Psyte

can someone please explane to me what glass packs are? i keep hearing this word being thrown around on this site all the time. all i can gather is it has something to do with exhaust and better sound.

ZZ28ZZ

It's a cheap tube-type muffler abt 4-5" in diameter. They're hollow and you can see right thru them from one end to the other. Inside there is a tube that runs from end to end with holes in it. Wrapped around the tube is fiberglass matting used for sound absorbation.

They used to be (not sure abt nowdays) avaliable from 12" to over 44" long. The short ones were really loud, and the longer ones were fairly quiet.
The 12" ones were almost exclusively installed by rednecks on their beater pick-ups (along with echo chambers), for the loudest, most obnoxious sound imagineable.

The 44" ones were what we installed on motorhomes and such.

The fiberglass would burn out before long and they would become louder with age. They sounded better than a stock muffler (from the 70's) and most of the hot rodders used them and like their rumbling sound.

By todays standards, they are restrictive (even though you can see thru them).

kfoley

ZZ28ZZ explained that very well. Most people nowadays don't like the sound of them except on a really hot engine. Personally I think they're alright, but I wouldn't want them on my car. I would suggest you get a good muffler (like a Hooker Aerochamber) and use that. They flow much better and sound better too. Of course if you want really loud and little restriction, you could get chambered mufflers, but they're pretty exspensive.

Psyte

cool, thanks for the replys. and lol to the red neck thing

89cmrodriver

i had it on my blazer with a v6 and it sounded really good, loud deep and nice, now if only the timing was set right...but it had a 17in glasspack with no tail pipe it sounded better than any exhaust ive heard so far, sounded good though all rpms..and that was on a v6 that seem to whine at high rpms...lol, ya the ******* thing is prety funny

ZZ28ZZ

I had a set of 26" glass packs on a Pontiac Astre (sp?). It was like a Vega except it came with a 305. Replaced the 305 with a 350 and added the glass packs along with true duals. It sounded like a truck. I'd pull up to a light and notice people looking around for the source of the heavy rumbling.

Once the light changed, they knew where it was coming from.

1FastZ

If anyone is looking for mufflers I have 2 Spintechs in the classifieds section for sale.

82sportcoupe

Out of curiosity, what makes them restrictive? educate me.

btw, my brother used to buy a set of brand new glasspacks and throw them in a fire to burn out all of the fiberglass. What a weirdo. lol

Ricktpi

The center core is necked down to a smaller pipe that is restrictive.

82sportcoupe

hmmmm.. learn something new every day. how much smaller generally is the center core pipe compared to the intermediate pipe (header/manifold to muffler). I was under the impression that the inner diameter of a glasspack was the same as the inner diameter of the intermediate pipe. basically like having a straight pipe. that doesnt make any sense why they would make them like that.

I have been educated!

Momar

Well, I have dynomax bullets on my car. I think that they are considered a type of glasspack. They dont neck down inside like you describe though. I used them because it was about the only thing that would fit. I think it sounds nice. Are these actually restrictive even if they dont neck down inside. They are supposed to be race mufflers so I wouldnt think that they would be. I think I have read that some glaspacks also had louvers inside that directed the air through the fiberglass on the outside. I know that this style is supposed to be real restrictive. I have sound clips in the sig. It is hooker long tubes into duals with h pipe and dynomax bullets and then turndowns.

Ben

89IRO

Can somebody answer Momar? I'd like to know too. -89IRO

Psyte

dude, that sounds SWEET!

kfoley

Hey Momar, how loud is that setup and what size pipe did you use? I think that's the setup I'm going with when I drop in my 406. Right now I have a dual hooker setup that I'm going to sell when I get my motor, so if anybody wants a complete system (headers to tailpipes) let me know.

Momar

It is pretty loud, especially outside the car. Inside it isnt to bad. I havent got the car out to where I drive it much yet. I just finnished fixing an oil leak in the oil pan and changed timing covers. I still have to put all the accessories back on and am installing a LT1 140 amp alternator, and LT1 starter on it while I have it appart.

It is dual 2.5" w/ h pipe and bullets. It doesnt seem to be that loud in the car but I have only driven it a few times around the neighborhood checking to see if everything was working right so far since I have changed so much on the car in the last year while it sat in the garage.

Ben

Air_Adam

Glasspacks that are do a 'reasonable' amount of muffling usually have an inner tube diameter of 1.75" or less... thats why they are so restrictive.

Karm

Like everyone said, they are like cheap mufflers and burn out over time.. not too bad, but they do get louder.

Shorter glasspacks will tend to pop when you let off the thorottle, and they are really loud. Longer ones like 18" or more are recomended for most vehicles. The longer they are, the quieter they are.. well, I guess they get deeper but not quieter.

A lot of hot rodders choose them for the sound, Ford Flathead V8s and Y blocks sound great with the appropriate length glasspacks, Smithy (pronounced Smitty) is the retro glasspack of choice for rodders.

Glasspacks are considered an old retro performance sound, while Flowmasters are considered the modern sound of performance.... but they are also 5 times more expencive.

Some glasspacks like Cherry Bombs are what gave glasspacks a bad name. They are restrictive and pretty much suck unless you are a red neck.
Some glasspacks have a smaller inner core like others have said, while some are the same size as the inlet.
There are various inner core pipes, you can get everything from perforated (just holes) to louvers.. a good rule for louvered packs is openings facing the engine will tone it down while holes facing the rear end will not. Then there are all kinds of inbetween designs.

