Exhast drone help

Jtm35a2

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I just bought my first S197! An 06 GT 5 speed with 59k miles. My wife is complaining about the 5th gear 45 mph drone. I have to admit that it's pretty overwhelming. The car has the following mods that I can see.
Long tube headers
X pipe
Ford racing intake manifold
Cold air intake
Under drive pulleys
No cats
SLP ? mufflers
I would like to make the car more enjoyable for her ( plus it's a little raspy sounding), but also don't want to choke the sound down completely. Any suggestions on changes to accomplish my goal? Thanks in advance.
Also…..why does the site put all my pictures in upside down? Heck, I even tried putting them upside down in my phone, and the site left them upside down

IMG_4636.jpeg
 

pass1over

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cats will definitely help with reducing the sound/drone/rasp. If that's not enough, you can have resonators installed between the X and the mufflers, stagger them. OR, you can go to a bigger muffler, those tiny cans do little to quiet these cars.
 

DieHarder

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If you want to quiet it down go back to stock mufflers. If that doesn't do it replace the X-pipe with a stock H-pipe.
 

JC SSP

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If your state has emissions testing, then a good set of quality catalytic converters. If not, then stock or larger aftermarket mufflers. Those SLP are the size of a coffee can, not much for sound suppression.

Post more pics and welcome to the forum.
 

Jtm35a2

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I suggest you install a pair of high flow cats in front of the X pipe. This will reduce the drone and the raspiness while making the car emissions legal again once your tuner reactivates the rear O2 sensors.
I don’t have a tuner, which leads me to my next question. Would a new tuner just overwrite whatever is in there now? Or is it locked to whatever tune the previous owner had installed?
 

86GT351

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I don’t have a tuner, which leads me to my next question. Would a new tuner just overwrite whatever is in there now? Or is it locked to whatever tune the previous owner had installed?
That depends on what brand tune you have and if the tuner encrypted it. I just recently had a car here at the dealer that the customer paid us to flashback to stock because nobody could get into it.
 

Dino Dino Bambino

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If you don't have a handheld tuner at all, you won't have the ability to upload a revised tune to your ECU. Therefore I suggest you just replace the SLP mufflers with either a pair of good used OEM units or Borla Touring mufflers. You'll have no trouble selling your SLP mufflers 'cause there's always someone who wants a louder exhaust.
 

Jtm35a2

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If you don't have a handheld tuner at all, you won't have the ability to upload a revised tune to your ECU. Therefore I suggest you just replace the SLP mufflers with either a pair of good used OEM units or Borla Touring mufflers. You'll have no trouble selling your SLP mufflers 'cause there's always someone who wants a louder exhaust.
Thank you for the help. I bought this from a local dealer and they had it nc inspected by their mechanic of choice. Documentation for both. They have made a mistake. It’s illegal for a nc inspection station to pass a car with removed cats, and illegal for a dealer to sell said car. I think i will pursue this with them. Maybe just have them add some performance flow through cats for legal purposes. Is there even a possibility that this will cure the droning and raspy sound? Or should I be muffler hunting too? Car runs amazing as is, will one or both of those changes screw up the tune? I am assuming someone has put a tune on it, no check engine light. Although it has 4 02 sensors, just no cats between them lol.IMG_4637.jpeg
 

Samos3

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5th gear at 45mph? That sounds entirely too slow.

Stainless mufflers tend to be made of thinner gauge material which increases the tinny sound. This may not be applicable to newer exhaust systems, but the old ones (like on my 70 Mustang) tended to create a drone around 3k rpm. Something to do with the acoustic waves and type/size of the mufflers and if you have resonator.
 

MasterofDisaster

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I installed a catted x-pipe about a month ago. Still have stock mufflers in stock location. No drone.
 

Dino Dino Bambino

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5th gear at 45mph? That sounds entirely too slow.

Stainless mufflers tend to be made of thinner gauge material which increases the tinny sound. This may not be applicable to newer exhaust systems, but the old ones (like on my 70 Mustang) tended to create a drone around 3k rpm. Something to do with the acoustic waves and type/size of the mufflers and if you have resonator.
The Drone Zone on 3V Mustangs with a non standard exhaust is typically around 1500-2500rpm. This is the worst place since it coincides with typical highway cruising speeds in 5th gear.
 

Samos3

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The Drone Zone on 3V Mustangs with a non standard exhaust is typically around 1500-2500rpm. This is the worst place since it coincides with typical highway cruising speeds in 5th gear.
Interesting. Except for 1st gear, I am always above 2k. I especially don't like dropping below that in 5th. 45mph in 5th seems like it would be on the verge of lugging. Not good for bearings.
 

MrBhp

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I installed hi flow cats on mine connected to the factory x-pipe. Had the roush xtreme exhaust which is just mid pipe resonators. It was loud with little done. When I went catless it was unbrearable. I still have the pipes that I welded the the hi flow cats in. I should sell them.
 

Dino Dino Bambino

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Interesting. Except for 1st gear, I am always above 2k. I especially don't like dropping below that in 5th. 45mph in 5th seems like it would be on the verge of lugging. Not good for bearings.

It depends on your axle gearing. I have the stock 3.55 and my 255/45R18 tires are rated at 770revs/mile. At 1500-2500rpm in 5th I'm doing 48-84mph. With stock mufflers there's no drone.
 

kazman59

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Thank you for the help. I bought this from a local dealer and they had it nc inspected by their mechanic of choice. Documentation for both. They have made a mistake. It’s illegal for a nc inspection station to pass a car with removed cats, and illegal for a dealer to sell said car. I think i will pursue this with them. Maybe just have them add some performance flow through cats for legal purposes. Is there even a possibility that this will cure the droning and raspy sound? Or should I be muffler hunting too? Car runs amazing as is, will one or both of those changes screw up the tune? I am assuming someone has put a tune on it, no check engine light. Although it has 4 02 sensors, just no cats between them lol.View attachment 96727
One change at a time...
 

Samos3

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It depends on your axle gearing. I have the stock 3.55 and my 255/45R18 tires are rated at 770revs/mile. At 1500-2500rpm in 5th I'm doing 48-84mph. With stock mufflers there's no drone.
I have the 3.31 and 255/45/18. No drone, but like you, stock exhaust. The factory has the benefit of lots of engineers. With all the different aftermarket exhaust parts, it's a crapshoot on the end result.
 

Samos3

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Went for a drive today. Turns out 2000rpm is about 45mph in 5th with 3.31 gears. I really thought mph was higher at that rpm. But, 1500 rpm would be luggy and need a downshift to get decent acceleration. I know this from past accidental experience.
 

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