2014 SS hybrid muffler for PPV

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Navy Lifer
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2014 SS hybrid muffler for PPV

Post by Navy Lifer »

Thanks to Bob (Leadfart) and an SS owner I have made acquaintance of, and with Scott & Alex Walker's effort & skills, a pair of mufflers has been brought together "Frankenstein style", that will be installed on the PPV soon--having to interrupt things for a trip to Omaha to attend a funeral on Friday (Maurice, send me your phone number!).

Pictures tell the story, but in case you aren't aware, the SS muffler is the exact same dimensions as the PPV muffler, as far as the case dimensions and hanger method--the differences are the 90-degree pipe on the inlet (SS has no flange) and the outlet pipe is too short to reach the proper length in relation to the PPV bumper cover.

What we do know is this: on a PPV, the SS muffler definitely provides more sound at the tailpipes than a stock PPV system, however it is NOT as loud as the full production SS system--a more refined sound, rather than brutish. To me, it actually sounds pretty nice--not being as loud as the SS is a plus, IMO, but it's not been tested with full throttle to see what really happens. I'm really wanting to find out what is going to happen in AFM 4-cylinder mode.

This means that the piping in front of the mufflers on the SS has less sound attenuation built in than the PPV piping setup does. Scott had removed his mufflers, as his car was being used for test-fitting of the mufflers you'll see below--the car is not NEARLY as loud with no mufflers as I would expect, nor is it nearly as loud as the SS that donated it's mufflers for this project--the owner was driving the car with the mufflers removed and just the intermediate piping in place--and no tailpipes when I saw it....MUCH louder than Scott's PPV with no mufflers. Realize the SS also has the LS3, with more aggressive camshaft, but I suspect the PPV would be nearly as loud with the rest of the SS piping installed (length adjusted accordingly).

Anyway, here's some pictures, and whatever discussion is stimulated, I'll try to answer, or Scott may comment, too. The pipes are just tacked together at this point, as I'm planning to have them Tig welded--yes, that is a split on the bushing of one muffler where a weld gave way while having a shop expand some of the connection points to be able to put this system together the way I wanted to. Not a big deal, really, once it's welded.
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SS hybrid muffler 2.JPG
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SS muff8.JPG
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elc32955
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Re: 2014 SS hybrid muffler for PPV

Post by elc32955 »

Bill, for this one I think a video is going to need to be made once installed. Youtube or the kind would be a good medium.... :) I've been wondering how this could sound for a while now.

Still, thoughts of servoed cutouts run through my head from time to time... heh heh....

Eric
System Manager and your tour guide for the day. 2015 Caprice w/LFX, former NC DPS staff car. Partial hybrid G8/SS/Camaro SS interior mods, SS MyLink radio upgrade, 2016 Camaro V6 rims, GMPP Malibu chrome exhaust tips, otherwise bone stock for now.
Navy Lifer
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Location: Canton GA

Re: 2014 SS hybrid muffler for PPV

Post by Navy Lifer »

Off with the old.....
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On with the new---much gratitude to Team Walker (Scott and his son Alex) - hard core Chevy guys - for their efforts to bring this to completion.
new muffler1.JPG
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new muffler5.JPG
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Navy Lifer
Administration Staff
Posts: 1724
Joined: Tue Mar 19, 2013 6:30 pm
Location: Canton GA

Re: 2014 SS hybrid muffler for PPV

Post by Navy Lifer »

After a week of experience with the new (2014 SS) mufflers, a few observations.

1. Recently made a trip to Nebraska (before muffler change) and noticed how much more detectible the transition from 8 to 4 cylinder mode has become. Spoke to local GM dealer tech, and he acknowledged that historically the AFM system does become more noticeable in operation with time/mileage. Have to say I'm not a fan of 4-cyl mode, as the difference in drivetrain smoothness when the shift from 4 to 8 cylinders occurs is QUITE apparent.

2. After muffler change, it is quite easy to detect when the car is going between 4 & 8 cylinder mode, which was not the case with stock mufflers. I have never put the AFM status up on display in the DIC to confirm the transition and change in sound. This particular muffler is not "that" problematic, but if the entire system from the SS was on PPV with AFM, I think the 4-cyl mode could be quite annoying.

3. Stopped by an auto shop I do business with on occasion, and there was the back half of a Gen5 Camaro exhaust system sitting there, which had been removed--this system was from an L99 (6.2 with AFM), and it has a spring-loaded flapper valve inline forward of each stock muffler, which is a VERY large "can" that is formed to fit & fill in the whole space on each side--looks more like a washtub, actually. These mufflers have a single outlet.
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If the concept of the Dynomax VT muffler http://www.dynomax.com/mufflers/dynomax-vt-mufflers - with flapper valve - is valid, as far as it's claim of eliminating drone, the flappers on the L99 Camaro are the "fix" to mitigate drone in the Camaro when in 4-cyl mode. Going to keep my eye out for these, as they probably do not have a separate PN from GM--the entire pipe assembly is available as one part, I'm guessing. Someone had to make them, so finding them available separately should be possible.

Point is, I would try them to see what happens to exhaust tone in 4-cyl mode with these mufflers on the car. Eventually the real fix will be to eliminate AFM and it's attendant drone-inducing exhaust pulsing, but until then, I'll pursue the flapper valves to conduct a test.
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