[travislambert]

I'm installing a Magnuson 2650 on my '17 ZL1. The car is used exclusively for the road course, and I don't want the cats blowing up or clogging due to higher boost and race oil. To ensure that doesn't happen, I plan to remove the catalytic converters as part of the install. (I'm fully aware of how the exhaust will smell, and I'm not worried about that.)

What I'm looking for is a cat delete solution that maintains the factory exhaust manifolds and suitcase muffler. Ideally this solution would include something to avoid an obnoxiously loud exhaust as I would like to run at NCM and possibly other tracks with decibel restrictions.

I've considered these pipes from NEP, but the sound is the primary concern here. I'm afraid the end result will be too loud for some tracks.
http://www.neweraperformanceparts.co...ete-pipes.html

Another option would be to incorporate these primary cat deletes into a solution.
http://bulletperf.com/chevrolet-camaro-2016-cat-delete

With the primary delete pipes in place, I was thinking the factory secondaries could be removed and replaced with something higher flowing that would soften the sound. I know there are some tiny performance mufflers that might work here, but I don't want anything with mesh or screens blocking the flow. Otherwise, I'd just keep the factory secondaries in place.

Thoughts?

[IneedAZ]

Would you consider running a left and right resonator in place of the converters?

[TMS]

I currently run the NEP pipes with primary and secondary cats deleted, factory manifolds (I ported on the outlet side) with the factory suitcase muffler. It has basically been an evolution of different exhaust configurations. I first started with a cat-back (secondary delete) Borla S-Type exhaust. Eventually, as my power numbers climbed (after more mods), I was afraid of burning out my primary CATs. I removed them (running 14 pounds boost at peak) and put in resonators before the X-Pipe and it was too loud. Then I put the factory suitcase muffler back on. I now have the perfect volume. I took decibel readings for each of these various evolutions. You can check out the readings here if you want. https://www.camaro6.com/forums/showthread.php?t=559526

Hope it helps.

Good luck.

[travislambert]

Originally Posted by IneedAZ

Would you consider running a left and right resonator in place of the converters?

Yeah, that's basically what I'm thinking. I just don't want the exhaust to have to flow through a fine screen that I might have a problem with later.

[IneedAZ]

Originally Posted by travislambert

Yeah, that's basically what I'm thinking. I just don't want the exhaust to have to flow through a fine screen that I might have problem with later.

Like you, i too am thinking of doing the 2650 and I will throw ARH long tubes and exhaust going into the stock muffler. To tame the noise down, will add some resonators in place of the converters.

[travislambert]

Originally Posted by TMS

I currently run the NEP pipes with primary and secondary cats deleted, factory manifolds (I ported on the outlet side) with the factory suitcase muffler. It has basically been an evolution of different exhaust configurations. I first started with a cat-back (secondary delete) Borla S-Type exhaust. Eventually, as my power numbers climbed (after more mods), I was afraid of burning out my primary CATs. I removed them (running 14 pounds boost at peak) and put in resonators before the X-Pipe and it was too loud. Then I put the factory suitcase muffler back on. I now have the perfect volume. I took decibel readings for each of these various evolutions. You can check out the readings here if you want. https://www.camaro6.com/forums/showthread.php?t=559526

Hope it helps.

Good luck.

Thanks for this great information!

So are you still running the Vibrant resonators? I see other changes were added at the same time, but do you think the resonators helped?

[TMS]

Originally Posted by travislambert

Thanks for this great information!

So are you still running the Vibrant resonators? I see other changes were added at the same time, but do you think the resonators helped?

Yes, I am still running the Vibrant resonators. "Do they help?" - It's a fair question. Looking back, I wish I added the resonators just by themselves and then took sound measurements just to have the data points. Honestly, I don't think they do much of anything in terms of volume. When the suitcase went back on, that was dramatic.

