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All those kinds of mufflers flow the same. Maybe not if u test it with scientific equipment, but for all intensive purposes, a car that is gonna run those, will flow PLENTY. they do almost nothing to make the car quiet. They all flow like an open pipe. Heck thats prety much what they are.
I used to run thrush glasspacks off of my hedman longtubes.
The glasspacks sat directly underneight the front seats, and it was pretty loud, but managable. Kinda hard to talk sometimes. It could get annoying though here and there, depends on your taste.
I didn't have anything after the glasspacks, they basically came straight off the hedders, so make sure you finish up the rest of the exhaust system, and dump the pipes out the back. It'll be a lot "quieter", well inside at least.
I had added 2 4ft sections of pipe to the glasspacks, they ended right at my 10 bolt. That was very nice and comfortable, compared to "sitting" on them. Just as loud, but the sound exited out the back.
... Now I'm running a 3in flowmaster 80 series catback, and i love it.
__________________ 1987 Chevrolet Camaro Sport Coupe-assorted shades of rust 13.75@102.2mph on 2.1 60'
"rust rocket" ...someday hope to install FAST EZ EFI... 1999 Chevrolet Camaro Z28-Artic White, Flame Red Cloth Full Bolt-Ons, Tuned by Frost, Hurst Billet, Bilsteins, Zr1s
Now any difference between those mufflers I mentioned ? I had read something about those ones that had louvers inside them flowed kinda crappy while the perforated center ones flowed alright ?
I don't know about most of you guys' experience, but my daily driver has a thrush with a perforated core, although its a v-6 it's very much quieter then when i ran it with the open pipe. It's got a very deep rumble almost like a v8 and it has that classic glass pack sound upon throttle. The sound is so deep that it carries for a way to. Yes the ones with the louvered core don't flow as well, but flow better than stock. I've heard others say that glasspacks don't flow well and i'm sure some on this site agree, but then again it's straight through, therefore NO mufflers would flow well.
I friend of mine has the purple horny mufflers attatched directly to the headers, and the mufflers dump downward. Thats the whole system! No cats, no over the axle exit. It sounds really good like a 60's muscle car sound.
Assuming you are just replacing the muffler and the cat will still be in place (since I see "San Diego" in your info), it shouldn't have the poppy sound so common with open-type mufflers.
The biggest issue I have with those types of mufflers is the core is typically smaller than the inlet/outlet. So, they usually actually flow less than a chambered/baffled performance muffler of the same inlet/outlet size. Of course, with an LO3 that may not be much of an issue.
Personally, I think my 80-series Flowmaster is more than loud enough. I'd rather have it quieter, actually.
uh, yea, maybe i'll be the first to say it then:
purple hornies, cherry bombs, thrush, etc etc, all glasspack mufflers, flow poorly. Very poorly.
Why the heck else would they be $20????
They sound great, but flow is poor. Flowmaster just quietens it down a bit, and flows a bit better. Dynomax flows the best, look at the flow charts, they're one of the only companys to post that, however, they aren't very loud.
I'd like to see some dyno runs with various mufflers. It would definitely give me some stone hard facts on mufflers. Maybe then i won't argue with people how poorly flowMASTERS flow, id just show them the papers. Sorry to affend those who run flows, just pokin fun, infact my car has a single super 40 on it now.
Originally posted by Sonix uh, yea, maybe i'll be the first to say it then:
purple hornies, cherry bombs, thrush, etc etc, all glasspack mufflers, flow poorly. Very poorly.
Why the heck else would they be $20????
That's like saying "straight pipe doesn't flow well becuase its $10 for 3 feet of it".
well yea ok, based on straight through design, they *should* work the best....
but from what i've heard, it seemed to be common knowledge, that they were loud, but not great for flow... I mean *******s put them on 'cuz they're loud and aggressive sounding... (no offense to anyone, I was going to use them)...But apparently they don't flow great.
certainly, there are people who "think" they flow poorly, but i have yet to see factual information on it and i've spent hours doing searches on glass pack flow charts in comparison with other common brand mufflers and have found nothing. I do however see that the downsized core would restrict airflow at high rpms, but i don't see how turbo style or flowmaster s flow any better being that their is the restriction of changing directions and baffling in the direct path of flow. I have an open mind and would like some facts to straighten out whether or not i'll ever use them again.
All mufflers create turbulance thats how they deaden the sound.
