As I look at the stock exhaust, I notice the two downflow pipes, two cats, and two pipes into a resonator box, with one outlet. I am purchasing the RD Sport Quad Exhaust. I didn't not want a fake quad, nor did I want a HP loss associated with the cat-back options. Based on what I read, the RDSport Quad will not lose HP and will give me a true quad option. I've listened to the sound clips and think I may prefer a little quieter car. If I inserted a bullet resonator on each pipe, would that quiet it down a little? If so, should the resonator be installed closer to the cats, or downstream closer to the mufflers?

If this turns out to be the option, does anyone have an idea where I can get resonators that fit the RD Sport setup?

Thanks!

 

another question is.... by putting the bullet resonator will that mess with the flow of the exhaust hence losing horsepower!

to my understanding, that would, but that would be a RD sport question, maybe they can run the numbers! no point of spending on a exhaust if its not making power for you.

 

Buller... Buller... Buller... Can anyone add anything to this one???

 

I removed all resonators with my RD quads. Sounds great, and no droning. I have a 550, so things will differ with yours.

 

The RDSport exhaust is actually not that loud but I do understand that's a subjective remark. I knew a couple members on this forum with the RDSport quads on their 545 and didn't think it was that loud. Just nice and deep. Even the complete system on my M5 with headers is not that loud at all compared to other exhausts I've heard on other M5s that don't even have the headers.

As for adding the resonators, unfortunately I don't know the answer to your questions but I think a muffler shop can probably give you an opinion. Or maybe PM RPIpower and ask Eloy about adding resonators to exhausts in general, if you don't get an answer back from RDSport in a timely manner.

 

Stick with what RD Sport has already. It's the rear mufler that is responsible for much of the drone, so bullet blankets will not help you much. I have a total of 5 resonators, 2 oe, 2 blanks, and the center box. Additionally, I have the turbo tubes, which is like the OE mufflers without absorptive materials inside. It is a nice and noticably louder than stock sound, will not drone at any rpm, but it won't wake up the neighbors or drive my wife crazy. It awesome every morning when I drive into a parking garage. At rpms of 2200 and higher, it is a tad louder at WOT. The butt dyno does not experience any loss at low rpm like the straight through magnaflows I had before.

 

I have purchased the RD Sport exhaust from EuroRev. I haven't received it yet, but it will be shipped with the rest of my new parts.

I just had an interesting conversation with an exhaust "expert" at a local performance shop. He likes the RD Sport exhaust and said that it will sound great, and not too loud as is. He noted that the RD Sport exhaust that I'm purchasing was designed for the v8, and later the retrofit pipes were added as an option to make it work on the twin turbo. He doesn't like the idea of the x-pipe being part of the exhaust on a twin turbo and said it's completely unnecessary. On a turbo, he would rather see two straight thru exhausts... cats, pipe, muffler, & tips.

He asked me what the purpose of the x-pipe for my configuration would be... I don't know... Does anyone have a reason of why this is part of the engineering?