Recently added Borla touring system to new 2024 5.3 Tahoe z71 - big mistake- gas mileage has declined- and noise level way higher than expected- had added K&N air filter some time before adding Borla - everything ran well - but adding the Borla threw everything into tailspin- Can’t say Borla has been any help - thinking of adding resonators to system but don’t know if that will be of help - anyone out there been down similar road - really like my Tahoe but Borla changed everything
Not a Borla fan
- Thread starter Oldmac
- Start date
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Joseph Garcia
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- Aug 2, 2018
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Welcome to the Forum from NH.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
Yes, changing mufflers to obtain a different sound can be a crap shoot at best. You never know what you got for sure, until it is fully installed. I believe that a resonator will reduce the sound volume, but it may also change the tone of the sound, which you may or may not like, either.
IMO, changing a muffler should not change your gas mileage, so I don't believe that they are directly related to each other. Is it possible that something got disconnected during the muffler conversion?
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
Yes, changing mufflers to obtain a different sound can be a crap shoot at best. You never know what you got for sure, until it is fully installed. I believe that a resonator will reduce the sound volume, but it may also change the tone of the sound, which you may or may not like, either.
IMO, changing a muffler should not change your gas mileage, so I don't believe that they are directly related to each other. Is it possible that something got disconnected during the muffler conversion?
mountie
Supporting Member
Confirm if your oxygen sensors were properly replaced...... Do have any warnings on your dash? A K&N filter won't change your mileage much ... A Borla exhaust will just make your truck louder, but not much of a mileage difference that you seem to think is much worse. The biggest gas mileage improvement is your foot on the gas peddle. Check for codes!!
And, WELCOME TO THIS FORUM !! ( From SE Florida )
Not sure how to check sensor - do I just pull it out and reinstall- do appreciate responses - I am an old guy -76- not in good health- Tahoe may very well be my last ride and sure want it to run well
Last edited by a moderator:
Forgot to add - no warning lights - just watched video on o2 sensor replacement- have to assume Borla provided place for number 4 downstream sensor - will crawl under it tomorrow and see if I can see #4 - don’t know what could have been done to damage it
mountie
Supporting Member
My memory is, ( on my '05 Yukon)..... The downstream O2 sensors rarely effect drive-ability that much, as you are concerned with your ride, even if it throws a code..
But could it effect gas mileage- because something sure did
Got underneath today - the o2 sensors left and right are in the catalytic converters and not in the pipe - which confuses me even more - when the shop installed the Borla system they could not have disturbed the o2 sensors - I am totally confused on the matter - installing the Borla system somehow someway was very bad for my truck - live and learn I guess
mountie
Supporting Member
All 4 of them?? ( Well, there's 4 in my '05 )
No - just the downstream two - upstream 2 are in engine bay
