Magnaflow Muffler Weld-In

[mowrer7]

I picked up a new Magnaflow 14259 18" Muffler (same as 12259, just polished) off craigslist & just got back from installing it on my 2016 GMC Yukon SLT. I did have them delete the flapper valve, but I left the resonator in fear of drone from the straight thru muffler. My plan was the 12289 24" like NorCal offers, but I got too good of deal on the 18". It's definitely deeper than stock, but not loud. I did notice it doesn't seem to go into V4 mode on the interstate (75mph) unless I tap the brake to turn off the cruise. I wonder if the flapper valve creates back pressure (or something) that helps switch it from V8 to V4? Has anyone else removed their flapper and noticed this?

Keywords: 2015 Chevy Tahoe 5.3L flapper delete

 

[mowrer7]

Sound clip added.

 

[Tommyb80]

Sounds good. Nice Fuel wheels also! I'm running the Coupler's on my F350. Great looking wheel for the price.

 

[vishnu619]

I did a straight through muffler on mine also. I noticed it going into V4 mode more actually. I also already had a blackbear tune on it and need to have it adjusted for the muffler. Should make a difference.

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