Actually Ive put cherry bombs on several different cars and trucks over the years. The last truck I put one on was an 81 GMC, it was a factory system with cat that had seen one backfire too many and the muffler was exploded. I used a 26in cherry bomb and the thing was as quiet as the stock muffler. If you look at the glasspack designs they are all different. As long as you find one witout the restrictor plate which looks like a little windmill blocking the inlet side and the pipe seems descent it will flow just fine.
__________________ 1976 SWB C10 3/4 drop, gen VI 454/M3.
1973 Buick Apollo wifes play car. Chevy 383/S3.
Originally posted by Sonix uh, yea, maybe i'll be the first to say it then:
purple hornies, cherry bombs, thrush, etc etc, all glasspack mufflers, flow poorly. Very poorly.
Why the heck else would they be $20????
They sound great, but flow is poor. Flowmaster just quietens it down a bit, and flows a bit better. Dynomax flows the best, look at the flow charts, they're one of the only companys to post that, however, they aren't very loud.
This is possibly the most ridiculous post I have EVER read in the exhaust forums. Or any of these forums!! It was even worse than therckid's posts!!!
Those are all straight through style mufflers, they have the BEST flow of almost ANY type of muffler. in fact they aren't even mufflers so much as they are simply reasonators. The only things that outflow them are most likely true reasonators - dynomax bullets, slp lm, borla xr-1, etc.
And flowmaster is the WORST OF ALL AFTERMARKET BRANDS!
If you include dynomax bullet mufflers ($35) in your list of poor flowing mufflers, then let me tell you this. In back to back 1/4 strip testing my car went EXACTLY the same times with an open y-pipe as it did running the bullet muffler to over the axle exits.
And the reason they're so cheap is because they're very inexpensive to make. All they are is a peice of tube with different interiors. It's very simple and cheap. The reason no one runs them on the street is because they're LOUD. And they don't do very much toneing so in the end it still sounds like open headers. People will pay alot more money for less flow, but better (an objective opinion - I like LOUD personally) sound/tone quality.
One of your links was some obscure email, another was an article about heads that vaguely mentioned glasspacks but in the end the guy used a glasspack anyway, and the other was some non-credible forum full of wanna be boy racers. Find some hard proof and post it.
That was the biggest bunch of r!cer bs logic I have yet to see on these forums. Like was said above, would you say that 3 feet of pipe flows poorly because it costs $10 bucks? If you do then what the hell are you doing working on cars? You scare me.
Sorry for the rant folks but it was incredible to see this kind of logic at work and I needed to post up a retort to that in case a newbie was to read this thread and take his post as a truth
Last edited by urbanhunter44; 12-19-2005 at 02:19 AM.
Turned into a heated situation while I was gone. Well bank problems prevented me from ordering a muffler right before I left so I still have to get one.
"Poppy" sound, do you guys mean the classic "uneven" rumbling sound ?
Two questions did pop up for me now:
1) Perforated core vs. louvered, which one's louder ?
2) Thrush glasspack vs. Purple Hornies, which one flows better ?
The pipe diameter after the cat converter, is .. 2 1/4 or is it 2 1/2 ???
Well problem is this .. I honestly don't know how they sound compared to each other .. I had t ocut the exhaust so running straight after the cat right now, sure I LOVE it, but it's too loud to be legal *sigh*
I may go with the Thrush I guess, considering I'll hopefully finish the damn ram air thingy I've been S L O W L Y (i.e. read working way too slow) designing, that thing will make it louder anyway
Originally posted by Sonix
Interesting tests...I noticed a 2.25" round glasspack showed 133cfm (louvres), to 274cfm (non louvred), while a dynomax super turbo showed 268cfm....
How about use the same pipe diameter as reference. The dynomax is 2.5".
The "poppy" sound they're talking about has to do with the fact that adding a straight through muffler will reduce the amount of backpressure and increase flow. When this happens more unburned gas enters the exhaust stream because it's still running on the same tune. This has adverse affects, ranging from burning out O2 sensors and catalytic converters (extremely rare on stock/near stock thirdgens) to the popping noise caused by the unburnt gas in the exhaust stream expanding rapidly as it exits the heads.
The way to correct the popping noise is to get a proper tune for your vehicle using a wideband O2 sensor to get your air to fuel ratio. You will gain power by making sure your air to fuel ratio is proper as well.
The popping is annoying, but not harmful for a near stock thirdgen.
