Quieter exhaust options

I recently purchased a 2013 GT500.
Has pullies, idi1000, and full stainless works off road exhaust.
It originally had Borla Supersnake axleback but it was way too loud under all circumstances.
I put the oem gt500 mufflers on and it helped a very minimal amount but will still wake the dead at wot.
My z06 had chevys npp exhaust which would open at full throttle but around town was very quiet. Even at wot it wasn’t nearly as loud as my Shelby is.
I want to keep the long tubes and the off road pipe but am looking for ideas.
Resonaters?
Gt mufflers?
Please keep the nonsense to yourself- I posted on the Facebook forum and had so much nonsense I just deleted the thread. Moronish comments like “hit it with your purse” to “too loud = too old”.

Thanks In advance.



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Resonators will definitely help. It’s still going to be loud at WOT no matter what with long tubes and no cats but the resonators will clean up and smooth out the tone a good bit.


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Where would I install them at? In the off road pipe ?


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Put the stock mufflers back on.

RBB said:

Put the stock mufflers back on.

Click to expand...

I posted that I put the stock ht500 mufflers back on and it’s still mega loud at wot.


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Don03cobra said:

Where would I install them at? In the off road pipe ?


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Click to expand...

Between your mid pipe and mufflers.


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Don03cobra said:

I posted that I put the stock ht500 mufflers back on and it’s still mega loud at wot.


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Click to expand...

Sorry, I missed that. Any setup with long tubes and no cats is going to be very loud at WOT. As others have suggested some resonators will help a little, but I’m thinking you’ll still find that to be too loud.

Really your only other option is to go to Kooks headers with the green cats, or go back to stock headers.

Any off road pipe is not going to be quiet with an exhaust system, for more quiet put cats back on and retune with your installed stock mufflers.

"Quiet" is a relative term with this car when modded for performance, even stock they weren't "quiet".

I used Vibrant's 18" bottle resonators just off the mid-pipe. My mid-pipe is 3", so I used 3" i.d. for the resonators, necking down to 2 3/4 right after the resonator. Before that, I couldn't stand my Borla Tourings with long tubes and no cats. Anything above 1/4 throttle was way too loud, so I ran the OEM mufflers for a good while. My car is a 2012, so I don't have the quad outlets, which may be worse. With the resonators, I was able to put the Borla's back on. I haven't tried the OEM muffler with the resonators, but I'm thinking it wouldn't be that bad. But the resonators with the Borlas was at least as quiet, if not quieter, than the OEM mufflers. Now my hearing is really bad, but I got hearing aids a few months ago about the time I got the car back on the road, so I'm thinking the resonators did a pretty effective job.

Nothing will be as quiet as the complete stock exhaust and cats if you're really noise sensitive.

If you're not hell bent on having headers, and want to face the labor of removing, go back to stock.
And if you want loud at the flip of a switch, add Doug's cutouts.

Might try a pretty tame Borla or Magnaflow, but having longtubes and off-road midpipe your options are limited.


Pick your poison.

Ear plugs.

So to clarify, you have Stainless Works headers and catless midpipe and stock mufflers?
I wasn’t sure if you have the entire SW kit with over axle pipes.
I’m well aware because I have a full exhaust, 2” headers, 3.5” collectors, 3” pipes and then welded in the stock mufflers.
The SW rear axle pipe kit has 3” resonated retro mufflers in it.
I think it sounds great. It’s supposed to be loud at WOT but not too loud under part throttle. You’re not going to get much quieter than stock, so you’re only left with adding resonators after the mid-pipe or then cats or then removing the headers.
First is determining exactly what you’ve got.
-J

HudsonFalcon said:

Ear plugs.

Click to expand...

Or that haha
-J

biminiLX said:

So to clarify, you have Stainless Works headers and catless midpipe and stock mufflers?
I wasn’t sure if you have the entire SW kit with over axle pipes.
I’m well aware because I have a full exhaust, 2” headers, 3.5” collectors, 3” pipes and then welded in the stock mufflers.
The SW rear axle pipe kit has 3” resonated retro mufflers in it.
I think it sounds great. It’s supposed to be loud at WOT but not too loud under part throttle. You’re not going to get much quieter than stock, so you’re only left with adding resonators after the mid-pipe or then cats or then removing the headers.
First is determining exactly what you’ve got.
-J

Click to expand...

I have;
Stainless works 1 7/8” headers
Off road mid pipe
OEM 2013 gt500 axle back

I’d really like a fairly quiet system until I decide to open u cutout or something.


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Add cats or resonators in the OEM piping after the mid pipe or learn to live with it vs. going back to stock on the manifolds.
Your current combo should sound great, I’d only expect a complaint about possible raspyness without cats.
Good luck
-J

Avon Calling

Seriously though, I had the same problem and put the entire stock exhaust system back on. I don't mind loud, but I do mind attracting attention from the law and being heard one mile away. After installing the stock exhaust manifolds and cats I decided it was too quite and I now have stock manifolds with a Catless H pipe. I like this combo very much , but I do miss the added torque of the long tubes.

If I were you I would follow what Catmonkey did with the two Vibrant 18" resonators and see if that works for you. Vibrant also makes an ultra quite resonator. Here is the link to their site Vibrant Performance ::. . Vibrant has a good reputation for quality stuff. This way you may find an acceptable sound level and be able to keep the long tubes.

Here are some other links you can peruse on the subject:

Ingredients to bake a non-raspy exhaust w/ headers & high flow cats

Want to get rid of the popping/trumpet exhaust

https://forums.corral.net/forums/general-mustang-tech/496793-exhaust-drone-completely-gone.html

https://www.svtperformance.com/threads/looking-to-remove-rasp-any-resonator-options.1125038/

Ditch the O/R midpipes and get a Kooks high-flow cat pipe. That, with the stock mufflers will get you a rumble that is louder than stock, but not obnoxious by any means.

I went with O/R pipes on my old GT, and my ears regretted it. I'm extremely glad I went with the Kooks HF Catted H-pipe on the GT500. It quiets down nicely when you want to be low-key. Under load, it's fantastic. I've never redlined the car, but I have done a few spirited romps to ~5000rpms and it definitely makes itself heard.

Your going to need either cats or resonators for sure if keeping the headers, the only muffler option thats a littler quieter then stock but still has that same kind of wubwubwub sound is the Ford Racing Touring (SVT spec part number not GT) not to be confused with Borla Touring which is significantly louder under throttle. Also side note.... which shape mid pipe do you have? X or H? H pipe are louder then X due to design so if you have an H, then an X would quiet it down some but introduce more rasp... also another total wild card, if you somehow modded up a mac pro chamber midpipe it will significantly quiet down an exhaust and sounds great while your at it.

high flow cats and resonators are my vote