14" Magnaflow single in/out review - 5.3L - 6 speed

glendon66 · April 16, 2019

I finally went with a Magnaflow muffler after many hours of watching youtube reviews (while wearing headphones), researching forums and reading as many customers reviews as I could find. It's a tail chasing activity because in reality you won't know if you like something unless you hear it for yourself in-person. I had the Corsa sport system in my shopping cart for a few days but spending a $1,000+ wasn't something I wanted to do.

I decided to go to the local shop and see what he thought I should do based on all the information I had gathered. He suggested a Flowmaster but I was really leaning more towards to the deeper tone of the Magnaflow. He asked if I wanted to go with the 18" and I decided to go with the 14" with a single out with the resonator also being removed. Grand total with install and black exhaust tip was $375 which seems more than fair. For that price I could redo the exhaust 2 more times and be at the price of the Corsa but I will always wonder if I should have just done the Corsa instead. I ended up using the extra money I didn't spend on the Corsa to get a paint correct/ceramic pro 2 year done on my beautiful blue 2017 GMC elevation so it all worked out.

The Review:

It sounds very good. At times it sounds amazing and other times it sounds not so great. Cold start is much louder than I expected but not raspy so it doesn't hurt the ears. At idle you don't hear anything and sitting at a stop light is nice for you and everyone around you. Basic acceleration sounds very good but around the 1600-2100 RPM range (right around the shift points) I get a bit of drone. I never knew what "drone" really meant until now. It's not something I hate but I do find myself trying to avoid that RPM range if people are in the truck because it makes it sounds cheap/stupid/annoying? When you do a wide open throttle or even just a good/hard acceleration it sounds amazing. I'd probably argue though that ANY muffler at wide open/hard acceleration would sound awesome in these trucks. The worst part of getting exhaust put on is I'm now more aware of EVERYTHING that is going on with the engine/transmission. V4 helicopter at certain RPM's is brutal. I could turn up the volume of my music but I didn't expect it to be so radically different than V8 mode. I'm aware of ALL the ways to disable V4 mode, I'm just describing what my experience has been. I also notice now how much the transmission is all over the place with gear shifting which never bothered me before when you couldn't hear all of the shift points. Lastly I thought I was perfectly happy with just a single out exhaust with the pipe exiting the same as the stock exit. Hearing a mean sounding exhaust only coming from one side is something I did NOT expect to bother me and I'm hoping I'll just get used to it. Worst case scenario I could probably spend another $200 with the same shop to swap out the muffler and get dual exit exhaust but it's something you might consider. Overall it has made the truck much more fun to drive. FUN to drive. The truck was already amazingly quiet, smooth (other than my fishbiting/transmission issues) but the exhaust really made it more fun to run around in. I took it on a adventurous back-roads drive over the weekend and I had a grin on my face the entire time. Obviously I'd love to get some video/sound for you folks but I promise you're better off just doing SOMETHING instead of doing hours and hours of research and not making a decision. Make a decision, get it done, move forward and redo it if you don't like how it turns out.

Feel free to ask me any questions!

https://imgur.com/NJNDSSr
https://imgur.com/93fnL0M
https://imgur.com/t1x31Rm

Edited April 16, 2019 by glendon66

kennerz · April 17, 2019

Had a similar set up (3" magnaflow 14" race muffler) on a 4.8 LS based regular cab. And yes they are kinda loud. Nice mellow magnaflow tone but under acceleration you knew you had an exhaust. Droned quite a bit, but to me is expected with a loud exhaust. Don't think I would run one on an LT based motor. Not that they sound bad at all, just like you said, these engines/trans make a lot of unexpected noises (prob why they have soo much sound deadening) but also upsets the overall quietness of the truck.

For me the 14" picked up some power and torque, flowed much better up top. Think I'll go with the standard 12909/14909 22". 14" sounds really great under throttle though and under a load when there are some rpms involved. To me magnaflow is always a good choice for performance and quality.

MeanGreen1911 · April 18, 2019

Do you think the 14" would be "calmed down" with the resonator left in? I plan on only swapping the oem muffler and I am thinking I could use a louder muffler. I want it to make a little noise but not have drone while commuting.

glendon66 · April 18, 2019

6 hours ago, MeanGreen1911 said:

Do you think the 14" would be "calmed down" with the resonator left in? I plan on only swapping the oem muffler and I am thinking I could use a louder muffler. I want it to make a little noise but not have drone while commuting.

Unfortunately I couldn't say for sure.