[SloCal]

Bit of an interesting situation. I bought a used mbrp street series catback on eBay that had a few scratches and dents but fitment was fine. Just got it installed today after a crazy week and initial startup was really underwhelming. Revving it was the same or quieter than npp stock. I had secondary cats deleted in both setups.

The idle sound isn’t anything close to what I’ve heard in videos of other mbrp setups. And the whole system just sounds so weird with no v8 shriek it’s like a f150 with a magnaflow.

Drove it home and the drone was simply unbelievable. I’ve had other performance cars with muffler deletes but this was unreal. It almost sounds like only half the exhaust is coming out the back and the rest is coming out randomly from under the car. Drove back across LA to shop who put their heads under the car when I revved it and said they didn’t hear the rattle or air puffs characteristic of leaks which is true. Took it to another shop who said it just sounded like turbulent air or something didn’t hear leaks.

So I’ve now taken friends around in it and listened on the side of the road to it. It sounds extremely deep and weird like a ****ed up ls3 with headers and it is quieter all the way up top than npp. The drone at all rpms is simply unbelievable and the downshifts sounds like a dodge v6 with. A muffler delete.

All this sounds like some kind of major leak or something but am looking for advice before I have to pay another 200$ to get npp put back on and pay another $100 to ship it back and pay the 20% restocking fee and end up out 600$ just to have the same setup I started with

Any help GREATLY appreciated. Thanks

[badass_lt1]

I've never heard the street series in person before only the race series. The street series is supposed to be much quieter since it actually has mufflers instead of just the straights w/ j-pipes Maybe you should've opted for the race catback instead?

[SloCal]

No it’s not a matter of the exhaust it’s that the whole thing is so****ed you can’t even think straight and the sound isn’t coming out the mufflers like it should sound in videos or even like stock npp. I’m trying to figure out if the exhaust guys were wrong and it’s a big gap in the piping somewhere or if it’s something else

[badass_lt1]

Hmm that's strange if the muffler guys couldn't pinpoint a leak anywhere. Try taking it to another muffler shop. Do you have any soundclips?

[SloCal]

This level of drone doesn’t convey on the phone. It’s just migraines and seat vibrations. There’s no specific leak tick or rattle or air sound it just sounds like clearly it’s not all getting out the back or something is severely wrong. It’s like a 99 civic with a fart can drone level

I can try to get videos but the sound out the back is truck like with no high end rasp or anything just sounds like shut and way quieter than stock

[Mdell2]

Get rid of it asap. I have noticed that the Camaro is not loud even with good aftermarket exhaust compared to Dodges and Mustangs. I have Flowmaster Super 10's (axel back) and it's deeper but not much louder. It's sounds great but just not that loud unless I'm really on it.

[badass_lt1]

Sorry to hear that :(. Tbh youre the first person I've seen to get the street version rather than the race. I have the MBRP race and there's no drone to what your describing. If there's truly no leak, maybe that's just how the street version sounds like. If you have a video, I would love to hear it though.

[SloCal]

Having trouble uploading from my phone.

It’s almost as if 80% of the noise from the exhaust is from vibration or like something else. If you go near the tips there’s a small amount of noise but the rest seems to emanate from under the back end even tho I put a piece of paper near the slip fit connections and it doesn’t react. It isles like a truck not like npp did or any of your exhausts. J am working on getting videos of the drone. I don’t know why all noise is escaping in such a weird way it almost sounds like my friends XFRs cutouts under the cabin but way less clear in sound.

I’m wondering if it’s the dented piping or just totally incorrect installation. It sounds like it should be loud and is just getting ****ed up somwhere

[chaospiece]

That is odd. Since it's street maybe the muffle material is creating turbulence in the system . I didnt even know there was a street version.

[SJFGTO]

If there was a significant leak or exhaust restriction (broken baffle or packing) in a muffler for example you would likely get a CEL.

[SloCal]

Schedule to go to another shop tomorrow. I guess the question is since no one else has this exhaust is it caused by a shit exhaust muffler system with turbulent air or is it the damage to the piping hurting resonance (leaning towards no) or is there a big gap and that would explain why all the noise is escaping upstream as just humming and vibration rather than out the tailpipes?

I don’t want to pay another shop to try to fix welds or reinstall just to then figure out the actual exhaust is just shit and then pay yet again to get trusty npp put back on and then ship this thing back with some bullsjit restocking fee.

Wondering if anyone has ever had this

For reference when I was a kid with my first car I did a washer mod like an idiot to induce an exhaust leak that made my Kia sound loud. This sounds very similar to that so maybe it’s turbulent air like the shop said or maybe it’s not set up right but turbulent air seems weird given that this is exhaustis the less droning version of the race and yet has excessive drone

[SloCal]

This is what the damage looks like. First exhaust shop was certain it would cause no issues or any flow or sound trouble. Opinions?

[badass_lt1]

Hard to tell from the pic but it just looks like alot of scrape damage. I don't see how that should affect the sound drastically at all. Maybe sell it and get the race catback instead? Tbh hearing the videos from MBRP, the street catback doesn't sound good at all.

[SloCal]

When I looked at it before putting it on that area withcdamage had like a 1.5” diameter vs 3” everywhere else because of the significant dent. They’re charging me a restocking fee and shipping return so I’m trying to figure out this one