Glasspacks

[ShutUpHippie]

Does anyone know about the real advantage to glasspack mufflers?? Obviously they are loud as hell, but as far as performance goes...

My Blazer came with them on it, and I was just thinking that I know nothing about them except they wake people up when I drive through neighborhoods at night, haha! I like them, but I can definitely tell the difference (the sound is enhanced) between those and my friend's 3" flowmasters.

[Funrover]

There really isn't an advantage to them over a good muffler.

[ShutUpHippie]

I figured as much. I do like them for the most part, although sometimes I feel like "that guy in the big F350 diesel" that no one can hear through the window unless the truck is off. :lol:

[ShutUpHippie]

Does anyone happen to know how a glasspack muffler works?

still learning...

[ShutUpHippie]

Nevermind, I guess I could have looked it up: Glasspacks are an old, simple, and relatively inexpensive design. They are very effective at reducing back pressure, but not very effective at muffling noise. Thus, they preserve more of the engine's power while sounding louder than conventional mufflers. -Wikipedia

[Funrover]

Nevermind, I guess I could have looked it up: Glasspacks are an old, simple, and relatively inexpensive design. They are very effective at reducing back pressure, but not very effective at muffling noise. Thus, they preserve more of the engine's power while sounding louder than conventional mufflers. -Wikipedia

They also save space.. such as for rock clearence

[ShutUpHippie]

Yeah, they aren't very big. My friend (who is about 5'4") can sit up under my truck.. . not as worried about hitting rocks- unless they are BIG. My receiver hitch oughta catch those.

[Funrover]

Yeah, they aren't very big. My friend (who is about 5'4") can sit up under my truck.. . not as worried about hitting rocks- unless they are BIG. My receiver hitch oughta catch those.

So when are you gonna be back for wheeling that rig?

[ShutUpHippie]

Come back from TX next Saturday! I can't wait to get out of here!! There are so many people and it's hot. AND THERE ARE NO MOUNTAINS!!!!!!!!

Can't wait to pull the sway bar and take it out. :D

[Roostercruiser]

cherry bombs are really cheap around 25 bucks and sound good . thats what im gonna put on the burban but i keep forgetting for 3 years now.

[Swath]

I'm not arguing for one side or the other. There are those that believe some amount of backpressure in the exhaust improves low end and mid range torque. A pure open pipe, like when you see 8 straight pipes sticking out a race rig's hood, is how you make big top end power, crappy low end torque, but hi flow for maximum top end HP.

Conversly, it is said that when you get "too much free flow" you hinder your low to mid range torque. The theory is that the "proper amount of backpreassure" will increase low end torque by helping seal closed exhaust valves.

When I built my 460 there were numerous recommendations telling me I would get better bottom end and midrange power by plumbing the exhaust into a large single pipe rather than dual exhaust. In addition "they" warned about putting on too free flowing of a muffler for the same reason. I put on a very free flowing muffler on a single pipe system and routed it out in front of the rear tire, when I took that sucker off road the thump of that motor bugged my old ears something fierce, the reverb bouncing off the rocks and such was impressive but mind numbing after a long day on the trail. So I put a quiter muffler on and relocated the exhaust to behind the rear tire instead of in front.

Knowledgable folks on the Sami tech forums speak of the same things, too much free flow reduces torque on the bottom and midrange. Torque in a Sami 1.3? well it's all relative I guess. Built 460 ford = big torque, built 1.3 suzuki = squirel chatter. :)

Lots of folks advise to use at least and H or X crossover connection between the two pipes in a dual exhaust system for similiar reasons. There are forces at play in the exhaust pipes that are not fully understood by me. I do know that for my applications I do not need the full bore free flow required to get the most HP at the top end. For off roading/in town driving/towing I do want to optimize my low end and midrange torque so I get conservative with my exhaust pipes and reduce the volume. Headers too, 4 pipes to a single collector is best suited for top end power, a tri Y type setup is better for low to midrange torque.

In your case? If you like the noise floor it and have fun, if big noise is not important to you, you might be able to increase you bottom and mid range torque (slightly) with the right exhaust setup (crossover pipe and slightly quiter muffler). You can go too far in either direction, tune your setup to your specific needs.

Am I still talking about Glasspacks?

Just some food for thought. :2c:

[ShutUpHippie]

Well for now, they are gonna stay because I don't have much free-flowing cash.. they are a little loud sometimes, but most of the time I enjoy them. I guess I can see how it might be a little much on a full-day trail run.

We'll have to see on the next run I go on: how many people don't want to hang out with me at the end of the day.

Plus, I don't really know what kind of setup I would get if I changed it.. does anyone with small block 350 knowledge want to add anything?? :wrench:

[Funrover]

What do you want to know, small block mods are more than prevelant!

[Patrolman]

When I had my old 74 Scout with the 345, it had duals with the tips right behind the doors. Had glass packs and it was LOUD. Best thing was to pull up next to someone you were joking around with and throttle it with the pipe pointed right at their window. :) Super loud though when driving it. If it empties out the back it isn't nearly as bad.

Downfall to having glass packs now? Denver has a noise ordinance they are getting more strict about. I think it might be a $100 fine.

[ShutUpHippie]

I suppose what everyone's favorite exhaust setup is, and why? I have been thinking a little about changing mine eventually, but like I said earlier, once cash-flow allows.

What's the law? That would suck, haha.

By the way, mine comes out both sides right behind the rear tires.

[Funrover]

I would do duals with a "X" pipe set up and 2 good high but not full flow mufflers.. IMO of course

[Swath]

I would do duals with a "X" pipe set up and 2 good high but not full flow mufflers.. IMO of course

X2, might get expensive if ya gotta run a cat (x2) though.

