6.6L L8T Gas Exhaust Options - MBRP, Borla...

[powderMonkey]

Time warp!  I finally spotted the MBRP T304 in stock at Summit Racing, and drove up and got it from their Cleveland store, and also the matte black tip.  I just installed it on the 4-post lift at the shop yesterday.  I only drove the 5 miles home last night because I was exhausted (no pun intended) but it does sound good!  Not too loud in the cab but you know it's there. I am headed back to the shop now to do a couple other things (we are closed today), and I'm going to get some pics and videos, and will reply back to this soon with some info and what I learned from the install.

[sheath]

4 hours ago, powderMonkey said:

Time warp!  I finally spotted the MBRP T304 in stock at Summit Racing, and drove up and got it from their Cleveland store, and also the matte black tip.  I just installed it on the 4-post lift at the shop yesterday.  I only drove the 5 miles home last night because I was exhausted (no pun intended) but it does sound good!  Not too loud in the cab but you know it's there. I am headed back to the shop now to do a couple other things (we are closed today), and I'm going to get some pics and videos, and will reply back to this soon with some info and what I learned from the install.

 

looking forward to this!

[sheath]

double post... Sorry!

Edited January 29, 2022 by sheath

[sweatandsteel]

For those interested, I just got an email from Magnaflow that their street series cat-back exhaust system is available again for the 6.6 gas engine. I need to go make some money....

[Builtrockhard]

On 1/24/2022 at 8:13 AM, powderMonkey said:

Time warp!  I finally spotted the MBRP T304 in stock at Summit Racing, and drove up and got it from their Cleveland store, and also the matte black tip.  I just installed it on the 4-post lift at the shop yesterday.  I only drove the 5 miles home last night because I was exhausted (no pun intended) but it does sound good!  Not too loud in the cab but you know it's there. I am headed back to the shop now to do a couple other things (we are closed today), and I'm going to get some pics and videos, and will reply back to this soon with some info and what I learned from the install.

So what’s the latest? I’m looking to get this system for my 2022 AT4 HD

[sweatandsteel]

Well after doing lots of research I discovered the Flowmaster Outlaw stainless dual exhaust system for the 6.6 gas and took the plunge. It was delivered on Friday and hope to get it installed over the next couple of weeks and will update everyone on how it goes.

[Mic_]

On 3/9/2021 at 9:57 AM, powderMonkey said:

I was wanting the MBRP T304 system, so I called MBRP yesterday and got a recorded message that they are not taking calls, and to contact them via the website.  I did that and got an instant response, but it was not at all what I wanted to hear:

 

ME: I am wanting to purchase T304 exhaust part number S5093304 for my 2021 2500HD. Are those in stock and available to ship? If not what is the lead time roughly? And would it be possible to swap out the chrome 4" ID 5" OD tip, for your black dual wall 4" ID 5" OD tip part T5053BLK? Thank you!

 

MBRP: Sorry, they are out of stock and it could be 6+ weeks at this point. Sorry, you cant swap tips.

 

Borla's own website says "coming soon" for our trucks, yet it is listed as an accessory on the official Chevy Accessory site.  What is the deal with that?  Has anyone successfully gotten a Borla direct from Chevy?  If so what was the lead time on that?

 

Official Chevy Accessories Borla Cat-Back Link

 

Any info fellas?  Or other options?  Thanks!

 

 

looks like amazon 

bought all there stock up??

 

https://www.amazon.com/MBRP-S5259304-T304-Single-Back/dp/B00XC1JSFC?th=1

 

[CT Chevy Connoisseur]

On 4/12/2022 at 7:31 AM, sweatandsteel said:

Well after doing lots of research I discovered the Flowmaster Outlaw stainless dual exhaust system for the 6.6 gas and took the plunge. It was delivered on Friday and hope to get it installed over the next couple of weeks and will update everyone on how it goes.

good luck, personally I didn't even consider anything that wasn't 304 stainless as I don't plan on ever replacing it

[Randal Scott]

AFE makes a cat-back kit made of 409 stainless steel. For around $600.00. I found a muffler from Walker  21470 with 3.5 inch inlet and outlet. Probably have to add a short piece of pipe to the tailpipe. 

[EPL]

I just installed a Borla S-Type Cat Back on my 2023 HD with  a 6.6 gas.

I received it 2 days after I ordered it from S & S Exhaust. 

All stainless with a black tip - looks great and sounds awesome!!

Really satisfied with it!

Install took less than an hour!

[Epsilon Plus]

I just came home from the exhaust shop. Had the place weld in the Magnaflow (assuming a similar one to the online kit) and a MF tip that I bought online. All in I'm at $540. Great price.

 

However.......

 

 

If definitely has a drone at 1,500-1800RPM under light acceleration. Unfortunately, where it spends most of its time in traffic. Don't know if I'm getting old or it's just my ears but I went back and got the stock muffler to take with me just in case I don't get used to it. Its fine below 1500 and above 1800, just has a drone at that unfortunate spot.

 

Exhaust guy was surprised as he says these are just above stock. It really isn't loud, more bass-y for sure which I was shooting for but the drone might drive me back to stock. I'm surprised some of you are ok with much louder and race-y-er mufflers on these. Wonder if its the extra load from the 37s I have on.

 

Overall disappointed so far.

[CT Chevy Connoisseur]

7 minutes ago, Epsilon Plus said:

I just came home from the exhaust shop. Had the place weld in the Magnaflow (assuming a similar one to the online kit) and a MF tip that I bought online. All in I'm at $540. Great price.

 

However.......

 

 

If definitely has a drone at 1,500-1800RPM under light acceleration. Unfortunately, where it spends most of its time in traffic. Don't know if I'm getting old or it's just my ears but I went back and got the stock muffler to take with me just in case I don't get used to it. Its fine below 1500 and above 1800, just has a drone at that unfortunate spot.

 

Exhaust guy was surprised as he says these are just above stock. It really isn't loud, more bass-y for sure which I was shooting for but the drone might drive me back to stock. I'm surprised some of you are ok with much louder and race-y-er mufflers on these. Wonder if its the extra load from the 37s I have on.

 

Overall disappointed so far.

Could be one of those you get what you pay for kind of deals. I've had the MBRP 304 Stainless Exhaust on mine for about 3 years, love them, not loud but you know I'm coming

[Epsilon Plus]

Dunno. It's a 22" stainless Magnaflow. Nice muffler. Not short or loud. Just droney in that 300 RPM range. 

 

I need to get it out on the freeway at 70+ and tow something with it before I decide to go back.

 

Good thing is it doesn't bother the wife at all. Maybe I'm just getting used to it since it used to be SO quiet.

Edited February 15, 2025 by Epsilon Plus

[OS RR]

6 hours ago, Epsilon Plus said:

22" stainless Magnaflow

 

 

Huh.. I've got a 22" Magnaflow knock off (from ebay, 3.5" 5x11 offset/offset). Haven't had it put on yet, guess we'll eventually see if it does the same to mine.

 

Stock tail pipe out the back still?

 

Wonder if a small resonator before the muffler would help?

 

The 18 year old in me has been eye'n the flowmaster Outlaw but, I'm afraid it'll live up to its "Drone master" nickname.

 

Got any pics of it?

Edited February 15, 2025 by OS RR

[Epsilon Plus]

I was thinking the same thing about the res.