JBA 40-1536 SS Catback installed!

[blackbetty14]

Picked up a catback for a good price $450 or so new and it’s all 409SS with 4.5” 394SS double wall tips. I quickly coated it with burnt bronze ceramic coating. The muffler is a single in 3” out 3” with ypipe after and dual 2.5” tailpipes no resonators. The muffler makeup is straight through but with a twist (designed to kill drone) it’s dual 2.5 or 2.75 tubes with a ypipe in and out with lots of area to cancel out waves. The muffler is pretty big at 22”x11”x6”.

Installed the catback today. Install was okay, mostly just figuring it out without instructions and getting it to line up decently. It does fit fine and changing the exhaust clamps for band clamps made it more annoying I’m sure due to bend location at slip fits.

Started it up and it’s def got less cold start bark than the borla with ZZDP resonator tone is still deep but different than a maggy or borla. Free revs sound real good honestly but don’t have any seat time to check drone. I did pick up some sound deadening to do the rear cab to help with any that I hear.

I did do DB measurements before and after the install so I had proof of any measurable sound differences. Cold start was down from 86.6 with the borla down to 72.6 with the JBA. I also have interior measurements I will compare once I get some seat time with this catback and take measurements.

Here’s a video to show the idle and free revs.
https://youtu.be/WGwGokSCE74

I hope this helps someone, I found little to nothing on lots of searches online but like that it’s a single in/out muffler so I could swap in something else easily to change it up.

 

[blackbetty14]

Was able to get some seat time on my way to work this AM. Startup bark is much less adbrupt compared to the Dual muffler borla setup. Interestingly no drone either however the tone changes at 2k like it gets alittle more aggressive from there up but cruising below 2k no drone. It’s a different tone than the deep borla sound and I like it. Maybe it’s due to not having resonators but even goosing it with medium throttle it’s not nearly as loud in the truck as before. So I assume it’s maybe a little quieter outside as well but I will have to wait for nice weather to hear with the windows down.

(Max dba's)
Cold start with borla in cab was 65.5dba
Cold start with JBA in cab was 61.9dba
Driving Borla in cab was 75dba
Driving JBA in cab was 72.8dba

Whats interesting is the frequencies in the DBA screenshots attached. the 2nd one (65.5 borla) was cold start inside the cab vs the JBA which was 61.9 but look at the graph and the huge purple spike which is a SPIKE in sound and look at how much higher that is vs the yellow/green line which is live. That's the "bark" I'm referring to which as you can see the JBA at 61.9 doesn't have that spike area. I gotta figure out the shorty header noise as you can hear it even more on acceleration now with this exhaust.