I want to make my car a little quieter...

[MrAwesome987]

My car currently has a set of Ford Racing/Borla mufflers with long tube headers, no cats or anything else. I've enjoyed it for the last few years, but I'd like to make it a little quieter.

Would mid mounted resonators/mufflers make it significantly quieter? Will they even fit? The car is lowered about 1.25".

What's the recommendation?

 

[Midlife Crises]

Hi flow cats might help a bit if they dint hurt you performance. I tried mid mounted glass packs once and they sounded just awful.

 

[JC SSP]

You can try interior and trunk insulation too. Several threads on the topic.

 

[cavero]

I had the same problem when I went long tubes and high flow cats w/ the stock GT mufflers. I ended up putting in high flow cats (Kooks Green cats), resonators (Vibrant brand, but can't tell you the exact model), and Borla touring mufflers. Much quieter setup, especially at highway speed, but the bass at idle is pretty horrendous to my ears. I don't know if its the combo of the touring mufflers w/ the resonators. I bet there's a good combo out there though

 

[05Coupe]

I would go with a mid length header, high flow cat, and a pair of Flowmaster super44 mufflers. It will keep the deep growl while being nicer to the neighbors.

 

[ghunt81]

OEM mufflers with long tubes sound great and have significantly less resonance than any aftermarket muffler. I'm currently running that setup except I have cats. Still relatively loud too but it's now quiet enough I can let the car warm up in the morning without waking all the neighbors.

 

[VGMStudios]

OEM mufflers with long tubes sound great and have significantly less resonance than any aftermarket muffler. I'm currently running that setup except I have cats. Still relatively loud too but it's now quiet enough I can let the car warm up in the morning without waking all the neighbors.

Would you happen to have a video of the car staring up, idling and whatnot?

 

[ghunt81]

I need to make one but currently I do not. Will try to do it when the weather gets a little warmer.

 

[cavero]

OEM mufflers with long tubes sound great and have significantly less resonance than any aftermarket muffler. I'm currently running that setup except I have cats. Still relatively loud too but it's now quiet enough I can let the car warm up in the morning without waking all the neighbors.

OEM cats? Are the CMS camps NSR? I had a pretty similar setup (aftermarket cams, basically the same CAI, long tubes, JBA catted H-pipe (not emissions legal as it turns out), and stock GT mufflers). Definietly no resonance, but when I'd get on it, it'd get LOUD and harsh, reminded me of something outta NASCAR.

VGM, I have a video of my car on the dyno w/ the LT's and stock mufflers, but it's ~2015 phone quality.

 

[cavero]

Here's my setup now (sorta...engine's getting new cams (comp cams 127450) and going back to the stock intake manifold w/ the engine rebuild)
CAI, Ford Racing Intake, Comp Cams 127400, JBA LT's, Kooks Green Cats, Vibrant Resonators, Borla Touring mufflers

 

[VGMStudios]

@cavero thanks so much for the video. That actually sounds really good! I need to look into what is needed for long tubes cause I like the stock gt Mufflers sound.

 

[VGMStudios]

I need to make one but currently I do not. Will try to do it when the weather gets a little warmer.

Thanks so much. Looking forward to the video. No rush of course!

 

[Dino Dino Bambino]

CAI, Ford Racing Intake, Comp Cams 127400, JBA LT's, Kooks Green Cats, Vibrant Resonators, Borla Touring mufflers

Do you have the dyno numbers and sheet for that set up? Did you have underdrive pulleys, an aluminium driveshaft, or lighter weight flywheel at the time?

 

[SilverMustangGT]

I have the stock exhaust with Borla Touring mufflers. I think it has a nice sound without being too loud. I also have the DOB supercharger installed. I like hearing the surcharger whine without the exhaust drowning out everything.

 

[cavero]

Do you have the dyno numbers and sheet for that set up? Did you have underdrive pulleys, an aluminium driveshaft, or lighter weight flywheel at the time?

I went back looking for a thread when I got it dyno'd...can't find it anywhere.

