Borla touring vs. Flowmaster 40???

shadysneed · September 24, 2020

Hello all,

I'm looking to upgrade just the muffler on my 2020 Denali 6.2L. Has anyone done this on the new generation Sierra? I want to keep the cat, flappers, resonators, and just swap out the muffler. I just want a little deep rumble, but I don't want piss of the neighbors either. I also don't want any drone. Not even sure I can do just the muffler using Borla, but I know I can using Flowmaster. Any incite would be appreciated

aragrev7 · September 24, 2020

I have some insight for a bit of a different setup.
I’ve tried both magnaflow (installed ~2 months ago) and now flowmaster (swapped yesterday) cans on the 2020 Sierra AT4 5.3L. Full dual exhaust from front to back straight off the headers.

Sounds great start up on both. But once idling, it’s too quiet. If that’s a thing. I mean I paid for a growl, and it’s there, but it sounds stock at idle. With this 10 speed, any cruising or stable speed, it’s also too quiet for what I was expecting. I’ll have to break this one in a bit. I was expecting something like Borla s-type sound out of the flowmaster, but it’s definitely under that.

My Acura was louder at start up and idle by far, and that was Apex’i Touring, nothing like the massive Greddy exhausts others were using.

I’ll see if I can get you a clip of the flowmasters.

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BluegrassMotorsport · September 25, 2020

I just had the same debate on my 6.2 and decided to muffler delete it. Man... what a difference. I left all flappers and resonators in. Cost me $75 and sounds incredible. No drone under 80mph and then a very, very slight drone afterwards. The flappers really help. It isn't too rowdy for neighbors in my opinion. Here's a cold start for you. It calms down really quickly after. I would try it out and worst case scenario, you don't like it and stick a muffler back in its place.

jbshoo · September 25, 2020

I did the gmc performance exhaust on my 19 before it got totaled, I just picked up my twenty and not sure what to do either. I may just do the Borla touring... we will see. Your truck sounded good at idle.

aragrev7 · September 25, 2020

As promised.

2020 GMC AT4 5.3L

Cold start up with full dual exhaust, headers to tips. 1 x-pipe, Flowmaster mufflers.

Cold start to idle, thought it was done spinning down, but it actually got even a little more quiet.

It’s doing well, but not quiet as aggressive as the Borla S-type cat-back. It’s in a bit of a corridor, so sound might be bouncing back a bit.

BlackRST · September 25, 2020

My brother did the flowmaster outlaw. It's definitely not too quiet haha. It's loud on start up and then mellows down to a growl that's just enough on highway and around town until you get on it. It crackles a bit on start up too which is sorta fun.

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shadysneed · September 26, 2020

On 9/24/2020 at 8:37 PM, BluegrassMotorsport said:

I just had the same debate on my 6.2 and decided to muffler delete it. Man... what a difference. I left all flappers and resonators in. Cost me $75 and sounds incredible. No drone under 80mph and then a very, very slight drone afterwards. The flappers really help. It isn't too rowdy for neighbors in my opinion. Here's a cold start for you. It calms down really quickly after. I would try it out and worst case scenario, you don't like it and stick a muffler back in its place.

Thanks. Sounds good. Definitely something to think about