[5m7m2j]

Still breaking in my 7M-GTE swap. But I have spent enough time in the car to know I need to silence the exhaust. Getting 85dB with the slightest throttle at 65MPH. Drone!!!

I got the "quiet" Brullen system, 3" with high flow CAT, resonator, and 14" long muffler. Anybody tried different mufflers on their 7M turbo MKIIs?

 

[williamb82]

i run a full 3in back with a magnaflow muffler (3in in dual 2.5in out straight through). i liked the way it sounded. it was deep and throaty. it did resonate in the car but the stereo easily covered that up. although it wasnt the average stereo.
william

 

[pdupler]

On the 6mgte, I have a 2.5 inch system with a high-flo cat and a magnaflow with dual outlets. It has the most awsome sound at idle and there's relatively little droning inside the cabin at speed. I've always been particular about my exhaust sound and spent lots of money trying lots of different combinations. I do know this, tho, dropping from 2.5" down to 2.25" on an n/a car, all else staying the same, makes a big improvement in the cabin noise. I think your best bet is going down from 3" to 2.5". I know you didn't want to hear that now that you've spent money on the brullen system but I doubt any muffler you install at the end of that 3" pipe is going to get you where you want to be. I always advise people to stay conservative on the exhaust size unless its a race-only car. That droning in the cabin at speed will really wear you down if you drive the car daily.

Phil D.

 

[sloopercat]

On my old Brullen, with a basically stock 5M with no cat, it was way too loud. Had them build me another resonator to go in place of the cat. You can get any muffler shop make one out of a glasspack muffler.

Noise is a personal taste issue, I like them close to stock quiet. The 3" 7MGTE system built using a Walker truck muffler is quiet.

 

[Supra Bob]

Phil touched on an idea I used on a few Big Block Chevies I needed to quiet down (The cops told me that if my exhaust set off one more house alarm, I was gonna go to jail for attempted Breaking and Entering). Take a glasspack and stick it "up stream" of you main muffler. It should quiet things down without loosing too much power (On a 454 BBC at 11:1 compression, it dropped me from [email protected]'s to 70 db @ 3000rpm's, with only the loss of 5 HP).

 

[WadeT]

Still breaking in my 7M-GTE swap. But I have spent enough time in the car to know I need to silence the exhaust. Getting 85dB with the slightest throttle at 65MPH. Drone!!!

I got the "quiet" Brullen system, 3" with high flow CAT, resonator, and 14" long muffler. Anybody tried different mufflers on their 7M turbo MKIIs?

It's gonna be hard to have a high flow exhaust and make it quiet at the same time. The Brullen isn't even a 3" in two 2 1/2s out is it? You could get a premuffler installed or just op for ear plugs like I do. :lol:

 

[Malibyte]

I have 2.5" Brullen cat-backs on both of my MkIIs. Interestingly, the '84 with the 7M-GTE is quieter SINCE the swap...I'm running a 3" elbow and 3" high-flow cat with a custom 3" downpipe and custom flange into the 2.5" cat-back system. It's really not obnoxious at all with the 7M-GTE. Curiously, the '85 with the 5M-GE is noisier both inside and out than the '84 - despite the fact that its muffler is 10cm longer than the one in the '84. Part of the problem is that it needs a new gasket between the cat and the Brullen, and also that I had to have a piece of metal tack-welded between the cat-back piping and the frame to keep the drive line from rubbing against the exhaust - just a case of not-quite-fitting perfectly. If anyone has a better idea for doing this that won't transmit as much noise to the passenger compartment, I'd appreciate the advice.

Thanks!

 

[SupraFiend]

a gte should be quiter, all the noise has to pass through the turbo. Its already been said here but its the best answer, get a glass pack pre muffler/resonator, whatever you want to call it. Look in them all, don't get one with baffles, get one with perforations and it will not do a thing to your hp but will do wonders to your sould level and quality.

 

[5m7m2j]

Thanks for the posts so far.

The exhaust currently has a 3.5" diameter, 14" long resonator. Are some suggesting that I could replace that with a better resonator?

The thought of 2.5" in exhaust had crossed my mind, but obviously due to expense, I want to wait on that one. How would flow and noise levels compare if I introduce restriction at the muffler, rather than stepping down to 2.5" after the CAT?

I've read the "rule" that you should get a muffler that will flow at a rate >= 2.2*CrankHP. Does the same rule and formula apply to turbo charged cars?

Basically, I can get a longer/wider straight through design. Would it reduce DB enough? Or I can get a "Turbo" styles. Would that be too restrictive? (Borla does have a "Turbo" style they claim will support up to 450HP, much higher than the Dynomax Super Turbo). I am also under the impression that Flowmasters will flow even less than "Turbo" style.

And to save someone the trouble, Turbo muffler does not mean it's specially designed for a Turbo car. LOL.

