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Questions about my Thrush Glasspack....

Old 02-15-2011, 06:59 PM
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Questions about my Thrush Glasspack....

first, i love this site, its seriously taught me so many things about thirdgens and cars in general

ive spent hours reading about the war on glasspacks, for and against. and i decided that it's what i want, Im not here to argue about them. i just have a question.

I just ordered a thrush glasspack from summit, i got the 2.5 inch one. but the only one they had was 28 inches long. and i forgot to measure under my car before i ordered it

so am i gonna have any issues fitting this in the stock muffler location?
i think the stock muffler is around 21 inches long?
ive seen a few pics and videos on here with glasspacks, but nothing that really helps, i think i read one post about someone having to cut 4 inches out?

so anyone..!!
Old 02-15-2011, 07:12 PM
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Re: Questions about my Thrush Glasspack....

It will fit in the stock location.

Had mine that way before but I also shot the exhaust straight out the side.
Old 02-15-2011, 09:35 PM
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Re: Questions about my Thrush Glasspack....

sweet!! alright well question answered

i was also thinking about doing a straight shot out the side, do you have any pics of what that looks like??
Old 02-15-2011, 09:39 PM
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Re: Questions about my Thrush Glasspack....

also, would i be able to have my pipe facing the rear?? or would it look funny since the glasspack extends so far?
Old 02-15-2011, 10:08 PM
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Re: Questions about my Thrush Glasspack....

Ive had it lots of ways on my car.

Use to be like it was on the left in the pic, like what your talkin about.
All stock config but the glass pack shootin out the side for a straight shot.

I then changed it to like on the right, I cut the Y pipe end off [which is double walled] so it pointed straight down the side, not towards the center.
I was then able to tuck the pack right into that valley between the floor pan and sides. And then made it jet out the side cutting down the tip for a side pipe. [which only half worked, totally killed my higher RPM band, so I had to knock a hole in the end of the pipe so it could blow straight out too.]


Ive since then got sick of all the noise, cut off the tips sticking out the side, and ran the pipe straight out the back center so the folks behind me can listen too it




[IGNORE THE CRAPPY DOOR, BEEN REPLACED]

Last edited by Gumby; 02-15-2011 at 10:12 PM.
Old 02-15-2011, 10:59 PM
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Re: Questions about my Thrush Glasspack....

thanks for diagram, its really helpfull

did you have to delete your cat when you ran them out the side, stupid california smog bullshit keeps me from going crazy. they look so sick btw, really kick ***.

do you remember if you wouldve had space to make them face the rear when you had ur pack in the stock location? or is my best best a straight shot out the side??

well the people behind you deserve a little consolation, they are behind a thirdgen afterall
Old 02-15-2011, 11:30 PM
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Re: Questions about my Thrush Glasspack....

Originally Posted by 5speed88
thanks for diagram, its really helpfull

did you have to delete your cat when you ran them out the side, stupid california smog bullshit keeps me from going crazy. they look so sick btw, really kick ***.

do you remember if you wouldve had space to make them face the rear when you had ur pack in the stock location? or is my best best a straight shot out the side??

well the people behind you deserve a little consolation, they are behind a thirdgen afterall
no pollution police here = no cat

but there would of been room for a bullet cat too.

There is kinda enough room to run it straight but gonnahafta mod the stock config pipe I bet without having to add bends ya don't want. straighter the flow the better.
Old 02-16-2011, 11:32 AM
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Re: Questions about my Thrush Glasspack....

Originally Posted by Gumby
no pollution police here = no cat

but there would of been room for a bullet cat too.

There is kinda enough room to run it straight but gonnahafta mod the stock config pipe I bet without having to add bends ya don't want. straighter the flow the better.

alright, well it comes in today, ima go underneath and look at how things look with it there, and hopefully i can post some pics soon.

thanks for all the help man
Old 02-21-2011, 07:51 PM
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Re: Questions about my Thrush Glasspack....

just got my glasspack installed today, was a little dissappointed cuz it was so quiet, but driving it home it started to open up, and by the time i got home it sounded nice and throaty.

will post pics soon.

one thing tho, when i rev it to about 2000-2500 rpm i start hearing a faint whistling sound coming out of my muffler. my friend thinks because it perforated holes and the exhaust passing through makes whistles. any one have any idea what the sound might be? a bad weld maybe? a hole?
Old 02-21-2011, 09:01 PM
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Re: Questions about my Thrush Glasspack....

