In my observation, I see glasspacks usually near the end of an exhaust system, especially in race cars that are required to have a muffler.
I've seen a few threads on here (but haven't been able to find) where people ask about putting a glasspack in place of the catalytic convertor. and I've also seen many saying its not a good place for it?
is there a specific reason?
I am currently running a straight pipe system. I had a muffler shop delete the cat, and eventually the muffler when its case exploded. so everything it OE routed.
its only terribly loud above 3500. but I'm already getting bored with the novelty of rebellious sound. and now I have some cash set aside to spend on experimenting. glasspacks are incredibly cheap, especially the larger ones. (I found 8 inch bodies for 50 and 24 inch ones for 25)
Or leave the cat on, as a properly functioning cat on an engine made in the last 30 years does not slow it down, and it cleans out an enormous amount of pollutants that end up in the air that we all need to breathe. It is rather annoying sitting in traffic behind some immature racer-wannabee driving a Civic... (or Fiero) who removed the cat for some imaginary gain, while stinking up the air and causing people behind you to be breathing in excessive fumes.
Removing a properly functioning Cat is a waste of time, creates unnecessary pollution... for what benefit?? If you want to go fast, maybe put in one of those engines that you have been talking about for years..
Or leave the cat on, as a properly functioning cat on an engine made in the last 30 years does not slow it down, and it cleans out an enormous amount of pollutants that end up in the air that we all need to breathe. It is rather annoying sitting in traffic behind some immature racer-wannabee driving a Civic... (or Fiero) who removed the cat for some imaginary gain, while stinking up the air and causing people behind you to be breathing in excessive fumes.
Removing a properly functioning Cat is a waste of time, creates unnecessary pollution... for what benefit?? If you want to go fast, maybe put in one of those engines that you have been talking about for years..
+1 to what he said. Keep that cat. Don't do dumb things to the exhaust just because you think it's "cool".
Originally posted by AL87: its only terribly loud above 3500. but I'm already getting bored with the novelty of rebellious sound. and now I have some cash set aside to spend on experimenting. glasspacks are incredibly cheap, especially the larger ones. (I found 8 inch bodies for 50 and 24 inch ones for 25)
Install a proper replacement cat and replacement muffler, for the car.
the old one rotted away, a replacement is not on my list. and my state isn't emissions controlled, so I think i'll save my money. I blew up the old muffler, and that isn't on my list either. the car is however a little louder than what I'd like, I'd like to maintain a conversation with my windows down in stop and go traffic otherwise it never gets loud if I drive conservatively at 1/4 throttle under 3500.
the 2.8 is going to get a custom 290 cam. and at idle it'll sound sweet. not saying that the comp 252 I had didn't do a good job at a 700 idle rpm but I'm looking for more chop. Im sure with the long glass pack in place of the cat, it should sound fine.
my main point was to find out wether or not to actually put it there, or behind the tips... since that is what I see. is the sound going to get louder if its in place of the cat? who knows... I'll find out in a couple of months.
So you are going to waste more time and money on a 2.8, just like you did on the 2.5? What was the point of all the endless posts about 3800 SC, Turbo, LS4, etc?? Just fishing for useless info?? If you have the money, then put a proper exhaust on the car that includes a muffler and catalytic converter. They were both invented for a reason, and...guess what... appear on ALL high performance cars built in the last 4 decades. With the glass pack and fancy cam, you will still lose a race to my wife's Toyota Sienna full of 3 kids, toys, and the A/C turned on. So why bother??
If I was your mother, I would bitchslap you 4
[This message has been edited by cam-a-lot (edited 03-09-2014).]
When a cat goes bad, I replace them with a straight pipe. Your key words there was functioning correctly. They clog up pretty easily when theyre old and some people dont want to spend $200 on a new one if you dont need to. I had a nearly new Lincoln Town Car I parked in the yard once. It caught the grass on fire under it. Luckily I noticed it pretty quickly and had no damage. I had true dual exhaust installed a few days later with no cats and no more problems.
You can get a catalytic for a lot less than $200. Yes, I could also dump my used motor oil in the ditch, or bypass the sewer and let my toilet run straight to a lake to save a few bucks, but it doesn't make it right. A catalytic converter removes an enormous amount of pollution from the environment with no performance loss.
Holy crap, I didn't know Fiero owner where a bunch of tree hugging liberals. He asked if anyone has info on how is the best way to do the mod he wants, not on how you feel about global warming. So quit high jacking his post. If you want to talk about environment stuff then start your own thread that isn't in the "Tech Questions" forum. Just saying.
