Exhaust Resonator Placement

[exhacker]

Ok I need your help once again. I've put my exhaust system together....

-DC Sports JDM 4-1, 2½" collector
-high-flow catalytic converter
-2¼" pipe back to free-flow muffler

I'm going to put an 18" glass pack somewhere in the exhaust system. Obviously, it needs to be behind the cat. But I've been told that haphazardly placing the glass pack will not cancel out the noise properly.

I have access to sound recording equipment, and I'm thinking about taking a recording of the sound.... but I'm not sure where to start. Someone point me in the right direction

 

[chevy302dz]

Don't use glasspacks it's going to sound like shit no matter where it is on the exhaust, especially once it breaks down. Peope don't even put them on V8 domestics anymore.

 

[knowledge]

I would highly recommend not using a glass pack!

 

[posol]

Originally posted by knowledge@Jan 14 2003, 03:48 AM
I would highly recommend not using a glass pack!

seriously- hello and welcome to 1973 when real exhausts came out and replaced glass packs/cherry bombs.

it will sound like utter cow ass, and will not help flow at all

 

[phunky.buddha]

Technically, all the exhaust systems we like to recommend are "glass packs". They're all straight through exhaust systems with perforated pipes surrounded by fiberglass mesh/cubes/whatever. What he's talking about is probably the exact same "glass pack" style resonator that's included in most aftermarket cat back systems.

 

[sportlinecrx]

Originally posted by pissedoffsol+Jan 14 2003, 05:41 AM-->

knowledge

@Jan 14 2003, 03:48 AM
I would highly recommend not using a glass pack!

seriously- hello and welcome to 1973 when real exhausts came out and replaced glass packs/cherry bombs.

it will sound like utter cow ass, and will not help flow at all

LOL

back to the question:
you've got a very good setup. I would get a better muffler instead of the glass pac. Like they said, glas pacs wear out..and they sound horrible. plus...good sounding performance mufflers arent that expensive (usually around $100-$200)

 

[smashed4thgen]

( correct me if iam wrong )actualy i think he is talking about using the glass pack to quiet his exhost by using it as or with his resinator..i was thinking about doing the same because i want my car to sound stock but have good flow for a turbo..ive heard of people doin it before but iam not positive on the application ..

 

[exhacker]

Originally posted by smashed4thgen@Jan 16 2003, 06:57 AM
( correct me if iam wrong )actualy i think he is talking about using the glass pack to quiet his exhost by using it as or with his resinator..i was thinking about doing the same because i want my car to sound stock but have good flow for a turbo..ive heard of people doin it before but iam not positive on the application ..

I'll be using it as a resonator.

[rant]
WHY will it sound like cow ass with a good muffler, high-flow header, and a catalytic converter? WHAT will it sould like (besides vague explitives please)? Give me a sound clip of a car with a similar setup to my proposed!!! Give me some details. I hate these non-descript "flames" that just tell me not to do something, with no logical thought-out reason. Is this how you all move up in this forum?
[/rant]

why do they break down? how fast do they break down?

I'm not trying to improve flow, pissedoffsol, I'm trying to have my car NOT sound like cow ass. My exhaust frightens small children as it is right now, and I'm trying to give it some manners. I realize that my exhaust will not be silent, or even quiet. I don't want it to be like that.... I just want to reduce the resonance, or at least some of the racket at certain RPMs.

If I need to get a cat-back exhaust with a really good muffler to reduce this noise, so be it, but I would rather have Jimmy at the muffler shop weld a $20 part into my exhaust for a carton of smokes and have the same or similar results. I don't have enough money or horsepower to throw a whole lot more than the $700 I already have at my exhaust ($370 header, $20 glass pack, $100 muffler, $200 cat+welding+pipe). I've been told by the guys at Team KLR that I should just "slap it on" (the resonator), but they don't seem to have any mathematical explanation for where to put it, or advice on what it actually does to flow, torque, etc. Looking down through it, I don't see anything (except a little peripheral turbulence, caused by the perforations in the "glass") that would cause an impedance in flow.... I was hoping someone would write a couple sentences about what a glass pack/resonator does to the sound, what it does to flow, and what the good side and bad side is to putting one on.

Take a look at my (small, no ads) website, for pics, and a list of mods. Also, there is a picture of my exhaust without the silencer installed (I can put it on or off in about 30-45 seconds now, 3 bolts).

 

[SolReaver]

ok, i had the bosal cat back on my car (b18b sol) along with an apexi dunk muffler at the end of it

It didnt sound too bad, not too loud at all, and i have no cat. The bosal cat back uses a resonator about 2-3 feet before the muffler

I dont see why you would want to place it before the cat, there is not much room up there in the front

I would use a glass pack placed half way between the cat and muffler. IMO, cars with just a muffler and no resonator sound terrible, very clangy at high rpm (black F&F s2K comes to mind)

Glass packs flow as much as any normal resonator, but quiets out the sound tones. I *highly* doubt they affect flow more than any high quality straight though muffler.

They do break down because the fiberglass inside of it blows out after a while, but big fucking deal, glasspacks are 10 bucks and it takes 10 mins to weld them it. Id say you have about a year before you need a new one.

Good side- cheap effective way of quieting exhaust note. Bad side- minor restriction, but probably wouldnt matter much, and it does wear out after time

Btw, im speaking from experience with this, not what ive heard or anything. I used to work at a muffler shop, and i have a pretty good idea of what im talking about. Keep the cat and add a resonator and you should be fine

 

[chevy302dz]

If you're not very worried about flow then use a stock resonator off a car that has 2.25 inch piping stock. For what you're looking for you will get a better result and it will last much longer. Glasspaks were designed to make stock engines sound like they had power, they are poorly made and when they wear out they sound worse than what you had before. A rough estimate of how long they will last is several per exhaust system.

 

[exhacker]

Originally posted by chevy302dz@Jan 17 2003, 01:39 AM
If you're not very worried about flow then use a stock resonator off a car that has 2.25 inch piping stock. For what you're looking for you will get a better result and it will last much longer.

Thanks! Can I pick these up at a dealership, junkyard, etc? Would a used one work as well as a new one?

-x

 

[chevy302dz]

I would get a new one they are not all that expensive and they are easy enough to get, a dealership, or parts store should have them in stock. And as was already stated just put it in about half way between the cat and the muffler and you should be all set.