what is your solution to this? i have gotten pulled over twice for the exhaust and had to get its tested. a racer told me to have a bunch of cones welded together and to put a dump on it. I dont want the car to lose the rotary sound. so whats your ideas

 

throw a cat in there.

 

Yes a cat is fine too.

 

put a turbo on it? :]

 

carry a copy of the local regulation with the sound limit highlighted. attach official copy of dB test to prove you are 2 dB quieter than the max legal limit for road vehicles...

oh, and a downturn exhaust tip will make it sound a little quieter too.

 

Take your RB Road Race Header, and buy the centre section and muffler to go with it.

I've got the whole Road Race setup on my car and I've never had any sound troubles at all. In fact I'm quieter than most cars on the road, and I love the sound of it. When you really open it up you can still hear it, but around town it's perfect.

Jon

 

How can a turndown tip make it quieter? From what I understand, having a downturn tip will make it a bit louder because the sound will be ricocheting from the ground.

 

Please don't bash if I'm wrong.
The way I see it is some of the soundwaves are absorbed into the ground while most bounce off. The soundwaves absorbed into the ground aka vibration will be quieter than reflected soundwaves. Also the distance of the sound has travelled has increased also quieting it down. Ex. you stand next to a car at idle then move away 10 meters, which will be quieter?
I also think this noise difference, straight tip/down tip, will be hardly noticeable.

My 2 cents.

 

^ Ways, y'know I did think about that. The whole "ground will absorb the sound" bit but still I was trying to figure out in my head just which way it really does go.

Only one person told me that the exhaust note would be a tad louder, but that was quite a few years ago and my memory fogs up now and again. Tho, how you explained it does make much more sense. It could also depend on the "bass-ness" of the exhaust note? I had a pickup with a big V6 in it and I had no muffler and a turn down tip on the end of the pipe. The thing had a good bass sound to it.

Maybe it depends on if the exhaust produces more bass than treble, and vice versa, that depends on the absorbtion and reflection? We need a scholar here. *L*

 

the turn down doesnt actually make the car quieter, but it dissipates the soundwaves in different directions. its like throwing an apple at a wall...the total amount of the original apple will be there, but the pieces will travel in different directions, and have less force than the whole apple.
i dont think that helps, but i tried!

 

^^ That's true if you're measuring the sound intensity right at the exhaust tip. But it will make a difference if your measuring at some distance where the sound has time to dissipate, like 2 feet away for example.
To dissipate means there is less intensity in the sound which means you hear a quieter sound.

 

In CA,they measure from 18" away at 45* angles from the tailpipe.
A turndown will direct the soundwaves into the ground and they will have to bounce off the ground before making their way to the decible reader.Each time they reflect,some energy is lost....just like an echo fading away in a canyon.It might not make the difference,it depends on how bad you are over the limit but it cant hurt,and turndowns look good anyways.

I got popped once by a Sheriff and had to test.I passed CA standards by two decibles with my turbo/single cat/RB muffler/3" system with shotgun tips.I got the ticket thrown out in court,and I read that more than half of the decible test tickets are beaten and thrown out.They just hope you would pay the 65 bucks and forget about fighting it.Then,just weeks after my ordeal,they started to charge 35 bucks for the decible testing.......so they get thier money whether you win or lose.I keep the certification in my car with the regs so if I ever get pulled again,Ill have some leverage.

 

well first i am not going to put a cat on it, not going to put the racing beat stuff on because i dont like the sound, i am going to put that turn down on it with other things

 

So if you reject all of the advice that we gave you, then why even ask?

 

He is using some of the advice gave from comments and not using some of the advice....whats the problem with that...

 

RB Primaflow muffler is one solution.

 

a solution i wanted was one that wont kill the performane and the sound. i al just going to use reducers from flowmaster and put them front to front and back to back, that should quiet it down with a turndown ( local racer told me this).

 

If your unfamiliar with my setup,RB mufflers dont kill performance.Quiet does not equal restrictive,and you get what you pay for in quality and longevity.

They are very quiet,especially the standard mufflers.But the streetport version lets out quite a big of sound,hence my passing score that was only 2db below the legal limit.The SP version also has a 2.5" inlet which is more than enough for most N/A engines.I easily enlarged it to a full 3" which is enough for any N/A engine and nearly any turbo engine.

 

any one got a sound/video clip of the RB muffler SP version?

 

Ill see if I can get one tommorow, of my car.

 

The solution is to have tidy looking car in and out. If there's no obvious things to get pulled over for you're more likely to be left alone. Funnily enough I haven't been hassled about noise once in the three or four times I've been pulled over (13B PP)

A Rotaflo muffler would make your car sound deep but still legal

 

here we go again. RB system is quiet period but look at the materials they used...its a complete bolt-on if you wanna mix match it with the stock sytem. You come up with your own conclusion why it is quiet.

I have owned it in the past, went to a different set-up and then went back to RB then I junked it for good. For stock to mild, it may work but for large ports, it will hurt at the end.

 

point the exhaust tip down.....

 

pre-silencer!

 

Heres a short vid of my car idling, and going all the way up on full throttle.
Its a bit louder when under load and the turbo spools,but the sound changes from the rotary blat,to a typical turbine jet-whoosh.......


http://smg.photobucket.com/albums/v2...evepics014.flv