muffler advice

[johnbell]

I am running a single turbo muffler on a 2 1/2 pipe, droning is awful...I am thinking of going to an x pipe and another turbo..will this stop the drone or do I need to go to maybe walker quiet flows? I have spent a lot of bucks to make this car quiet and that is what I really want. I have a mild to middlin 350, headers, slightly lumpy hydralic cam, roller rockers, air conditioning, all working everything. But so far the car is uncomfortable due to exhaust noise..experience is appreciated!! Especially if you have part numbers that work!! I forgot to add that I cut 5 1/2 inches out of the spare tire bucket and put a Sentra donut in to have room for another muff..

Edited January 13, 2012 by johnbell

[surpip]

Might whant to look into some resonator http://www.velocityshop.com/product/vibrant-exhaust-resonator-2-5-inch-12-inch-long_548.html

I think a resonator would be your best bet because finding a muffler that can do all that would be lardge and hard to fit.

As for me, loud an proud kus loud pipes save lives!

 

Thanks RBZ..dam you auto correct.

Edited January 14, 2012 by surpip

[DREW RBZ]

Here is a link to a neat site that gives some explanation.

 

http://auto.howstuffworks.com/muffler4.html

Edited January 14, 2012 by DREW RBZ

[RebekahsZ]

Get a traditional (not high performance) muffler from an old Cadillac, run single 2" exhaust pipe and put ram-horn style cast iron exhaust manifolds on it. Wrap entire exhaust system in fiberglass heat wrap, insulate cabin of car, especially the firewall, floor and floor of hatch area. Get rid of fancy cam, add skinny tires and discount brake pads, change rearend gearing to 2-something, make sure auto trans has no fancy stall converter or valve body so it slips a lot. Drive really slow. Other option is to spend a year doing an engine swap-my car has been quiet as a church mouse for 12 months. I go out to my garage and all I hear is crickets chirping-it is kind of relaxing and peaceful like a camping trip. My neighbors love it.

[redneck1545]

^^^

 

haha, mine has been quiet for far too many years as well...I wish I could complain about exhaust droning

[Pyro]

I did an exhaust system for a friend with a 350 in his 77 Z.

 

I first went the easy route and built a system with 2-1/2 duals off block hugger headers to a y pipe (dual 2.5 to 3 inch) then to a 3" turbo muffler. The drone was terrible. The worst I ever heard!!! I'm still having nightmares about that drone. crazy droning!!!! Even the exhaust sound outside the car sounded bad. The car was undrivable.

 

So, I put in a H pipe right after the trans then two 12 inch dynomax bullets before the Y-pipe. Now the engine sounds really quiet in the cabin and the exhaust note outside the car sounds really nice.

 

Later, I put in some flex joints right after the headers to reduce vibration from the exhaust system.

 

Got all my stuff from summit racing (mandral bent pipe, mufflers, flex joints)

Edited January 26, 2012 by Pyro

[jasper]

^^^^^^ almost

 

Would like to see how you did it.

Edited January 26, 2012 by jasper

[bjhines]

Mine does not drone and it has relatively free flowing mufflers. The exhaust is loud... but there is no resonating drone.

 

Here is a testing video from it's first runs. http://forums.hybridz.org/index.php/topic/96660-skidpad-testing-video/page__p__908141?do=findComment&comment=908141

 

 

 

 

 

...

[RebekahsZ]

bj-

 

What diameter are your exhaust pipes, 2.25 or 2.5? Whose transmission crossmember did you use? Looks great with lots of clearance, I'd like to copy!

 

Keith

[bjhines]

2.5" dia. That is a JTR install with their entire kit.

[bjhines]

I have seen many modern exhaust systems with Helmholtz resonators near the Mufflers. This is a simple "dead-end" tube of a certain length, tee-ed into the pipe right before the muffler. They are usually around 20"-30" long and the same dia. as the exhaust tubing. They act like speaker tuning ports and use the same descriptive name. Speakers use them to limit the motion of the speaker cone and smooth frequency response. They work the same way in exhaust systems but are used to minimize the pulses entering the muffler and the energy is blocked from escaping the exhaust system with a cap on the end of the pipe.

 

Here.. check out a discussion here.

http://www.performan...hread.php?t=144

 

 

and a paper on the subject of mufflers in general.

http://www.paraglidingteam.nl/PPGTechnics/sound%20and%20noise/Mufflers/1155795969.pdf

 

...

Edited January 27, 2012 by bjhines

[Pyro]

The car is currently at my house but really don't want to jack it up and take a picture.

 

However, we will be pulling the engine out fairly soon to drop in a TPI engine and then I can get a photo.

 

But the narrative should be enough. The Y pipe is at the start of the rear A frame to make room for all the other stuff (flex jonts, H-pipe,and dual bullets).

Edited January 27, 2012 by Pyro

[surpip]

I was under the impression that Helmholtz pipes were used for more fine "tuneing" on the exchaust note, because ive seen cars with those pipes still have a resonator.

[Leon]

I was under the impression that Helmholtz pipes were used for more fine "tuneing" on the exchaust note, because ive seen cars with those pipes still have a resonator.

 

Yes, that's essentially what was already said. All these tubes do is cancel out a certain frequency from escaping the exhaust, thus changing the sound and volume coming out.

[bjhines]

Well... Eliminating a single "peak" in the response is EXACTLY what fixes the cruising DRONE. Helmholtz pipes are the remedy and will allow an aggressive sounding muffler without the interior drone.