Completely agree there's lots of very talented exhaust shops and welders out there. But the whole point was to not be going from stock 3.5 inch down to 3 inch. That is quite backwards from the 'upgrade' to cat back system. Also for what it's worth, last day or two since getting it on mpg has gone done substantially. Down from 15 - 16 in town to 12ish. Now I know most will say this is normal because your using your on the gas more and have different driving style to hear it, but I have been very careful to make sure my 'before' and 'after' driving style is the same as much as possible. Same routes, same idle time, RPM's at take off, coasting to stop signs, etc... Maybe it needs more time to break in and the computer to learn? Again making me wonder if the 3 inch isn't' really to small and should have been 3.5. It's really messing my mind now.. It's messing with my mind now just not knowing and now seeing the MPG drop but maybe I should just forget about it, drive it and enjoy the nice sound.
maybe a little pricy but ever thought of the GM Performance exhaust? I just got mine on my 2017 6.2 and sounds really good, nice deep tone but not overly loud. It's Borla touring but made for GM and sold as GM accessory. Sounds a lot like what you are describing as wanting. No helicopter since it has the flapper built in (at least on my 2017, not sure about the T1's)
The TSB states diagnosis beyond customer compliant is not required, so there shouldn't be any reason they wouldn't perform the flush. Heck for anyone who isn't experiencing any symptoms of this I'd still take it in and ask they do the flush. Back in 2019 dealers were informed to flush any still on the lot, so if they are doing that I can't see why anyone who brought one in would get turned away, as long as it's under warranty still and the specific TSB is referenced. Mine started the 'rumble strip' vibrating feel and took it in. Never noticed it since, this also seemed to help the harsh 2 - 1 downshifts.
No that's what I'm looking for is something that says if it's supposed to be 3 or 3 1/2. I've searched all over and can't find anything, dealer parts dept. didn't know either. When I go to Boral's site directly and search for their catback systems (non GM) it does say 3.5 inch. It does split after the muffler so maybe that's the reason I believe it's 2.5 dual out. The dealer did get it to bolt up and I specifically asked them to verify the size is right first, so right size or not it's on now. The OE clamp was reused, not sure what size it was but didn't have to get a new one. Not sure about the flange size but the OD of the pipe after the flange all the way up to muffler is 3 inch. The stock piece that came off was 3.5 inch which I still don't get how making it 15% smaller would be of any benefit. One would think the Catback would be same size if not larger for increase flow, but maybe because it's mandrel bent and has duel outlets on the muffler it doesn't need to be as big?
Thought I'd share an update. Fast forward 7 months and finally did get my money back for the first exhaust. (Long story there..) Then re-ordered but this time directly through local GMC dealer. When it arrived low and behold it was the exact same as the first one. This time I was having the dealer do the installation incase there were any fitment issues and I asked them to double check the fitment and they were able to bolt it up fine. So what I really don't understand is how can stock pipe be 3.5 and this only be 3 inch (pictures above) and have any better performance or exhaust flow? The flange up near the cat also is smaller and doesn't fit quite the same, and the front hanger is tilted more sideways now but it is on. This makes me think it's really made for the 5.3... BUT I now also have two different systems ordered at different times from different places that were both identical. Which is giving me mixed signals on weather it's actually right or not? I can't find any specifics on what pipe size it's supposed to be but when I look on Borla's site directly their systems for the 6.2 clearly say 3.5 inch. Anyone know the specs on what the pipe size should be for PN# 19303345 from the cat up to the muffler? End result is it's on, dealer installed, looks amazing and sounds equally as good, so as long as it's not increasing backpressure or decreasing performance should be fine, but is really bugging me not knowing weather it's right or not.
The Borla GM Performance Exhaust does. It's make by Borla to GM spec. which includes the flapper. Had one on my prior truck as well. I'll try to snap a few pictures, but it's before the muffler where the stock flapper is behind the muffler. But this is for pre 2019 models, so that could have changed with 2019/2020.
Since it alternates between drone and exhaust sound, I wonder if the drone is when it's in V4? The Borla GMPE has a flapper to help with the helicopter noise when in V4 but wonder if it effects the drone too? Interestingly enough I just got a call from the dealer that my exhaust is finally here! Going to pick it up and put it on this weekend. Mines a 2017 but shouldn't be much different sound wise from the 2019/2020's. Will report back with thoughts. Separately... This will be my second purchase of the performance exhaust. First go round I ordered off one of the big on-line parts company's and they send me the wrong one. (I ordered the right part# but what they sent me doesn't fit) But in my haste to get it put on I threw away the box before I realized it didn't fit, and now they will do absolutely for me about getting an exchange or refund so I'm out $1,000, and now another $1,000 on this new one. Expensive lesson. I can't say 100% what it fits but appears to be for the 5.3 due to the 3 inch pipe and possibly for a 2019/2020 crew cab short bed. The hangers didn't line up right and was about 2 inches short to connect up at the front connection. But regardless I'd think the muffler could be used in most any application with a little welding. So it's sitting in my garage as an expensive paperweight. If anyone is interested I will let it go for any reasonable offer. I'm in Chicago area for local pick up or will be willing to deliver with in reasonable driving distance... Brand new and unused, but no box. I just can't definitively say what make/model it goes to other than it is for the 5.3. Accepting any offers at this point
Anyone with the 6.2 done the Active Noise Cancellation calibration? I've read there is a calibration for the GM Performance Exhaust since the 6.2 has ANC and curious if anyone has done this and if the dealer would be familiar with it? Mine is still on backorder so once it comes in I'm going to ask the dealer about ANC calibration. I assume this would help with any drone?
Not to hijack the thread and I know this is a 2019/2020 forum but I just got the GM Performance catback exhaust on my 2017 with 6.2 and looks and sounds really nice. Highly recommend it. Not obnoxiously loud but not stock sounding either. For what it's worth it has just one flapper before the muffler. But I have AFM turned off so doesn't really matter to me.
I'm digging the color matched wheels and exhaust tips. Are those BGF K04's on there?
I have both GM floor mats and Line X ultra. Can't say enough positives about both. Floor mats are awesome and super easy to take out and wash and they cover all carpeted surfaces. Line X is right up there with the best money I ever spent as well. The ultra or premium I think they call it now is only $100 more and gives you fade protection. Going on three years now and still looks brand new and has gotten plenty of use.
This is a known issue. Search around and you will find many forum posts on it. You can also put a piece of rubber between the leaf's. My was clunking horribly and soon as I put rubber in between the leaf's was instantly better. I used a bicycle tire innertube and just cut sections. Much better than grease in my opinion since grease is messy and will eventually need more.
I just went up to 275/60/20 KO2 on my 2017 with the stamped steel UCA's and can say for a fact there's no rub. Using stock 20 inch wheels. It's mighty close but no rub even at full lock reverse. I also added a 1.5 level which in my opinion gives it the perfect stance with the larger tires. Not completely level but way better than it was. It now sits about 3/4 of an inch higher in the back. Even clears the front mud guards. I'm guessing a 275/65 would have some rub and maybe require an aftermarket UCA, which if you have stamped steel may not be a bad idea anyway. I didn't on mine but know it's just a matter of time.
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