive power problems down low.

Originally Posted by Grog
Our engines run so ridiculously rich that I would not feel comfortable with the exhaust ending right under the car. One of my friends used to tell me that sometimes, flames would actually stay "lit" for a couple of seconds before they went away (This was when I had an agency power midpipe and greddy exhaust). If stuff like this happens with a full exhaust system then I really don't want to know what would happen if I shot out the same flames directly under the car.
^ this is the BEST reason NOT to do this.

Take a look at this video, and ask yourself if that is what you want happening right under the passenger's seat, next the fuel lines and stuff
http://www.youtube.com/watch?v=v5yiYB3kp54
Old 05-07-2011, 09:04 PM
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Originally Posted by RIWWP
I'm not agreeing with his idea, but your reason is completely flawed. Rotaries don't need back pressure at all unless they are turbo'ed, and then it isn't the engine that needs it, but the turbine, and even that is somewhat debatable depending on the turbo, spool, flow, etc... For rotaries, the best possible power is completely unrestricted exhaust.

"Back Pressure" in piston engines is just a mistaken term for exhaust velocity. Pistons need the exhaust velocity up to help pull exhaust from the combustion chambers, higher velocity generating more of a low pressure in the exhaust system to accomplish this, and EVEN THEN, it's still based on RPM and port sizes, etc... You can go straight to atmosphere completely fine on a piston engine if you stay at the top of the power band, you will just have massive power problems down low.



^ this is the BEST reason NOT to do this.

Take a look at this video, and ask yourself if that is what you want happening right under the passenger's seat, next the fuel lines and stuff
http://www.youtube.com/watch?v=v5yiYB3kp54

WOOOOW... this is true.. i didn't think about that. So is the agency power exhaust my best bet? I want something that really brings that rotary sound out and sounds loud, crisp, and defined. I do NOT want a fart can. I was thinking about the agency power full exhaust including the cat delete pipe. Is this the loudest, closest to unchanged rotary noise out there?

OR what if instead of a side exit, i just ran a pipe straight through to the back? Well.. no theres no way to make it exit.. ok.. sport exhaust then i guess.
Old 05-07-2011, 09:11 PM
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midpipe + hks hi power is loudest/
Old 05-07-2011, 09:13 PM
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Originally Posted by Frostbytes89
WOOOOW... this is true.. i didn't think about that. So is the agency power exhaust my best bet? I want something that really brings that rotary sound out and sounds loud, crisp, and defined. I do NOT want a fart can. I was thinking about the agency power full exhaust including the cat delete pipe. Is this the loudest, closest to unchanged rotary noise out there?

OR what if instead of a side exit, i just ran a pipe straight through to the back? Well.. no theres no way to make it exit.. ok.. sport exhaust then i guess.
The best SOUND (granted, in my opinion), is a Borla cat back with BHR mid-pipe. BHR's midpipe won't break down like other pipes (There is no packing to break down, mine is perfect at 20k miles), and retains the core tone of the rotary without making it rice.

The Agency Power midpipe with the HKS High Power catback is the pure loudest. However, it will rasp and buzz your ears off, it's obnoxiously loud, even to the driver, not just everyone else. It's been accurately described as "attacking an aluminum shed with a chain saw". Every midpipe other than BHR has packing inside to attempt to mitigate this, and the packing can't stand up to the rotary's heat, and will break down / blow out. The cheaper the midpipe, the faster this happens, the cheapest only last 3-5,000 miles, the more expensive ones get closer to 10k, but rarely over it.

Do yourself, your ears, and everyone around you a favor and avoid going for maximum noise. It isn't pleasant, it isn't appealing, and it isn't something you will be able to stand for long. It's also something that will attract cops to you like nothing else.

Go for good SOUND, not big NOISE.

Of the cat-backs, the HKS High Power is the straightest, and the loudest, but I'd personally say the tone isn't pleasant. Add a bad midpipe just makes it worse.
Old 05-08-2011, 02:30 AM
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The concept of needing backpressure for power..
Old 05-08-2011, 02:40 PM
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combination thread and hearing fail ...
Old 05-08-2011, 03:55 PM
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OMG this IS extremely exciting...
Old 05-10-2011, 08:22 PM
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Do you know what would REALLY be extremely exciting?

::: drum roll :::

If you posted your S1 posts in the S1 section of this site!

Another thing that would be extremely exciting is your car on fire! Now that would be a YouTube video for the masses...

Can't you pick up an AP exhaust for $500 something? Use those personal planning skills they teach in college and SAVE MONEY!
Old 05-10-2011, 08:55 PM
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http://vimeo.com/21846970

Racing Beat header
Exotic Speed Race Pipe
HKS Hipower

The only way to go louder is with a test pipe (no resonators)
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