Custom Exhaust

[Siggy Smalls]

Hey all -

 

I don't spend a lot of time on web forums posting but I spend a ton of time researching answers to questions because it's the only place to get real answers. So, whenever I have something that I think would help others, I feel compelled to return the favor. I thought I'd share my exhaust in case anybody was interested (truck is a 2017 crew cab) which sort of mimics the function of the NPP mufflers that came on C6 Corvette Z06's and the muffler bypass. Components were pretty simple and exhaust dumps over the rear axle with a 4" tip:

 

- Removed 3rd cat and everything behind it

- Magnaflow 12641

- DMH 3" electric butterfly valve

- SS 3" cutouts

 

The 12641 is 30" long (body), 6" round, 3" I/O. I chose it because...

 

a) I wanted the muffler to be noticeably quieter when the bypass was closed and this is Magnaflow's longest 3" I/O muffler

b) I needed a round muffler to make room laterally for the bypass pipe

c) Nobody else makes one this long, in this outside diameter, 3" I/O, etc

 

So, if the valve is shut - it's like most 3" catback exhausts (minus the 3rd cat). But if the valve is open, it's essentially straight piped... although a good portion of the exhaust gas still goes through the muffler because either route is straight through before they mate back together. As far as sound... amazing. Better than I expected. I've never been so happy with an exhaust project.

 

When the valve is shut, the muffler is quiet, as desired, and I can tell that it hasn't broken in yet... mild, deep, mellow tone. When the valve is open, it's louder (of course) and the sound and the tone are awesome. I'd assume it's a touch milder than a "true" straight pipe... the only way I can describe it is an "old school" sound. What surprised me most is that I can't hardly hear it inside the cab - valve open - cruising down the road with the windows up. There is no drone, it doesn't invade the cabin, etc.

 

Pictures below. Hope this helps anybody interested. Here is a video:

 

 

[Siggy Smalls]

First pic

[Siggy Smalls]

Second pic

[smrr1]

A bit extreme for a pick up but i can respect the good work. Looks good.

[Siggy Smalls]

Third pic

[Siggy Smalls]

A bit extreme for a pick up but i can respect the good work. Looks good.

 

Thanks man. For what it's worth, I have less money into it than a Magnaflow catback.

[patrick6.2]

That's a awesome setup. I'm going to buy either the Corsa or SLP catback. Been trying to decide which one for like 6 months to get...I don't want to install it until it warms up anyway. Is yours a 5.3 or 6.2? Would love to have a custom exhaust like that, but I want something I can put on quick and easy, great job!

[Siggy Smalls]

That's a awesome setup. I'm going to buy either the Corsa or SLP catback. Been trying to decide which one for like 6 months to get...I don't want to install it until it warms up anyway. Is yours a 5.3 or 6.2? Would love to have a custom exhaust like that, but I want something I can put on quick and easy, great job!

 

It's a 5.3... it wasn't hard. Just call DMH and find a good exhaust shop. The hardest part was wiring the switch.

[Luster]

Very nice exhaust setup. Also, if you don't want to go the parallel pipe route, you can always just install the cutout in front of a stock muffler... super quiet to super loud!

[DLW66]

That's a awesome setup. I'm going to buy either the Corsa or SLP catback. Been trying to decide which one for like 6 months to get...I don't want to install it until it warms up anyway. Is yours a 5.3 or 6.2? Would love to have a custom exhaust like that, but I want something I can put on quick and easy, great job!

I recently installed the SLP catback on my 2017 6.2L Sierra. I like it, super easy install, took about an hour to remove stock exhaust and install the SLP. Sounds good, no drone, a nice tone inside and out.

 

One thing for sure, is you can definitely tell when the AFM kicks in with the louder exhaust where I never noticed it with the over quite stock system. If I was brave enough to risk the warranty, I would for sure disable it with my HPTuners.

 

To the OP, nice job, sounds good. A bit loud for me with cutout open (used them many times for street track cars), but I like the tone with it shut, nice and mellow.

[patrick6.2]

I recently installed the SLP catback on my 2017 6.2L Sierra. I like it, super easy install, took about an hour to remove stock exhaust and install the SLP. Sounds good, no drone, a nice tone inside and out.

 

One thing for sure, is you can definitely tell when the AFM kicks in with the louder exhaust where I never noticed it with the over quite stock system. If I was brave enough to risk the warranty, I would for sure disable it with my HPTuners.

 

To the OP, nice job, sounds good. A bit loud for me with cutout open (used them many times for street track cars), but I like the tone with it shut, nice and mellow.

Thanks for the quick review! I'm leaning towards the SLP, one because my uncle has a camaro full of slp parts, and it is almost half the price of corsa. Only place I can find it on sale is the slp website. Where did you buy yours from?

[DLW66]

Thanks for the quick review! I'm leaning towards the SLP, one because my uncle has a camaro full of slp parts, and it is almost half the price of corsa. Only place I can find it on sale is the slp website. Where did you buy yours from?

Also bought from SLP. Oddly, I think CJ Pony parts is the only other one I saw selling it. They did a nice install video and test drive of it also.

[LongrangeLauber]

Damn that sounds good. I don't think I'd do it to this truck but it makes me miss my old 02 Silverado, I just cut off the muffler and that thing sounded killer

 

Sent from my SM-N920V using Tapatalk

[KARNUT]

I use to have my exhaust shop do something similar. Option one was run a y pipe muffler on one side and a straight pipe one all the way back with turn downs just before the back bumper. The strait side I weld a header flange close it with wing nuts. Or run the straight out in front of the rear tire. On a trip I'd run quiet, local I'd run loud. I don't trust electric cut outs.