[ShutUpHippie]

Don't have any :thunb:

[Swath]

Don't have any :thunb:

Cool beans, my 84 3/4 ton ford was exempt from needing a cat, major plus in my book.

[colomil]

The exhaust design that yields best power is one that flows well and doesn't let the exhaust gases cool too much on the way out the pipe. Headers will make more of a difference that any other component in the exhaust. Glasspacks maintain the velocity of the gases but absorb the pulses via the fiberglass packing (this is what high perfomance motocross bikes use). There are good mufflers out there that flow well and sound much quieter. For a 350 chevy I would recommend using shorty headers and dual 2.5" pipes with a turbo muffler that exit before the rear wheels. Higher performance would call for larger diameter pipe.

[Funrover]

Have not even started the Header part yet. Hedmen does a nice set of shorty headers.

[Patrolman]

I suppose what everyone's favorite exhaust setup is, and why? I have been thinking a little about changing mine eventually, but like I said earlier, once cash-flow allows.

What's the law? That would suck, haha.

By the way, mine comes out both sides right behind the rear tires.

The law is based around the decibels. Unsure of the upper limit. It was really intended to give tickets to Harley's that are too loud, but glass packs would likely fall into that same category. Just don't drive through Denver proper.

[Swath]

I use Doug Thorley Tri Y headers on both my 7.5 and 1.3 motors.:wrench:

[ShutUpHippie]

Not really sure at the moment about emission testing.. but I'll look that up here soon enough- I am registered in Gunnison for now, so I'm good.

[Whitey Jr]

I figured as much. I do like them for the most part, although sometimes I feel like "that guy in the big F350 diesel" that no one can hear through the window unless the truck is off. :lol:

now i feel bad about driving my work truck and trailer home 2000 f450 and a 26ft trailer

[ShutUpHippie]

haha

[Whitey Jr]

what can i say i have the laudst rig on the block my jeep with a muffler with no innards so they might actually appretiat the truck being there

[Brody]

I would do duals with a "X" pipe set up and 2 good high but not full flow mufflers.. IMO of course

Same here if you don't have to have more than one CAT. If you have to have two, then run a single out of the collector. A free flow and mufflers, 2.5" piping.

Don't bother with the glass packs. They are just loud and offer no more advantage than a free flow muffler...plus the loudness will be really irritating after awhile..and irritate everyone else, too. They are junk...

[gm4x4lover]

Best thing you can do on the chevy's is 2 1/2 in to 3 then run them through a good flow, dynomax, or similar type muffler. If you have to register in Denver or surrounding areas you will need the cat back on. Modern high flow cats do flow better than the older factory style cat on that truck.

To little back pressure on your blazer steals low end torque and gives you less fuel mileage. The best setup i have found is a summit high flow cat and a single 3" flowmaster 70 series muffler. sounds great and isnt to loud outside and little to no resinence inside.

The other problem with running duals under those trucks is the lack of room to run the pipes. Typically they run them under the t-case cross member. It leaves the pipes vonerable to be crushed and bent.

[1freaky1]

Im running headers plus a glass pack on the 98 ranger and a Raptor muffler on the 02 Ranger hoping to put headers on it sometime in the future just so darn expensive for rangers.

[WINKY]

im straight piping the diesel. HAHAHAHA

[Brody]

Best thing you can do on the chevy's is 2 1/2 in to 3 then run them through a good flow, dynomax, or similar type muffler. If you have to register in Denver or surrounding areas you will need the cat back on. Modern high flow cats do flow better than the older factory style cat on that truck.

To little back pressure on your blazer steals low end torque and gives you less fuel mileage. The best setup i have found is a summit high flow cat and a single 3" flowmaster 70 series muffler. sounds great and isnt to loud outside and little to no resinence inside.

The other problem with running duals under those trucks is the lack of room to run the pipes. Typically they run them under the t-case cross member. It leaves the pipes vonerable to be crushed and bent.

I went from duals with headers and a 2.5" with crossover to a single collector into a 3" muffler, then 3" out on a Ford I had with a trick over bored, yada, yada, 400 in it and the difference was impressive...good seat of the pants boost, better low end, better mid range and better upper end. Running big engines, you cannot be too concerned with gas mileage or you wouldn't have them to begin with, you would have a 4 or 6 cylinder to start with.. better gas mileage and big engines is oxymoronish ...it don't work...
I never checked what mileage I was getting either before or after...cause I had a big engine...what was I gonna gain, anyway? .0013 better mileage??

[4wdhunter]

I agree with Brody, the increase in mileage would be miniscule if at all. I've had them on a few different rigs and all it did was make them loud as hell. Whoa, did I just say that, I must be getting old.

[ShutUpHippie]

im straight piping the diesel. HAHAHAHA

You oughta get some stacks for that thing. Get the kind with the flaps on top so when you rev the engine, they flap up and pour out smoke! :thunb:

[WINKY]

lol yeah that is a few bucks i dont have.... i wouldnt mind sticking the exhaust right out the hood....


http://images.google.com/imgres?imgurl=http://i204.photobucket.com/albums/bb25/cumminsontherocks/120207009.jpg&imgrefurl=http://www.cumminsforum.com/forum/show-time/37835-hood-stack-4.html&usg=__RET8lt8jnZGiIbmGvwiiDAYUUBQ=&h=768&w=1024&sz=393&hl=en&start=14&tbnid=6p0eBwhcuoZHQM:&tbnh=113&tbnw=150&prev=/images%3Fq%3Ddodge%2Bram%2Bhood%2Bstack%26gbv%3D2% 26hl%3Den%26safe%3Doff%26sa%3DG


I just noticed, read through all the pages check this beast out... hes from sanford florida bout 40 minutes from wherre i lived....HAHAHAHAHA

[ShutUpHippie]

Do it! I'll help cut holes. :wrench: