Well I finally got an exhaust for my 04 Denali xl 6.0! Gibson 615534 from summit racing. 409 stainless cat back dual in with a single side exit. It was tough to get all the clearances right with the axle and coil spring but we got it to work. Cold starts are awesome! Great idle tone, great burble. Acceleration is louder than stock with a very nice tone, a little aggressive. Not loud enough to piss off the neighbors. There is a little resonance (not quite a drone) at around 2000 rpm 65-73 mph that even my wife finds tolerable. With the K&n intake and this exhaust this truck is much more fun to drive. I’ll report back if I notice any mpg increase. Cheers!
Excellent, and thank you for sharing! I really like my Gibson Extreme cat back dual exhaust system, though it is significantly louder than yours. Now that you've upgraded the intake and exhaust systems, you might want to consider getting a Black Bear Performance tune, and extract the most available performance improvement from these upgrades, in order to make it even more fun to drive.
Any chance you can take a video of sound? Gonna be doing exhaust soon on my 2006 xl Denali and I’m deciding which route I want to go. I looked at some Gibson exhausts and they seem like a good deal.
Adventurenali92, I suspect that you were asking Angelo for a video of the sound for his Gibson 615534 exhaust system. In case you are interested in hearing the Gibson Extreme 65403 catback dual exhaust system, I have provided the link below: https://drive.google.com/file/d/1l0MRwwhN6KHg9jGOBfqcOfNf__SiEyqX/view?usp=sharing As can be seen in the video, the recorder was placed about 15 feet behind the truck, and not right next to one of the exhaust outlet pipes.
Thanks for the link. But unfortunately that’s a gmt900 with a different engine so it’s not going to give me a good idea of sound because I have an older truck with a different motor. I have what the OP has.
I have had a Gibson exhaust system for a couple years now and love it. But a month ago I drilled out heads and put bbk 1 3/4 primarily shortly headers. Wow should have done that a long time ago! So smoother,picked up 2 mpg and I swear it is quieter.
I've used Gibson on four vehicles; 97 Tahoe, 04 Astro, 03 & 04 Tahoe, liked them all. Nice masculine sound, minimal drone, won't wake the neighbors under normal load, but sounds like it means business under power. Deep burble at idle. Sounds like a V8 should. Nice contrast to the three golf car..... uh Prius' in the neighborhood.