Aside from this, I have read reports of droning when people remove primary and secondary cats. I think the resonators definitely help with drone. I don't have any drone that I can detect. I think this is the value-add for the resonators. If I had a do over, I think I would have bought the longer resonators which might have had more impact on volume (but this is just a guess). The sound is great but, depending on the track it may still exceed noise limits. My conclusion is that this current setup seems to be about 5 dB louder than full factory stock.

[travislambert]

So it sounds like the resonators certainly add value. In addition to vibrant, here are a couple of other options I've found so far. I don't know if they're better or worse though.
http://www.slponline.com/product/310...ator-Each.html
https://www.borla.com/products/crate...t__400939.html

It looks like vibrant also offers a race muffler:
https://vibrantperformance.com/catal...roducts_id=271

Maybe a resonator / muffler combo in place of the secondary cats?

[TMS]

My bet is that any of the resonators will yield similar results (assumes they all follow the same basic design principle). I think the idea of that race muffler is intriguing. That could do it. However, I would check the design to make sure it does not contain glass or other packing material that will blow out over time. I know Flowmaster has a laminar flow (conical) design and they work great. I have them on another car’s sidepipes and they are awesome. But they don’t really have them in compact packaging that would fit (at least I don’t think so).

Following your thread to see how this turns out. Intrigued.

[travislambert]

Originally Posted by TMS

My bet is that any of the resonators will yield similar results (assumes they all follow the same basic design principle). I think the idea of that race muffler is intriguing. That could do it. However, I would check the design to make sure it does not contain glass or other packing material that will blow out over time. I know Flowmaster has a laminar flow (conical) design and they work great. I have them on another car’s sidepipes and they are awesome. But they don’t really have them in compact packaging that would fit (at least I don’t think so).

Following your thread to see how this turns out. Intrigued.

Funny, I was just looking at the flowmaster race mufflers as you posted this. I think there is potential, but I'm not certain there's room for both resonators and mufflers.

https://www.holley.com/products/exha.../parts/8430408

[Sakudog]

Ok, very interesting post OP, simply because I too have purchased a 2650R and am in the exact same boat. Header's with NPP is way, way, way too loud to enjoy and the rwhp gains just don't align with the cost of LTs for me so I was thinking about 'off road' pipes as you are but still worried about sound quality and volume.

The resonators can go into the OEM exhaust in several places, but one idea I've seen work well in the CTS-V2 world is adding a x-flow muffler where the X-pipe is located. Packaging, being the biggest challenge.

You know, at this point I'm really surprised a LT header offering with built in mufflers isn't offered because it seems like everyone wants headers, until they daily the car and it's too loud or get a Black Flag because they are over 100db.

https://www.carid.com/gibson/cft-sup...specifications


If I was to have a set of resonators added to the car in the primary pat location, I'd probably look to have the fabricator put these two in that location.

https://vibrantperformance.com/catal...01e3cbcf1aa7dd

[Sakudog]

Originally Posted by TMS

My bet is that any of the resonators will yield similar results (assumes they all follow the same basic design principle). I think the idea of that race muffler is intriguing. That could do it. However, I would check the design to make sure it does not contain glass or other packing material that will blow out over time. I know Flowmaster has a laminar flow (conical) design and they work great. I have them on another car’s sidepipes and they are awesome. But they don’t really have them in compact packaging that would fit (at least I don’t think so).

Following your thread to see how this turns out. Intrigued.

Do you have any video you can share? Driving?

I appreciate you sharing the information.

[Dixie ZL1]

I thinking that removing the primaries only might the the solution. The secondaries and suitcase muffler will manage sound and a primary CAT delete will be safe with boost.

[travislambert]

Originally Posted by Dixie ZL1

I thinking that removing the primaries only might the the solution. The secondaries and suitcase muffler will manage sound and a primary CAT delete will be safe with boost.

I have been told by a reputable source that even the secondaries won't hold to heavy track use with the 2650. They estimated 10-15 hours of track use before problems start to emerge. Otherwise, I'd be right there with you. It seems like an obvious solution, and it may work well for some, but my car is used exclusively for track. I'd hit 10-15 hours in a couple of months.