There is no "best way". It is a friggin muffler clamp or weld. What is there to discuss in that case? Any idiot can figure out how to replace a catalytic converter with a glasspack if the technical details were the only issue. I was only commenting on the practicality/logic of it all. Nothing to do with "liberals". I am as conservative as they get, but it doesn't automatically mean that I want to dump antifreeze in the local creek just because I can get away with it. Some of us conservatives actually have an education and a brain.
Back on topic I would say it would be better than just having a straight pipe. You need something to there to create a little back pressure. There was a good thread on here that I read recently talking about the exhaust cycle and needing something within six feet of the y pipe to break it up. The muffler in stock location is just pass six feet. car will run better with something there.
You want to break up the exhaust pulse at the CAT location. I have used the Magnaflow and the Morosso mufflers in the CAT location and they sound great.
However, the straight through design like the Magnaflow does not break up the pulse. I tried the Turbo muffler and lost torque.
On balance, the best performance was from the Moroso which as spiral baffles, but, it was too loud for my neighbourhood.
Probably a Flowmaster 40 would do the job in both ways, cut the decibels and break up the pulse.
In short, a glass pack will sound ok but you will lose torque at that location due to the overall length of the pipe
You can get a catalytic for a lot less than $200. Yes, I could also dump my used motor oil in the ditch, or bypass the sewer and let my toilet run straight to a lake to save a few bucks, but it doesn't make it right. A catalytic converter removes an enormous amount of pollution from the environment with no performance loss.
You can get a brand new cat for less than $50. The Magnaflow High Flow "direct fit" cat for my Honda was only $80. A universal weld-on cat (which is what one has to use in the Fiero anyway), is going to be $50 or less.
Originally posted by AL87: the old one rotted away, a replacement is not on my list. and my state isn't emissions controlled, so I think i'll save my money.
Every state in the Union is "emissions controlled," whether your locality has yearly inspections or not. The law is a Federal statute, not a state law. Also, I guarantee your state law, and probably local law, prohibits the removal of a cat or muffler, as part of noise control laws. Just because you don't have emissions or safety inspections, or because you can get antique plates, doesn't mean removal of the cat or muffler suddenly becomes legal.
And if you want to save money, take the bus. At least then you'll be saving money and doing some communal good in the process by helping public transit, which are constantly being upgraded around the country to run on cleaner fuels.
[This message has been edited by dobey (edited 03-10-2014).]
Holy crap, I didn't know Fiero owner where a bunch of tree hugging liberals. He asked if anyone has info on how is the best way to do the mod he wants, not on how you feel about global warming. So quit high jacking his post. If you want to talk about environment stuff then start your own thread that isn't in the "Tech Questions" forum. Just saying.
If you want to make insults or political statements, take it to a PM or TO/T where it belongs.
The "best way" to do what the OP wants is to install a new cat and muffler in the correct locations as per OEM. Installing a glasspack where the cat is, isn't going to make the car "quieter." It's just going to make it sound like crap. And the topic is "why not?" not "what is the best way to do it?" Pollution and noise control provided by the cat and muffler, are perfectly good "why nots."
My first Fiero came with a catalytic converter and no muffler. 85GT 4-speed. At first, the 'sound' of power was enjoyable, but after making a few road trips, the drone overpowered conversation and the radio and just didn't fit the car, in my opinion. I replaced the whole system when the converter clogged up. It had passed prior emissions tests, both at idle and at road speed tests with just a converter.
I have an 87GT with the converter removed from an otherwise original exhaust system. It has a little stronger note upon acceleration but really isn't noticeable at cruising speeds. I also have an 86SE with a full stock system. Very quiet under most all conditions.
I remember hearing a Fiero with just a glass pack for a converter, many years ago, and as I remember, the sound just didn't fit the image of the car. Location in the exhaust system does make a difference in sound.
[This message has been edited by fierofool (edited 03-10-2014).]
They wanted $600 for 2 converters with tail pipes and still needed the mufflers at $200. I cut them off after the converter and put in duals for $100. cheaper and sounded better than spending $1,000.
I wouldn't expect the glass in the glasspack to survive the heat of being that far upstream in the exhaust system. Might as well just use a resonator. Probably a bit cheaper.
OTOH, from the prices I've seen, glass packs are like $40, and a new generic cat can be had for like $70 or less. Its not that great of a savings, so I'd stick with the cat. If you've been seeing over $100, I could understand wanting to go with a more affordable glass pack.
