Lauren Posted June 2, 2016 Report Share Posted June 2, 2016 I just had my s4 exhaust installed today and I'm going nuts driving my car. Between 1100-2600 rpm the drone and loudness is driving me crazy. About 3k rpm there is zero cabin noise. There is a spot where the pipe is super close to the spare tire well which I think is amplifying the interior cabin noise. It isn't to loud if you are outside the car but inside its stupid loud. No way I can take my little girls in the car. Is there a good exhaust shop that can fix this? Is there a different muffler or resonator that can fix it. Please halp Quote Link to comment Share on other sites More sharing options...
jeffro Posted June 2, 2016 Report Share Posted June 2, 2016 Puts loud exhaust on car, complains when loud. The buster. Quote Link to comment Share on other sites More sharing options...
Not Brian Posted June 2, 2016 Report Share Posted June 2, 2016 Call John Moore at Moorespeed Performance (614) 563-3878 They have gear to analyze exhaust sound and install new piping in the correct section(s) or otherwise fix whatever is wrong to lower the drone. Quote Link to comment Share on other sites More sharing options...
cstmg8 Posted June 2, 2016 Report Share Posted June 2, 2016 Helmholtz resonators. They are popular on the G8 exhausts also, due to drone with the AFM. You can even make them at home pretty easily. Some call them "j-pipes". Quote Link to comment Share on other sites More sharing options...
TTQ B4U Posted June 2, 2016 Report Share Posted June 2, 2016 Call John Moore at Moorespeed Performance (614) 563-3878 They have gear to analyze exhaust sound and install new piping in the correct section(s) or otherwise fix whatever is wrong to lower the drone. Sounds pretty cool...pun intended. Am considering the install of an x-pipe or something to offer a nice lower tone but don't want any drone in the cabin. Local friend that was at the track day is getting something done in a week or so and will listen to his. Anything aftermarket for this platform is over the top crazy expensive. Quote Link to comment Share on other sites More sharing options...
zeitgeist57 Posted June 2, 2016 Report Share Posted June 2, 2016 Helmholtz resonators. They are popular on the G8 exhausts also, due to drone with the AFM. Some call them "j-pipes". +1. Can be added relatively easily to an existing system. Possibly something wrong with the S4 exhaust? Hack previous owner gutted muffler or some of the baffles broke off? Might not be enough of a "rattle" but could provide vibration at certain resonances to create a massive drone. Quote Link to comment Share on other sites More sharing options...
Gergwheel1647545492 Posted June 2, 2016 Report Share Posted June 2, 2016 Puts loud exhaust on car, complains when loud. The buster. +1 Quote Link to comment Share on other sites More sharing options...
zeitgeist57 Posted June 2, 2016 Report Share Posted June 2, 2016 If it's anything like the Apexcone SS exhaust I put on my widdle 1.8L BMW, there could be an exhaust leak...split at a factory weld/flexpipe, or a gasket hasn't sealed properly. Same exact symptoms: I had a weld on the 4-2-1 header collector crack. Re-tacked the weld, resonance went away. Quote Link to comment Share on other sites More sharing options...
Lauren Posted June 2, 2016 Author Report Share Posted June 2, 2016 No leaks. I had the car on a lift and went from flex pipe to tail pipe looking for leaks. I k ow it isn't a leak. The thing is awesome above 2800-3000 rpm. No cabin noise at all. It's just the low end that's almost unbearable. Perhaps the muffler is bad or broken because this system is t known to drone at all. Will check out more speed and see if They can fix it Quote Link to comment Share on other sites More sharing options...
kirks5oh Posted June 2, 2016 Report Share Posted June 2, 2016 Just always keep it above 3000rpms at all times?? Or don't buy aftermarket exhaust systems?? Quote Link to comment Share on other sites More sharing options...
Alfa Turbo Posted June 2, 2016 Report Share Posted June 2, 2016 Call John Moore at Moorespeed Performance (614) 563-3878 They have gear to analyze exhaust sound and install new piping in the correct section(s) or otherwise fix whatever is wrong to lower the drone. John made a 3" exhaust for my car and it droned from 2200-2600 rpm. A little research on the web and I found the calculation to develop an inverse wave at that RPM, turned out to be 40". John added a 40" j-pipe to the exhaust and no more drone. https://goo.gl/photos/2Uigc7vmMhra7sHB6 Quote Link to comment Share on other sites More sharing options...
99StockGT Posted June 2, 2016 Report Share Posted June 2, 2016 Hopefully Moorespeed can get you taken care of, if not, feel free to get in touch I'm sure I know some people who could help! Quote Link to comment Share on other sites More sharing options...
