I'm considering a new system from my custom one. I was contemplating the RB TII race system. I understand that i would have to modify the DP to fit my TO4B, but that's the least of my worries. I am conserned with flow VS Noise attenuation. I would like a quiet system that can support 400RWHP. The current set up i have is single and is nice at idle all the way to 60 mph. At 70 an annoying drone comes online. continues up to 80, then it just gets loud after that. I understand that sacrifices will be made, and i'm looking for good compromise. If Porsches and ferrari's can do it then why the hell can't we.? I was thinking of using a 3"DP to y pipe, then dual 2 1/2" pipes. each 2.5" using a borla xr-1 for a resonator and then an n1 for a muffler. Dynomax also sells resonators, but i don't know their backpressure numbers and temp tolerances, but i may consider their desing instead. Any clues, as to if this will flow enough. Right now it's just a 3" turbo back. No cats!

 

Mazda's stock setup reduced noise by running two catalytic converters (85% of the noise reduction) and mufflers (15% of the noise).

What ends up happening is a downpipe & performance cat only reduce the noise by 60% and HKS mufflers by 10%. So now you have 30% of the noise from the engine coming through. If you have a gutted cat, "test pipe," or glasspacks (like me) - it's even louder.

If you want near silence, you can get it with a RB setup, but you'll need to run 1-2 presilencers.

You could also do the removable muffler silencers as well - so at least you could get muffeling when you want it.

 

I'd just keep your 3" turbo back single system (it's just piping and 1 muffler right?) and add in one large pre-silencer somewhere in the middle. (or two smaller ones)

Single is the way to go on turbo rotaries... more power and less weight. Can't get any better than that.
3" diameter piping is also an optimal size for a turbo 13B making between 275-450 rwhp. It will flow excellent for your T04B setup.
Are you using mandrel bends? If not... do it!

The pre-silencer(s) will lower the volume of the exhaust substantially, make the sound of your exhaust deeper, and also help to get rid of any drones and resinance.

 

i dynoed my car with and without the rb turbo back, and it looses about 3-7rwhp at the 200rwhp level, and its stock like quiet

mike

 

you mean you ran it with NO catback on and it lost 3-7 when you put it back on. the more power i make the more i will also loose. I already have a Borla XR-1, which is a race muffler. 3" in/out. it's agressive and deep at idle. I would like it to be a "little" quiter at HWY speeds. I need info for resonators and mufflers on the market. backpressures and such. Modern Matrix style converters only add about 2psi back pressure and reduce sound minimally. My friend n/a was cat-less and we a added hi-flow cat from Random technologies and it didn't change the sound at all. Idle or hwy speeds

 

As usual when it comes to something really technical, but a handful of people can answer intelligently. I'm taking this to the single turbo forum. I should have asked "can i put S5 taillights on my S4"

 

Bah, again, if your going for streetability. Get the rx7.com 50mm catback. Its not big piping. But it gives a good note. On my to4 hybrid, I put down almost 300rwhp with untuned microtech , stock topmount, with the rx7.com catback... Granted, Im getting a better catback, but in your case. You can generate the power with a smaller exhaust...... Just depends how **** you are for 10hp?

Well, I got thinking, do you have a streetport??
In my case, with the large streetport and the ability to generate power up to 7.5k, my 50mm catback kills that topend. But, without a port, your not going to get good power much past 6.5-7k which the smaller exhaust won't make as much difference.

matt

 

what's 50mm in in inches.....like 2 1/4

 

i have the rb full turbo back system, and i took it off after the dp, so i dynoed with the exhaust, and then again with just a downpipe. it made between 3-7rwhp more with just a downpipe. and you can put s5 taillights in an s4, super easy

mike

 

How loud is it when cruising with the full system. Compare it to something like road noise, or having a conversation inside.

 

its a tad louder than stock, but its a lower note

mike

 

I have the RB turbo back system on mine and I run with the presilencer and it is quiet on the hwy it has a low tone doesnt annoy me at all. It was the best 800 bucks I have ever spent my buddy has the Apexi N1 system and is very loud I wanted sleeper so I got the RB. It is slightly louder than stock. Hope that helps.

 

with the windows up I need to turn the stereo off to hear mine... stereo on you can't hear it.

 

1 inch = 25.4 mm, therefore 50 mm = 1.96 inches.

 

the radio thing is true

 

hmmm Maybe there is something wrong with my exhuast, because i just got it on about a week ago and I love it. Single n1 with 3'' dp/mp. I thought it was going to blast the hell out of me like open downpipe...but it sounds great to me :shrug:

 

I'm also very fond of the rx7.com catback (actually add that to the Bones superflo and damn it just doesn't get any better ), for a turbo and one that wants max hp I wouldn't do it though. You'll have some damn spiffy tq, but you won't have that hp number that you're after (at least I somewhat doubt it anyway), not by a BIG number but either way. I still think it would be the way to go though. Not to mention...it just spells S-L-E-E-P-E-R better than anything else, no chrome, black mufflers, just perfect! Oh yea did I mention the sound

 

50 mm= 2 inches exactly according to this.

 

In all truth, it's not "EXACTLY" 2 inches, but damn close.

 

I have a 13B TII S4 I have 3" from the turbo back to a apexi cat then a 3 1/4" from there to a big barrel turbo muffler (like 7" with 5" tip) Sounds sweet, who would want to quite the sound of a roatary anyway? Mine sounds sweet when it comes on to boost at 3 grand, but f*cks with peoples voices trying to talk when sitting in the back.....LOL