The 1947 - Present Chevrolet & GMC Truck Message Board Network

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The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)

- LSx Swaps (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=206)

- - Exhaust/Mufflers (https://67-72chevytrucks.com/vboard/showthread.php?t=818770)

nsb29

03-18-2021 08:37 AM

Re: Exhaust/Mufflers

so basically it’s a small glass pacts thanks sounds like a solution

Gregski

03-20-2021 02:27 AM

Re: Exhaust/Mufflers

just wanted to share some pics of me ditching my DroneMasters and going with some Magnaflows, honestly still loud without cats, these were hacked out of some GTO

rig is a 4.8L LR4

https://67-72chevytrucks.com/vboard/...1&d=1473225951

https://67-72chevytrucks.com/vboard/...1&d=1473225976

https://67-72chevytrucks.com/vboard/...1&d=1473226106

I built my dual exhaust out of stock Tahoe and Suburban exhaust pieces from Pick N Pull by reversing the passenger side to the driver side, here is a link to the build post if anyone wants to take a peak

https://67-72chevytrucks.com/vboard/...postcount=6059

Steve Cole

03-22-2021 03:53 PM

Re: Exhaust/Mufflers

3 Attachment(s)

Quote:

Originally Posted by nsb29 (Post 8895238)

I have the cast manifold that came with the motor which is from a Pontiac G8 I believe similar to the Camaro cast manifolds from there is 2 1/2 inch exhaust back to the mufflers and then exit behind the rear wheels I did not use an H Or X pipe driving down the highway it really isn’t that loud but going through the gears it’s louder than I wanted I am considering installing two small glass packs behind the mufflers in a straight area about a foot and a half from the end I also wondered if it was because I did not install an H or X pipe ????? I also wondered if it was the brand I bought and maybe I should have bought magnaflows but if you’re having the same problem that’s obviously not it if you figure out something before I do post it I’ll do the same

Here is how mine is routed. Are your mufflers this far back? I am using 2.5" pipe as well.Attachment 2090869

Attachment 2090870

Attachment 2090872

Gregski

03-23-2021 02:10 AM

Re: Exhaust/Mufflers

Quote:

Originally Posted by Steve Cole (Post 8897847)

Here is how mine is routed. Are your mufflers this far back? I am using 2.5" pipe as well.Attachment 2090869

Attachment 2090870

Attachment 2090872

beautiful exhaust, and I don't want to be a dingleberry but I would question your O2 sensor placement you want them pointing down to avoid moisture and sediment not up, I know sometimes there is interference and we have to get creative

Steve Cole

03-23-2021 12:13 PM

Re: Exhaust/Mufflers

Gregski,

You are talking about the part that goes inside the pipe right?

Gregski

03-23-2021 12:52 PM

Re: Exhaust/Mufflers

2 Attachment(s)

Quote:

Originally Posted by Steve Cole (Post 8898276)

Gregski,

You are talking about the part that goes inside the pipe right?

yes, and where the bungs are welded, I have circled them here in this pic

NOTE: The oxygen sensor should be mounted in such a way that the condensation in the exhaust tubing will not enter the sensor. Mount the O2 sensor in the upper half of the exhaust tubing, with the angle “x”, shown above, being greater than 10°. The diagram below indicates that the sensor can be mounted on either side of the exhaust tubing.

Steve Cole

03-23-2021 05:58 PM

Re: Exhaust/Mufflers

Sweet, thanks! That is how the muffler guy had them positioned when I picked it up and I didn’t think twice about it but what you said makes sense. I just realized he screwed me because it is welded now and I can’t rotate the bung!

jweb	03-23-2021 07:06 PM

Re: Exhaust/Mufflers

I have Magnaflows similar to these on my '51 (LS1) and it sounds pretty good.
https://www.magnaflow.com/products/1...rmance-muffler

When I had the exhaust made, they recommended two things.

1: Keep the mufflers close to the headers. They said this would reduce the drone because the further you let the exhaust travel before passing through a muffler the more drone you will have. Due to the sound waves bouncing around in the pipes.

2: Run the pipes all the way to the back. This way, even if it's a little loud it will be further away from you.

Adding a resonator before the muffler may be a good fix for this problem.

Steve Cole

03-24-2021 11:57 AM

Re: Exhaust/Mufflers

Thanks for the info jweb. My issue isn't really drone, it is that it just sounds like crap. I think nsb29 doesn't like the sound of his either.

Steve Cole

03-24-2021 11:59 AM

Re: Exhaust/Mufflers

Quote:

Originally Posted by jweb (Post 8898446)

Jweb, Do you have pics of your exhaust system?

jweb	03-24-2021 12:59 PM

Re: Exhaust/Mufflers

Quote:

Originally Posted by Steve Cole (Post 8898751)

Jweb, Do you have pics of your exhaust system?

No, I don't have any pics. It's fairly simple though. I have an H pipe then the mufflers are near the back of the cab. After that the pipes run to just behind the bumper with turn downs.

I also added electric cut outs but I never use them, it sounds terrible when they're open.

Steve Cole

03-24-2021 01:07 PM

Re: Exhaust/Mufflers

Are you happy with the sound?

I was just on the phone with tech help at Magnaflow. I explained what I had before with my old system and what I have now. He said not having an X or H pipe has a much more significant impact on the sound than muffler placement does. He said the H pipe has a deeper tone and the X pipe has better scavenging. I am going to have an H pipe installed and see how it sounds then.

nsb29

03-24-2021 06:10 PM

Re: Exhaust/Mufflers

Quote:

Originally Posted by Steve Cole (Post 8898750)

Thanks for the info jweb. My issue isn't really drone, it is that it just sounds like crap. I think nsb29 doesn't like the sound of his either.

You got that right
I’m about ready to replace them with a pair of glass packs LMAO

Steve Cole

03-25-2021 08:17 AM

Re: Exhaust/Mufflers

Quote:

Originally Posted by nsb29 (Post 8898926)

You got that right
I’m about ready to replace them with a pair of glass packs LMAO

Before you replace the mufflers, consider installing an X or H pipe. The tech guy at Magnaflow said it would make a huge difference in sound. It is a cheap thing to try too.

nsb29

03-25-2021 05:00 PM

Re: Exhaust/Mufflers

Just kidding around but I am seriously thinking about putting cats or glass packs in front of the mufflers as I do have a lot of straight pipe before the mufflers for the sound to rattle around in as well as An H pipe we put flowmaster 40s on my buddies 64 283 El Camino had a decent sound they advertise their 50s series as quieter I guess the big difference is a 6.0 LS isn’t a 283 with a mild cam

OutlawDrifter

04-22-2021 11:29 AM

Re: Exhaust/Mufflers

H-pipe will give it a deeper sound, X-pipes sound similar to a 2-into-1 exhaust. Both help it sounds "better".

OP, I would suggest 18" bodies if you don't want it super loud. 2.5" exhaust pipe would be plenty, and I would go with an H or X after the transmission/xfer case. Skip the Magnaflow premium, and buy Jones/AP/Cherry Bomb copies. The 5x8x24 would be a great option as well, that would keep it super quiet until you smashed the go pedal.

If you end up with drone, you can use Helmholtz resonators on the tailpipes. @aknovaman, has done some write-ups on it, great guy and very helpful!

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