And I don't think it's legal in any state in the union.. except maybe Texas However I roll around 24/7 like this and have yet to have a cop say anything other than "She sounds good."
Firebirdjosh:
Ram Air directly will not make anything louder, except a sucking noise will be able to be heard under hard acceleration. However indirectly what will make the exhaust louder and cause a tone change is the increased air (thus increased power) entering the motor. More power = louder exhaust.
Last edited by urbanhunter44; 12-19-2005 at 08:41 PM.
The "poppy" sound they're talking about has to do with the fact that adding a straight through muffler will reduce the amount of backpressure and increase flow. When this happens more unburned gas enters the exhaust stream because it's still running on the same tune. This has adverse affects, ranging from burning out O2 sensors and catalytic converters (extremely rare on stock/near stock thirdgens) to the popping noise caused by the unburnt gas in the exhaust stream expanding rapidly as it exits the heads.
The way to correct the popping noise is to get a proper tune for your vehicle using a wideband O2 sensor to get your air to fuel ratio. You will gain power by making sure your air to fuel ratio is proper as well.
Some what true so I'll leave it. If you place the glasspack after the cat in lets say the stock muffler posistion all the unburnt fuel will be plenty burnt and will have no effect on 02 readings. Of course with a 3rdgen with it's upstream 02 this has no effect at all.
I dont know what mufflers have less back pressure, I would look for the most horspower the mufflers make. Less back pressure doesnt mean more horspower. On my drag car I ran 4" bullets and the difference between open headers and mufflers wasnt much in the timeslips. can anyone find dyno results with different mufflers?
Originally posted by SSC Some what true so I'll leave it. If you place the glasspack after the cat in lets say the stock muffler posistion all the unburnt fuel will be plenty burnt and will have no effect on 02 readings. Of course with a 3rdgen with it's upstream 02 this has no effect at all.
Haha I havn't owned a thirdgen in so long.. I'm getting used to my T/A.. I've burnt the sensors out TWICE! Then I got it tuned
Originally posted by NHRA427 I dont know what mufflers have less back pressure, I would look for the most horspower the mufflers make. Less back pressure doesnt mean more horspower. On my drag car I ran 4" bullets and the difference between open headers and mufflers wasnt much in the timeslips. can anyone find dyno results with different mufflers?
If you search in the achrives there was a thread that had actualy dyno and bench flow numbers. But different setups react different to every muffler.
Originally posted by SSC If you search in the achrives there was a thread that had actualy dyno and bench flow numbers. But different setups react different to every muffler.
People used to link a 'Stang site that tested a bunch of different mufflers on the dyno. I don't recall if Cherry Bombs were part of the mix. Borlas were 2nd best after Warlocks uncorked, which were better than the headers open at the collector.
It is true that different systems will react to different mufflers in different ways. For the purpose of the originator, though, it probably doesn't make much difference.
"Popping" sound: Straight-through type mufflers have a tendancy to pop or crackle pretty loud under load. I had a pair of 3" Dynomax Bullets with 2-1/2" tailpipes on the 396, it was fine at idle and cruise, when I needed to pull away from a light or stop sign, or pull into the driveway Fridays after midnight after a night of racing I was afraid of upsetting the neighbors with the crackling it went into. But, in your setup it probably wouldn't be that loud or harsh.
Story about Cherry Bombs: Fellow racer with '68 Camaro 327 4-speed, mild upgrade cam & intake, long tube headers with Cherry Bomb header mufflers and short tailpipes ahead of rear tires, ran 14.4's (up at our 5800' altitude). I gave him a pair of 2-1/4" Pacesetter turbo mufflers, he started running 14.2's.
My 4" bullets didnt cackle at all. they were straight off the collectors. But my boss has cherry bombs on his elcamino and they cackle like crazy, I hate it. LOL
Originally posted by SSC If you search in the achrives there was a thread that had actualy dyno and bench flow numbers. But different setups react different to every muffler.
Geeze, I hate when I see soo many misspelled especially when it me doing it.
I want LOUD but I don't want to see the fancy blue/red lights behind me either 
The dynomax is 2.5". 
However I roll around 24/7 like this and have yet to have a cop say anything other than "She sounds good."
If you place the glasspack after the cat in lets say the stock muffler posistion all the unburnt fuel will be plenty burnt and will have no effect on 02 readings. Of course with a 3rdgen with it's upstream 02 this has no effect at all. 