Anyway, had to double check, the dyno was before I got my T56 Magnum, so driveline would've been:

- Steeda underdrive pulley
- Stock flywheel
- McCleod Street Pro clutch
- Stock TR3650
- Steeda tapered aluminum driveshaft (think it's actually a DSS sold by Steeda)
- 3.73's
- Stock 17" wheels & stock sized tires

and engine was (forgot one or two things before so putting it all together):
- Granatelli 93mm CAI (basically same as C&L racer)
- Ford Racing GT500 throttle body
- Comp Cams 127400 w/ behive springs & Livernoise limiters
- Ford Racing Intake plenum
- JBA Longtube headers
- JBA high flow cats
- stock mufflers

When I did the Kooks green cats, resonators, and Borla mufflers, all we did to the tune was restore the part of it that does emissions back to stock. (needed it to pass VA emissions inspection)

 

[ghunt81]

OEM cats? Are the CMS camps NSR? I had a pretty similar setup (aftermarket cams, basically the same CAI, long tubes, JBA catted H-pipe (not emissions legal as it turns out), and stock GT mufflers). Definietly no resonance, but when I'd get on it, it'd get LOUD and harsh, reminded me of something outta NASCAR.

No they are JBA cats on their shorty H pipe. Yeah they are NSR, not super choppy once warmed up.

I agree, on cold start it has an old school muscle car sound. On throttle they are still pretty damn loud. I keep thinking about putting aftermarket mufflers on again and then I drive it, and realize it has almost no resonance and still sounds amazing and realize there's no reason to, I just wish the tips looked nicer.

 

[Dino Dino Bambino]

I went back looking for a thread when I got it dyno'd...can't find it anywhere.

Anyway, had to double check, the dyno was before I got my T56 Magnum, so driveline would've been:

- Steeda underdrive pulley
- Stock flywheel
- McCleod Street Pro clutch
- Stock TR3650
- Steeda tapered aluminum driveshaft (think it's actually a DSS sold by Steeda)
- 3.73's
- Stock 17" wheels & stock sized tires

and engine was (forgot one or two things before so putting it all together):
- Granatelli 93mm CAI (basically same as C&L racer)
- Ford Racing GT500 throttle body
- Comp Cams 127400 w/ behive springs & Livernoise limiters
- Ford Racing Intake plenum
- JBA Longtube headers
- JBA high flow cats
- stock mufflers

When I did the Kooks green cats, resonators, and Borla mufflers, all we did to the tune was restore the part of it that does emissions back to stock. (needed it to pass VA emissions inspection)

View attachment 95124

Interesting. Your dyno curves look almost identical to what I'd expect with the bigger 127500 cams and the stock intake manifold with delete plates. The Ford Racing intake manifold typically sacrifices torque in the 3300-5100rpm range and adds it higher up, and your HP curve hadn't even peaked at 6400rpm so you almost certainly have over 350rwhp. Call it 400hp crank. With the upgraded valve springs and phaser limiters that you have, the engine could have easily revved out to 6800 or even 7000rpm.
It would have been interesting to see the results using the 127400 cams with the stock intake manifold/delete plates. I see that your planning to swap in 127450 cams to go boosted later on.

 

[cavero]

No they are JBA cats on their shorty H pipe. Yeah they are NSR, not super choppy once warmed up.

I agree, on cold start it has an old school muscle car sound. On throttle they are still pretty damn loud. I keep thinking about putting aftermarket mufflers on again and then I drive it, and realize it has almost no resonance and still sounds amazing and realize there's no reason to, I just wish the tips looked nicer.

I know polished tips were a dealer option, wonder if you could source some

 

[cavero]

Interesting. Your dyno curves look almost identical to what I'd expect with the bigger 127500 cams and the stock intake manifold with delete plates. The Ford Racing intake manifold typically sacrifices torque in the 3300-5100rpm range and adds it higher up, and your HP curve hadn't even peaked at 6400rpm so you almost certainly have over 350rwhp. Call it 400hp crank. With the upgraded valve springs and phaser limiters that you have, the engine could have easily revved out to 6800 or even 7000rpm.
It would have been interesting to see the results using the 127400 cams with the stock intake manifold/delete plates. I see that your planning to swap in 127450 cams to go boosted later on.

Yeah the interesting thing is the 127400's are supposed to give you more midrange, but the FRPP intake shifts everything to higher RPMs, so it becomes a pretty linear power curve. I overlaid it with my first dyno run (just the CAI and tune), and in the low/mid there were almost no gains, it was all high RPM. (green/purple is the CAI run)



They did end up raising the rev limiter to ~ 7200 RPM, and I did make occasional trips up there...until the run where my followers crapped out (hence the engine rebuild).

My shop and I think the 127450's are going to be pretty similar to the 127400's, but they'll have a little more lope and maybe and some slightly higher gains w/ the added lift and duration. Also going back to the stock intake though since I'm looking at a centri blower and I want to keep as much low end as I can.

 

[Jbone]

I would t use cat or resonators restricts your flow just buy quieter mufflers. Resonators