 

[SupraFiend]

theres no need to add restrictions, its easy to get the db you want without resorting to baffles or convoluted passages. In example, my old 82 had a cat back with nothing but a generic straight through perforated muffler on it. It wasen't even that big, yet it sounded great and was never too loud. Now with my new exhaust on my new car I have an ultraflow twin exit straight through stainless muffler, and the thing does almost nothing. But its the design of the muffler, one of the two passages is not even perforated, and its the passage most of the gas comes out. I had to add a non baffled glass pack resonator to make it bearable. Now it sounds great but its still loud, much louder then the old catback on my 82. Basicly it comes down to the design of the muffler, that will affect noise levels more then anything else, including cat design and piping size. Either replace the muffler, replace the resonator, or add another resonator.

 

[jimvegas00]

I'm running mandrel bent 3" exhaust on my 7mgte. 3" high flow cat and an X-CELERATOR muffler. No idea on the specs on this muffler, but it has almost no drone. Still has a deep sound, probably due to the 3" exhaust. Actually, it's a little quiet for my taste. I end up driving around with the windows down and stereo off so I can listen to the exhaust. Or maybe that's just me. All in all it's quiet inside and sounds pretty good outside.
HTH
Jim

 

[5m7m2j]

The noise from my exhaust drowns out all wind and tire noise, along with most engine noise. 5db increase when pointing sound level meter towards the rear vs. the front.

Another thing is my tips end about 6" shy of the back of the car. I read that some have gotten Brullen to extend theirs. Anybody able to compare sound levels with the tips at the outer edge of the bumper vs. nestled 6" back,under the car?

 

[sloopercat]

I had the regular Bruller resonator and added the same in place of the cat in order to get quiet. The noise inside the car will definitely be less if you get the tips out where they should be.

 

[Speed Racer]

http://www.internetmediastudio.com/supra/web_pics/sup_magnaflow.jpg

I have a 2.5 in with dual 2" out Magnaflow (recently changed from a Flowmaster) and I'm very happy with how it sounds. No more droan inside the car at lower RPM ranges and it still has a nice exhaust note.

Aaron Garney and Phil Dupler both recommended it, so that's what I went with. I chose the aluminized one, because I didn't want some bling bling shiny stainless can on my car.

 

[5m7m2j]

Problem Solved: 6db+ drop with Flow Back added

Well I finally found a muffler shop that was interested in trying to solve my problem and had some good ideas. We started with a Low Back in place of the existing resonator. The shop guessed that the noise was due to air bouncing around in the pipe. The low back gently swirls the air to get it flowing smoothly without increasing back pressure.

I dropped from 85db to 79db when cruising at 65. Full throttle 5th gear went from 94db to 83db.

Low Backs are traditionally used on dirt track race cars (I do live in the South), which I'm guessing don't always run mufflers. The shop has had good results using them on both Turbo and Big Block systems.

If you're in GA, Grand Mufflers in Marietta helped me out. It was worth the 40 minute drive.

 

[SupraFiend]

http://www.internetmediastudio.com/supra/web_pics/sup_magnaflow.jpg

I have a 2.5 in with dual 2" out Magnaflow (recently changed from a Flowmaster) and I'm very happy with how it sounds. No more droan inside the car at lower RPM ranges and it still has a nice exhaust note.

Aaron Garney and Phil Dupler both recommended it, so that's what I went with. I chose the aluminized one, because I didn't want some bling bling shiny stainless can on my car.

Hey Steph, I went with a stainless muffler over an aluminized one because I didn't want to have replace my muffler every 3 to 4 years A little bling bling doesn't hurt if its done right, and functional :wink:

 

[Speed Racer]

Hey Steph, I went with a stainless muffler over an aluminized one because I didn't want to have replace my muffler every 3 to 4 years A little bling bling doesn't hurt if its done right, and functional :wink:

If Magnaflow made a stainless muffler that wasn't highly polished...I would have purchased it instead. I just don't like a shiny mufffler can on a car that has no chrome anywhere else on it. Unfortunately, the shop I went to presented me with two choices in their catalog...and that was it.

I see your point though.

 

[jdk_ii]

For a 3" exhaust, one effectively needs a 4" diameter resonator pipe.

The longer the better. This is the basis of Helmholtz theory.

Then comes the muffler.

Again, the longer the better.

Straight through provides best performance.

There is a fundemental problem with too large of an exhaust pipe.

As gases cool, they become more dense, later down the pipe.
Hence, becoming it's own obstacle. An ideally tuned pipe would
maintain a consistent heat range through the entire pipe.

That's work.

The criteria I had for my muffler was to be in between a free flow, and a
stock hipo muffler. Sporty, yet reasonably quiet.

The guy designed it based on another customer who liked the end result.

It's like a turbo muffler, except with perforated tubes, and big rounded
walls used where a turbo muffler would just have tubes.

 

[lil'devil]

Right now I have a brullen with a hedder......Its loud as hell. The turbo will quite it a little. I'm hoping that it won't be that much of a diffrernce though....I like the growl.