Exhaust system modifications for my '03

With all due respect to the much touted Borla system, I would like to know if anyone has bypassed the third catalytic converter and resonators? I have a muffler guy that thinks that will lower my back pressure a bit and give me the sound I want. The third converter is after the 2nd bank O2 sensor so it shouldn't affect the computer, right?

June 2020 Moderator Note: Check out this thread for 02-05 Ford Thunderbird Performace upgrades- https://forums.fordthunderbirdforum...5-ford-thunderbird-performance-upgrades.5002/
 
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Aznav

Well-Known Member
With all due respect to the much touted Borla system, I would like to know if anyone has bypassed the third catalytic converter and resonators? I have a muffler guy that thinks that will lower my back pressure a bit and give me the sound I want. The third converter is after the 2nd bank O2 sensor so it shouldn't affect the computer, right?
Virginia (for now...) allows straight pipes. Bad, bad, bad sound but you won't have an "intimate" conversation until you are cruising. Just my two cents.
 
Way back in the day my college roommate in Virginia was pulled over for loud exhaust. He spent the night at the county jail for another reason. I was lucky to have gotten out of the car earlier in the night.
 
With all due respect to the much touted Borla system, I would like to know if anyone has bypassed the third catalytic converter and resonators? I have a muffler guy that thinks that will lower my back pressure a bit and give me the sound I want. The third converter is after the 2nd bank O2 sensor so it shouldn't affect the computer, right?
I put a Borla on my 03, and sounds great, don't know if the bypass all the stuff but I pass inspection every two years
 

BirdTMan

Active Member
Unless you are going to install lake pipes / side pipes I would not go that way. It is not going to give you the sound that you think it should plus it will set off lights that will not reset. I did go with the Borla system, Found on Ebay for 830 bucks and set my car up on jacks in my garage & did the install in three hrs. You should look up some one close by that have installed on there T Bird and drive it to get the full effect. It will release back pressure and increases horse power & increases gas mileage, The sound of muscle is perfect for this Sport car. Borla is worth every penny.
 

Frankie the Fink

Well-Known Member
I agree; instead of trying to rig some "jacked up" system that a local "muffler guy" thinks will make the car sound better, like we did in the 1960's, before computers and OBDC codes -- go with a system engineered for these specific applications by professionals.

Otherwise, if all you want is more sound when you take off there is always this:



You won't Bubba-up your car and can turn it off when you want.....
 
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Come on this isn't a haul ass sports car do you really want something that is going to rumble at a stoplight and at cruising speed the resonance drives you crazy cause you cant carry on a conversation or hear the radio without talking over the noise or turning the radio up louder than the exhaust
this car is a luxury cruiser you should keep it that way
 

Aznav

Well-Known Member
I was planning on keeping the stock mufflers. I don't want it loud. Just a little more noise when I accelerate...
That's probably how this will end up for me. Putting Flowmaster's on next week. It's somewhat humorous when a kid with a rice-burner pulls up next to me and starts revving his engine. Sounds like an angry bumble bee. (-;
 

Frankie the Fink

Well-Known Member
Not a big fan of the small Japanese cars with the f*rt pipes and the park bench rear wings....but at least they are car guys (who watch too much "Fast & Furious" sequels).

I've struggled with retro bird sound a bit myself and have decided to stay stock. The current sound is not great but acceptable in a cruiser IMO...
 
That's probably how this will end up for me. Putting Flowmaster's on next week. It's somewhat humorous when a kid with a rice-burner pulls up next to me and starts revving his engine. Sounds like an angry bumble bee. (-;
I have been doing a little bit of reading on resonators and mufflers. Also I checked out some Jaguar forums. It seems as though removing the resonator is a bad idea. Now I'm leaning towards just changing out the stock Mufflers with something with a more aggressive tone and leaving the resonator. Let me know how yours works out please.
 

Aznav

Well-Known Member
I have been doing a little bit of reading on resonators and mufflers. Also I checked out some Jaguar forums. It seems as though removing the resonator is a bad idea. Now I'm leaning towards just changing out the stock Mufflers with something with a more aggressive tone and leaving the resonator. Let me know how yours works out please.
You bet.
 

cobrajeff

Active Member
I had a local muffler shop replace those huge, ugly resonators in my exhaust system with small bullet-style resonators (similar to what 1965-66 Mustangs with dual exhaust had. Also requested him to have the tips extend about 3/4" further out from the valence when he welded it back together.
I am 1000% happy with the result - it has a mild throaty sound under acceleration, and it is totally quiet at cruising speed, with no resonance.
And it only cost me 250 bucks! IMG_4017.JPG IMG_5065 C.jpg IMG_6785.JPG
 
The pipe is 2 inch. If you are doing clamp on then your new parts should have a 2 1/4 inch inlet. Most people recommend against changing the resonator (close to the catalytic converter). It controls back pressure and can negatively affect the way the car runs. Instead change the mufflers (closest to the tail pipe). Please let me know what you end up doing and how happy you are with the results.
 
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