I have a little bit of a story here, so grab a drink and take a seat.

Vehicle: 23 SCrew FX4 5.0 with 3.31

Back in January, I decided to do exhaust on my new truck. I waited until well after the break in period (around 2k miles) to pull the trigger. I knew a borla cat-back would be the best way forward, but my arrogance got the best of me. “I can find a good exhaust shop to do just as good!”, said the ignorant new 5.0 owner. I had a shop install a y-pipe, removing the stock muffler, but keeping the stock resonator. “Throw it away, it’s trash now!”, he continued.

The custom set up droned so bad and caused so much pressure in my ears, I had to change it.

Fast forward to this past weekend when I installed my new borla S-Type cat-back exhaust. The first day was awesome and everything was fixed. The top end sounded amazing - crisp, aggressive sound and very quiet on the low end.

Then, after a day or two, the pressure on my ears feeling returned. When in eco mode or lower than ~1800-1100 RPMs, there’s a strong resonance pressure inside the cab. It feels similar to when you open one window on the Highway - that “wop wop wop wop wop” feeling. It’s not loud, it simply makes it feel like you want to pop your ears. After 30 minutes, it gives you a headache. I’ve had multiple people ride/drive the truck to confirm it’s not just me.

I called borla to troubleshoot. They assured me that’s not supposed to happen with their products. I have an oil change this Saturday and the Borla rep wants me to have the techs look over the installation, just to be sure.

I know the Touring is also an option; however, I’m not convinced that would remove the issue. This isn’t a “loudness” issue, but a ‘pressure’ issue. I also don’t have the original exhaust anymore (because I’m an idiot). If I could go back, I would’ve never messed with it to begin with.

So, what do you all think? What are some questions I can ask back to Borla? Should I give up and try to find a used stock exhaust?

Where should I go from here?

 

Have you looked underneath just to check for any leaks or blatant issues?

 

yes. I checked for leaks and didn’t find anything. I did notice the tips aren’t perfectly aligned, but I can’t imagine that’s it.

 

Hmm yeah would likely have been something obvious. Wondering if it is possible that some of the packing blew out. I'd be surprised given Borla's reputation though. It's weird too that even for the ATAK system, Borla claims no drone. Looking at the three systems side by side though, the S-Type doesnt look to add much on top of the ATAK. The Touring though is pretty substantial and would do a lot to reduce resonance frequencies. Wonder if you could get someone to swap you out as it looks like would be just the middle section.

Just for reference, since I love seeing side by sides:
ATAK


S-Type


Touring

 

Switching to the Touring section is my plan B. I’ve heard of Borla replacing or selling that over axle
piece for people who thought it was too loud, so I think that option is on the table.

it’s weird that a specific range of drone would be the result of the packing blowing out. I’m worried this is a symptom of something wrong with my truck. Maybe something with the cylinder deactivation?

Also, thanks for the side by side!

 

Yes, I think what your hearing in cylinder deactivation. I’m currently running 3” out with a vibrant resonator only. I know exactly the sound you’re talking about. At least I think so! Personally the first drive with the exhaust was slightly annoying but I honestly kind of like it now! I the lower rpm range and when it shifts to 10th gear the pitch changes (trombone like?) I think that is what you’re hearing. I would say drive in sport mode for a couple days to see if that resolves your issue. If so it’s just cylinder deactivation, nothing more.
If not post some sound clips. Maybe we can figure it out!

Also, I still have the factory mid section (resonator and muffler) if your close to the Houston area!

 

I didn’t even think of cylinder deactivation. Not sure why the first couple days were fine but yeah see if sport mode (if that keeps all 8 firing) eliminates the issue.

 

I agree with the others that cylinder deactivation is the most likely cause of this issue.

 

wouldn't Borla have planned for that though? I would think a big company such as them plans for a common use case like cylinder deactivation.

 

Not sure if things have changed over the years, but back in 2015, aftermarket exhaust manufacturers did not account for it. The stock exhaust on my truck had a metal flapper valve that made it unnoticeable. However, the only way to get rid of the sound with an aftermarket exhaust was to disable AFM or keep the truck in tow/haul mode and not let it use 6th gear.