MBRP cat back on 5.3

ShamrockShooter · January 26, 2017

After ridiculous amount of research I pullled the trigger on Flowmaster American Thunder. Lifetime warranty on everything and after 20% discount and $75 rebate ended up being $528.

man, now you got me second guessing myself. the first time i tried that code on the flowmaster it didnt work, so i thought it wasnt valid on flowmaster. for a hundred bucks more, i might just have to order the flowmaster and return the mbrp.

SavageSierra · January 26, 2017

So was it the helicopter noise in V4 under light acceleration when the truck is starting to get under load but tries to stay in v4, or just the humming sound of a loud exhaust at highway speeds that was the issue? i figured i would give it a try and if it was bad i would get a range afm to turn off v4. did you consider swapping a different muffler in place of the mbrp?

It was the v4 helicopter noise for sure at low speeds and on the highway. I considered getting a range AFM but decided to save my money for a tune when my warranty is over. The drone isn't THAT bad but it started to annoy me as I do frequent long distance highway trips. The exhaust in v8 mode is a dream on the highway and in town, no drone at all just a nice normal v8 sound.

All in all it should be fine and I think you will be happy with it. If not just throw a range on there and call it a day.

ShamrockShooter · January 26, 2017

It was the v4 helicopter noise for sure at low speeds and on the highway. I considered getting a range AFM but decided to save my money for a tune when my warranty is over. The drone isn't THAT bad but it started to annoy me as I do frequent long distance highway trips. The exhaust in v8 mode is a dream on the highway and in town, no drone at all just a nice normal v8 sound.

All in all it should be fine and I think you will be happy with it. If not just throw a range on there and call it a day.

That is good to hear. As long as the v8 cruising noise is good, i can live with getting a range to turn off afm. i bet it was quite a difference when you put the factory back on. i remember taking the flowmaster off my 2005 before selling it. you really dont realize how quiet the stock exhaust is.

snowman44 · January 26, 2017

Everyone has different experiences with different brands. On my first silverado I had a flowmaster and loved the sound but it rotted with upstate winters and had to replace. Than on past GMC and Silverado I had MBRP because of price and they rotted just as bad if not worse and I didnt like sound as much but price was right. FYI I keep my trucks for at least 5 years so it wasnt like they rusted after just one year. With a lifetime warranty on everything that comes in the flowmaster box for that price it was a no brainer to me and half the price of BORLA and CORSA.

ShamrockShooter · January 26, 2017

I usually keep my trucks about 5 years so when the mbrp rots out it will help about time to put the stock exhaust back on and trade it in on an F150

Sierra 5.3 · January 26, 2017

I'm leaning more towards the Volant over the MBRP. Let me know what you think of the MBRP. Post sound clips if you can.

ShamrockShooter · January 27, 2017

First thing i want to do is measure up the mbrp muffler to see if any other flowmaster or magnaflow mufflers would be a direct swap. I kind of had my heart set on a flowmaster 10, and talked myself into the mbrp on price. although that could all change when i fire up the mbrp if the sound is as good as others have said. Fedex is saying maybe i will get it friday, so it might be on the truck saturday, even if its still snowing. The colder your hands, the faster you work.

ShamrockShooter · January 27, 2017

I also find it amusing that everywhere i look on this forum, i now see AutoAnything adds showing MBRP exhaust systems. Man Google sure does know every flipping thing I do on the computer. To bad they aren't smart enough to know I already made the purchase, so they can stop showing me the ads.

Sierra 5.3 · January 27, 2017

I also find it amusing that everywhere i look on this forum, i now see AutoAnything adds showing MBRP exhaust systems. Man Google sure does know every flipping thing I do on the computer. To bad they aren't smart enough to know I already made the purchase, so they can stop showing me the ads.

Google security is great, privacy...not so much. You can change the configurations in the browser to help with them not tracking you. #NerdAlert

ShamrockShooter · January 28, 2017

So I'm glad it was 28 degrees outside, because i was sweating like a dog getting the factory exhaust out in one piece. the MBRP went on in 15 minutes after that. 2 hours total install and clean up with my neighbor helping for a few to get the old exhaust out.

Cold startup sounds like a late 60's muscle car. driving around the block cold was almost nauseatingly loud. up on the highway was not too bad cruising, but there is no way you should consider the mbrp without turning off AFM. it does indeed sound like an old subaru boxer engine with a bad muffler in V4.

I never thought I would say this, but this mbrp kit is just too damn loud for this being a "family" truck. Even my gear head neighbor who use to race sprint cars said it sounded awesome on startup, but was way to loud for the "neighborhood" when i go to work at 6 am.

the mbrp is 26 inch overall and the case is 22 inches. the kit came with a 10 inch extension pipe, so i should be able to get any 3" center in/3" center out muffler 26 inch overall or smaller and just clamp it in place of the mbrp, and make up the slack with the extension pipe they sent for the long bed trucks. as long as it isnt too wide (driveshaft)

so what does everyone suggest for an alternate muffler to try swapping in that is quite a bit quieter?

emeryz28 · January 28, 2017

well there is my decision, I will not be getting the MBRP, thank you for the write up and the good explanation on how loud it is

ShamrockShooter · January 28, 2017

after driving around all afternoon, it is amazing how fast yours ears get adjusted to the loudness. I was getting around 17.5 mpg lately. after 30 miles mix of higway, and stop and go it was over 19 mpg. that included flooring it a few times. see if that mpg holds up. think i might have to swap the muffler for something quieter.

if you live in a warm climate with the windows open all the time, it might not be that bad for you. overall, the quality of the MBRP kit is top notch, so hats off to them. just too loud for my taste.

ShamrockShooter · January 28, 2017

MBRP does have universal muffler that appears to be the same one that came with my kit. the have a loud version and a mild version. I will give them a call on monday. if my kit came with the loud one, perhaps it would be a direct swap for the mild version.

sstrev · January 30, 2017

I have this system on my 2015 5.3 Sierra as well. It is definitely louder than I was expecting, but you do get used too it. The V4 mode sucks but I think you are going to get that with any system that doesn't have the flapper. I recently started driving around in M5 mode in town to see the difference and man it is just way better, not only sounds better but feels and runs better. I am going to get a tuner to disable it myself.