25" Glass packs are at Advanved/ auto zone for $24 all day long, "Sound" better than a straight pipe, They Do Last. but are Not a Quiet as a Cat. " Loud and Rasp"y is Not cool (only to teens)." Fast and Sneaky" is cool.
I tried a straight pipe on my '86 GT, and it ran fine, but it was a bit noisy for me. I changed it to a resonator and that seemed to knock the growl down a bit and I'm happy with that solution. I ended up doing the same thing on my '88 GT as well.
I bought a brand new cat off eBay for my duke four years ago. Cost me a grand total of $20... which included shipping!
I acquired an '88 Formula last July which still had the original cat on it. Needless to say, the cat was not functional any longer. Picked up a brand new cat for the Formula off eBay for $33 (including shipping).
I don't want to hear that the "cost" of a cat keeps anyone from putting one on. That's just plain BS.
When it's so obvious from the stench that comes out of the exhaust tips that a cat is either missing or dead, I don't understand why anyone would argue against replacing it.
And a person's political persuasion should have nothing to do with their decision. We've all got to breathe the same air.
The only cars I remember stinking up the road was the first cars with cats. Smelled like burnt eggs. We used to put glass packs on all our cars in the 60s/70s. Then we would fill the tailpipe up with water. The glass packs were really filled with steelwool, not fiberglass. By a few days after being soaked, it was all crumbled and gone out the back. I dont have a problem with a cat on my car as long as its working right. But if it clogs up, its gone unless it has to be inspected, which its not here. I dont know where all these cheap cats are. Thieves cut them off and get $25+ for them as scrap.
To reduce noise you want to put the noise cancellation device of your choosing as close to the tailpipes as you can. This will avoid resonance from a long "straight pipe"
AL87 mentioned he was going to use a pretty aggressive camshaft. An engine with a lumpy camshaft usually needs to run a bit rich. Rich exhaust fumes will shorten the usable life of a catalyst significantly.
If you guys are so concerned about the environment, you should buy him a catalyst. Put your money where your mouth is.
To answer the original question, a glass-pack muffler may not last very long in the catalyst location. You'd be better off with a resonator or a chambered muffler.
I havent cut one up in years, but I never seen a glass pack with anything other than steelwool in it. Some they just call a glasspack when all it has is baffles along the inside walls.
Back on topic I would say it would be better than just having a straight pipe. You need something to there to create a little back pressure. There was a good thread on here that I read recently talking about the exhaust cycle and needing something within six feet of the y pipe to break it up. The muffler in stock location is just pass six feet. car will run better with something there.
now if you could find said thread, that would be great! I read that somewhere as well but I cant seem to find it with the search function.
My first Fiero came with a catalytic converter and no muffler. 85GT 4-speed. At first, the 'sound' of power was enjoyable, but after making a few road trips, the drone overpowered conversation and the radio and just didn't fit the car, in my opinion. I replaced the whole system when the converter clogged up. It had passed prior emissions tests, both at idle and at road speed tests with just a converter.
I have an 87GT with the converter removed from an otherwise original exhaust system. It has a little stronger note upon acceleration but really isn't noticeable at cruising speeds. I also have an 86SE with a full stock system. Very quiet under most all conditions.
I remember hearing a Fiero with just a glass pack for a converter, many years ago, and as I remember, the sound just didn't fit the image of the car. Location in the exhaust system does make a difference in sound.
I've had a few fieros in my shop recently and they are all pretty quiet from what mine was two were had cat deletes, one had a performance muffler and one a stock, and the last one had OE replacements, and that was TOO quiet. I just don't want that droning noise anymore. OR the loud noise at 4-5&6k rpm from WOT acceleration from a stop.
my own research elsewhere is leaning towards a cat causing a real tinny, ricey noise.
To reduce noise you want to put the noise cancellation device of your choosing as close to the tailpipes as you can. This will avoid resonance from a long "straight pipe"
that is the problem... there's almost no space, and stock routing is TIGHT. if I can find something to put in place directly behind the tips I would.
I think I'm going to have to find a performance muffler of some sort and fashion something in the oe location.
BLACKTREE: yes, I am. that cam is going to be at least a 290, I've already got a cam card from the manufacturer Im using and I've been stressing to them for the peak hp of the cam to be at 6k to make the most of the restrictive intake (which I'm going to modify later on; PPG style upper plenum, with a... dawg style neck) I gotta look into getting some equal length headers... not sure if i'll want long or short tubes though...