I have a 1952 Ford F-1 with a flathead V8. I will be getting the exhaust redone from the manifold to the tip... 1 3/4 inch true duals with 22" glasspacks just before the bend for the rear axle... with chome tips sticking out under the tail gate, spitting the exhaust straight back. I expect it to be loud, deep, and unbalanced... pretty much like a '50s hot rod would sound.

Hope that helps.

raggedout91RS

I just installed a thrush glasspack on my car that was 28" in length. The inner core doesnt neck down and it is only perforated, no louvers. I even had to cut 4" out of it to fit and then welded it back together. It has a deep tone that is,nt too loud, outside the car that is.

rsscoty

We used to run glass packs on our beater trucks when I was in high school for the sound. And even though they are restrictive, any dual set up is better than the single exhaust.

One of our tricks was to pour oil in them before we put them on. The oil would heat up and burn the 'glass out faster, or we would get them red hot and spray water in them to bust the glass.

They sound pretty cool when your 17 back in the 70's and early 80's. I wouldn't dream of running them now, because they are so restictive.

raggedout91RS

Hey rsscoty how did you bust finely stranded fiberglass hair? You do know that is whats in those g-packs right?

mike1986fyrbird

LOL, they arn't restictive!

mike1986fyrbird

I got one on my four-banger turbo and it sounds like a Weedwacker, Chainsaw, and a pissed off bumbo-bee dependign were the throttle is at.

mike1986fyrbird

They flow about 510cfm.

Error404

Glasspacks "burn" out alot faster when you flush cold water down them they they are good and hot

Yea... I am from Louisiana... and I had a truck... you can let your imagination run wild... but I graduated to a 3rd gen... so I'm now "white trash"? LOL!

Psyte

anyone got pics of installed glass packs?

Error404

A glasspack would basicly take the space of a strait pipe. How much pipe? that depends on how long of a glasspack. The glasspack looks like a 4-5 diameter pipe, with 3 inch ends. Not much to look at really :lala:

Berlinetta00

I really resent (resemble, same thing right?) those comments about the glass packs on the beater trucks with the rebel flag hanging out of the back. Im just going to say this for the benifit of all you educated people out ther. The AHTBA (American Honkey-Tonk Bar Assosiation) recommends this tratment of the family truck, and many a beer has been consumed on my tailgate admiring the sound of a five year old cherry bomb that has been installed on countless vechicles. I must say that I will never stoop to the high-class style of a real exhaust system that actually extends more than 12 inches from the rear of the cab.

From where Im sitting (10 feet up in my big 'ol truck) it's the only way to fly!!!

firechicken_-54

my brother used to have a 17-20" cherry bomb, on his accord
we poured gas in it and while reving it up he lit it on fire the flame shot back about 3 feet he did this because some idiot said it would soundbetter got to annoying past 5 k

Error404

Yea, that is the same (different approach tho) as flushing cold water down hot glasspacks. It gets rid of the fiberglass inside, so you basicly have a strait pipe. Yea, I think that would sound like crap on a honda. (and some might say the same for a V8... but not me)

Shagwell

To Momar - yes, a bullet is considered to be like a lasspack, but only in form. A bullet muffler is much better. Very little if any restriction from a bullet. They are both straight through designs, but a glasspack uses the perforated tube and the louvers. Bullets are straight through, same size perforated tube that is wrapped with a couple layers of fiberglass, then given the slightly larger shell in the center to cover the glass.

Same concept, way different results. The bullets are also usually louder, but have a cleaner sound.

later, justin...

ajm_shorty

How are you guys Shooting Water and Fuel down the glasspack?
Also I'v Heard about Flame thrower exhaust using a spark plug? can someone tell me EXACTLY how this is done???

Error404

how to shoot water down the pipes? Well, I just hacked off the piping right after the glasspacks, drove the truck around for 10 minutes, floored it on the way home, and already had a water hose set out, and flushed some water down them. Steam went everywhere, (keep the engine running, you don't want water to get to far up the pipes... right?

Flame thrower exhaust? Probably 2 ways.

1. Have an actual flame thrower in the tips.

2. Have some sort of spark mechanism (spark plug?) in the tail pipe, and set the carb to run real rich., or have some fumes some how diverted to the exhaust pipe tips.

Psyte

burning out the guts of glasspacks doesnt sound like a good idea to me. why not just use straight pipes? its probly alot cheaper to just use a regular pipe than to buy one of these things and burn it out right? why doesnt everyone just use straight pipes anyway, is there a point to haveing mufflers?

jfawcett10

LOL, I had some Purple Hornies on a truck I had....

rsscoty

Growing up in Oklahoma, we didn't have any emissions laws but there were noise restrictions. It was illegal to run with out mufflers of some sort. We would get the glasspacks, burn them out, then if the cops wanted to look...Hey we had mufflers

Air_Adam

Actually, glasspacks don't sound too bad on some imports... a friend of Karm's and mine had a glasspack installed on his Tercel, and it sounds pretty cool. It is louder, but it IS NOT a fart can... It sounds really deep and throaty, and is still very quiet at idle speed. Not sure how long it is though.