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Discussion Starter · #1 ·
I posted a thread on this but it was with a different issue. And I apologise if this is the wrong section but I could not find a section for exhaust.

I have the MBRP turboback catless exhaust system. I have had major headaces with this thing and I'm about to just buy a whole new catback and be done. Maybe the roush idk yet.

But, first off I took the muffler off and it sounded perfect. Then I put the catless down pipe on after a few months and got a terrible trumpet sound anytime I stepped on the throttle so I put the muffler back on. Well dummy me and my quest for screwing myself over thought it needed to be louder again so this time I removed the resonator.

Well this time it's not so bad. I don't have the annoying trumpet sound like I did with the muffler delete but I screwed up welding a pipe back into place and I was off half an inch on the angle so the elbow is pointing down a little bit and it rubs on the heat shield AND the little rubber bracket for the downpipe is ripped. But I can take care of those with a pry bar.

The issue I have is around 2750 -3250 rpms the drone is terrible. Not trumpet drone just normal drone and it makes driving on the highway around 75mph unbearable. I drove from Hendersonville NC to Knoxville TN this weekend (bout 2 hour drive) and I felt like my ears were bleeding. Now when it's at lower rpms it's barely noticeable and the difference is like night and day.

I've been reading some about welding a capped off pipe or chamber at a 90° or so degree angle to help eliminate drone but all I have is an old cherry bomb.

I was planning on removing the axleback part and welding the glasspack into the stream and weld it to the hanger bar and cap it off. Anyone have any science degree in exhaust and resonance that can chime in and help fix my dumbass mistakes.

I just remembered why I did it. I wanted to hear the turbo more and I do it's really loud and I love it but I'm paying the price with the drone. Who stupid can I be.

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Discussion Starter · #5 ·
Alright I’m just trying to find the perfect catback with the catless dp thank you


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I know the MBRP is a common choice and it sounds pretty good with the cat

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If you get a whole new system, Thermal R&D has a rather unique setup with a Hertzian (I think that's what it's called?) resonator that will cancel all your drone, which is what you described with the 90deg pipe. I love the tip on it too. I ended up with a used MBRP with a magnaflow resonator welded in place of the MBRP one. I haven't installed it yet, but the previous owner (catless dp) said his droned a little and that's why he added the MF and that was fine until he went big turbo, then it started to drone and he got Milltek.
 

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The dual resonator MBRP system with a catless that I have has literally no drone after some adjustments for fitment so it doesn't rub anywhere. I'm VERY sensitive to drone and HATE it. If I feel or hear a resonance I get a headache and since I commute 62 miles a day for work that was a no-go. When I read posts like this I immediately wonder if the exhaust is making contact to metal somewhere and vibrating because my exhaust isn't audible at all with music on below 3k rpm if I don't build boost in the morning. Below 1psi you can't tell it isn't stock with music...WITH BOOST yeah it's loud but it's supposed to be and it sounds awesome. Cruising at 75 at -4psi of boost you can't hear my exhaust other than a gentle hum to tell it's there with moderate volume music playing. Adding a Magnaflow performance muffler in place of one of the resonators makes it even more whisper quiet that I've heard...but I would never want it to be THAT quiet.

The only way I can intentionally make my car drone is by going like 70 in 6th gear and building 1-3psi of boost. Then, yeah it does a little. Or when I'm building boost slightly going up a hill at a steady rate...then yeah it drones a little...but it's 3" piping. At a cruise, no drone. I'd be checking to see if it's rubbing.
 

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Discussion Starter · #8 ·
If you get a whole new system, Thermal R&D has a rather unique setup with a Hertzian (I think that's what it's called?) resonator that will cancel all your drone, which is what you described with the 90deg pipe. I love the tip on it too. I ended up with a used MBRP with a magnaflow resonator welded in place of the MBRP one. I haven't installed it yet, but the previous owner (catless dp) said his droned a little and that's why he added the MF and that was fine until he went big turbo, then it started to drone and he got Milltek.
I'll check them out thanks

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Discussion Starter · #9 ·
The dual resonator MBRP system with a catless that I have has literally no drone after some adjustments for fitment so it doesn't rub anywhere. I'm VERY sensitive to drone and HATE it. If I feel or hear a resonance I get a headache and since I commute 62 miles a day for work that was a no-go. When I read posts like this I immediately wonder if the exhaust is making contact to metal somewhere and vibrating because my exhaust isn't audible at all with music on below 3k rpm if I don't build boost in the morning. Below 1psi you can't tell it isn't stock with music...WITH BOOST yeah it's loud but it's supposed to be and it sounds awesome. Cruising at 75 at -4psi of boost you can't hear my exhaust other than a gentle hum to tell it's there with moderate volume music playing. Adding a Magnaflow performance muffler in place of one of the resonators makes it even more whisper quiet that I've heard...but I would never want it to be THAT quiet.

The only way I can intentionally make my car drone is by going like 70 in 6th gear and building 1-3psi of boost. Then, yeah it does a little. Or when I'm building boost slightly going up a hill at a steady rate...then yeah it drones a little...but it's 3" piping. At a cruise, no drone. I'd be checking to see if it's rubbing.
Man thanks for the reply and in fact it is rubbing on the rear axle. I noticed it got louder on my trip to TN and on the way back it was unbearable and now I hear squeaking when I let out the clutch and vibrating on the heat shield too. I'll check it out and keep ya posted.

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Man thanks for the reply and in fact it is rubbing on the rear axle. I noticed it got louder on my trip to TN and on the way back it was unbearable and now I hear squeaking when I let out the clutch and vibrating on the heat shield too. I'll check it out and keep ya posted.

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Yup it commonly rubs there. Do you have Cobb hangers? If not, consider them. That hanger sucks closest to that point.

Edit: Rubbing and causing vibration definitely causes a very noticeable noise. It's a loud and very annoying noise.
 

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Discussion Starter · #11 ·
I do not have those hangers. I didn't know I could even get some lol Man you might have just saved me a lot of money thanks

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I do not have those hangers. I didn't know I could even get some lol Man you might have just saved me a lot of money thanks

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Sure thing man! Hopeful that does the trick! Let us know what the result is for sure. I definitely think it'll make at least an improvement. I love my MBRP and I know for a fact it CAN have drone but it's almost always related to fitment that I've seen.
 

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Discussion Starter · #13 ·
I forgot to update. So the hanger bar over the axle was touching the plate. I bent it down and cut the end off and put a rubber hanger on. It made a difference but it's minimal. The downpipe is still rubbing so I will have to order a new bracket. Unfortunately only one company makes them and they are about $90 so it's sort of a monopoly with that piece. I did some more interwebs searching and found some sound deadening material to put down under the rear seats and back spare cover. The person that wrote a post about it apparently had straight pipe all the way through and it quieted down so much it "sounded stock" to him, I doubt it. I'll order it next paycheck hopefully and see if that helps. If not I'll just save up for another MBRP catback or maybe go with miltek and leave it bee.

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