Dafunk13 Posted June 2, 2016 Report Share Posted June 2, 2016 J-pipe fix for sure. Quote Link to comment Share on other sites More sharing options...
coltboostin Posted June 5, 2016 Report Share Posted June 5, 2016 John made a 3" exhaust for my car and it droned from 2200-2600 rpm. A little research on the web and I found the calculation to develop an inverse wave at that RPM, turned out to be 40". John added a 40" j-pipe to the exhaust and no more drone. https://goo.gl/photos/2Uigc7vmMhra7sHB6 Thats fuck'in fancy! Quote Link to comment Share on other sites More sharing options...
buelliganx1 Posted June 5, 2016 Report Share Posted June 5, 2016 Is that j pipe capped at the end or is it plumbed back into the system in the back Quote Link to comment Share on other sites More sharing options...
cstmg8 Posted June 5, 2016 Report Share Posted June 5, 2016 Is that j pipe capped at the end or is it plumbed back into the system in the back Capped, otherwise the specific length to frequency ratio wouldn't work. Basically it bounces back the opposite frequency of your drone, "absorbing" it. Quote Link to comment Share on other sites More sharing options...
Alfa Turbo Posted June 5, 2016 Report Share Posted June 5, 2016 Capped, otherwise the specific length to frequency ratio wouldn't work. Basically it bounces back the opposite frequency of your drone, "absorbing" it. To be "that guy"... you are technically creating a length of pipe that is 1/4 the length of the standing sound wave that is creating the resonant "drone". 1/4 since the wave has to travel there and back making it half of the length thus cancelling the sound wave at that frequency. Were you to design it so it were movable like a tuba you could tune it for several frequencies if you had them. In my case the additional pipe was 40" to offset a 160" or 13 foot standing wave. Kinda crazy to think the standing wave is about the same length of the car. FWIW, the car is also quieter at idle. Quote Link to comment Share on other sites More sharing options...
cstmg8 Posted June 5, 2016 Report Share Posted June 5, 2016 To be "that guy"... you are technically creating a length of pipe that is 1/4 the length of the standing sound wave that is creating the resonant "drone". 1/4 since the wave has to travel there and back making it half of the length thus cancelling the sound wave at that frequency. Were you to design it so it were movable like a tuba you could tune it for several frequencies if you had them. In my case the additional pipe was 40" to offset a 160" or 13 foot standing wave. Kinda crazy to think the standing wave is about the same length of the car. FWIW, the car is also quieter at idle. Yeah, the adjustable tubes are what's popular in the G8 world. Quote Link to comment Share on other sites More sharing options...
TTQ B4U Posted June 5, 2016 Report Share Posted June 5, 2016 Call John Moore at Moorespeed Performance (614) 563-3878 going to hear a friends S4 with a Magnaflow X-Pipe installed in place of the large turd of a resonator he had removed. From the video posted it sounds pretty good. If so, John will likely be doing the same on mine so I can finally ditch the soundakator fake noise. I pulled the fuse and disabled it but then the damn car is too quiet. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 6, 2016 Report Share Posted June 6, 2016 anyone have pictures of this j-pipe fix? This is one of the main reasons I sold my old fox body and REFUSE to touch the factory exhaust on any performance car anymore!! I put the quietest mufflers I could on that old mustang (tried 3 types) and it was still brain shaking. Quote Link to comment Share on other sites More sharing options...
TTQ B4U Posted June 6, 2016 Report Share Posted June 6, 2016 This is one of the main reasons I sold my old fox body and REFUSE to touch the factory exhaust on any performance car anymore!! I put the quietest mufflers I could on that old mustang (tried 3 types) and it was still brain shaking. I'm with you and maybe I'm just getting old. Passing on any sound mods on mine. The ride yesterday was fun and it does sound good on drive-by's but inside even just an X-Pipe in place of a resonator turned his quiet cabin of a German Sedan into an annoyingly loud sedan that is not representative of such a car. He likes it and that's all that matters. I'll pass. Especially given it adds no performance gains. Quote Link to comment Share on other sites More sharing options...
zeitgeist57 Posted June 6, 2016 Report Share Posted June 6, 2016 I'm with you and maybe I'm just getting old. Passing on any sound mods on mine. The ride yesterday was fun and it does sound good on drive-by's but inside even just an X-Pipe in place of a resonator turned his quiet cabin of a German Sedan into an annoyingly loud sedan that is not representative of such a car. He likes it and that's all that matters. I'll pass. Especially given it adds no performance gains. Tim, I'm with you. I drove the BMW to Cleveland/Akron/Zanesville/Youngstown/Mansfield over the 2 months my V was in the shop, and I ended up getting earplugs The V has a cat-back Magnaflow and that's about as loud as I'll get on a performance DD. I still love a loud ride, but finding myself appreciating a quieter ride when I'm 3+ hrs on the road in a day! Quote Link to comment Share on other sites More sharing options...
buelliganx1 Posted June 6, 2016 Report Share Posted June 6, 2016 To be "that guy"... you are technically creating a length of pipe that is 1/4 the length of the standing sound wave that is creating the resonant "drone". 1/4 since the wave has to travel there and back making it half of the length thus cancelling the sound wave at that frequency. Were you to design it so it were movable like a tuba you could tune it for several frequencies if you had them. In my case the additional pipe was 40" to offset a 160" or 13 foot standing wave. Kinda crazy to think the standing wave is about the same length of the car. FWIW, the car is also quieter at idle. You just gave me a science boner. But seriously that's some pretty interesting shit and I've never seen that done before. Always like learning something new. Quote Link to comment Share on other sites More sharing options...
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