I never had that whistle on any of the 3 Thrush mufflers I've had, but then I've had exhaust leaks elsewhere with the ones on the Bird (the 24207, a 2" muffler, was on my Grand Prix and is now in my garage, sold that car). One thing I will say about these is that the paint or whatever is on the outside is really crappy. It will start flaking off in no time if you drive the car even in rain.

If you are after a different length, the Thrush website has varying lengths and their associated part numbers. I've generally run the 24201 (2.25" in/out and I've forgotten the length), but there is a 24200 available and up to, I think, a 24205 for those. I run the 24201 because its shorter length basically allows for a stock-like setup with the tail pipe on the driver's side.
Old 02-21-2011, 11:22 PM
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Re: Questions about my Thrush Glasspack....

dammit, i guess i have to take a closer look at the welds then. they looks pretty solid tho.

i read about people burning out the fiberglass inside, once thats gone wouldnt it be like having no muffler at all?
Old 02-22-2011, 01:16 AM
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Re: Questions about my Thrush Glasspack....

a whistle must be something else. now if you fully weld it on, I had ping n popin problems on cool down.

Like a hot motor on a summer days, but it was the glass pack, made a racket when stopped, fixed it by going for several long drives then quickly hosing down the muffler inside and out with cold water to shock it.

I no longer fully weld them

I use 100% clear silicone on the joint then just a tack weld here n there.

silicone wont burn out or leak, n tacks are easily un-done if need be.
Old 02-22-2011, 01:17 AM
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Re: Questions about my Thrush Glasspack....

Had mine on for 4 years (replaced it due to other problems and rust) with mostly running rich... Never burned out the fiberglass. However, there may be problems with power adders and such that increase exhaust heat (and excessive idling).
Old 02-22-2011, 01:59 PM
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Re: Questions about my Thrush Glasspack....

Originally Posted by Gumby
a whistle must be something else. now if you fully weld it on, I had ping n popin problems on cool down.
cud it be be a leak somewhere else in my system??
& yea i had it fully welded, a pretty gnarley looking weld actually, is that what caused ur pings? cuz u said after u stuck a hose in there it stopped?
Old 02-22-2011, 02:12 PM
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Re: Questions about my Thrush Glasspack....

Originally Posted by 5speed88
cud it be be a leak somewhere else in my system??
& yea i had it fully welded, a pretty gnarley looking weld actually, is that what caused ur pings? cuz u said after u stuck a hose in there it stopped?
I had bad ping and poping noises when hot, bad, folks would look at the car like it was a ticking bomb.

What I did was for several days, go on long drives to get it hot then come home and quickly hose the exhaust down, inside and out to flash stress the metal, it cured the noise after several times.

A whistle could be a leak in a weld, just the right size to make noise.

[How a whistle works, the right sized tiny hole and blow.]
Old 02-23-2011, 01:18 PM
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Re: Questions about my Thrush Glasspack....

http://www.youtube.com/watch?v=QMmNb98tiSk

an extremely quick video i made after waking up.

sorry about the camera being sideways, i was rushing.

so thats the faint whistling sound im hearing, its not all the time, but when i step on it, its clear as day.

i know people wont agree with this, but i put muffler cement on the welds, and made it look as clean as i cud. but that didnt stop the noise.

Last edited by 5speed88; 02-23-2011 at 01:19 PM. Reason: wrong link
Old 02-23-2011, 01:52 PM
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Re: Questions about my Thrush Glasspack....

I dunno, I only heard it faintly towards the very end.

Maybe its your turn out, I only run straight system, no turns cept real lazy easy ones and no axle loops, straight as I can get it.
Old 02-23-2011, 01:58 PM
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Re: Questions about my Thrush Glasspack....

Originally Posted by Maverick H1L
One thing I will say about these is that the paint or whatever is on the outside is really crappy.
Tip on that, repaint the muffler as needed but do it when its still hot.
The heat makes an instant cure and stick better then cold spraying.

I paint my exhaust black and just use regular 99cent cheap walmart spray paint, only the Y pipe gets to hot for it. Once a year I spend $1 n hose it all down when hot. [I like it blacked out.]
Old 02-23-2011, 01:59 PM
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Re: Questions about my Thrush Glasspack....

hmmm. maybe it is. well thanks for all the input man. youve been a huge help with all of this.
im hellbent on finding that whistle now tho.
a friend of mine driving behind me said that when i mashed it, it sounded like a blow off valve
Old 02-23-2011, 02:04 PM
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Re: Questions about my Thrush Glasspack....

that sounds like a actually. i believe im run to the store and pick up some paint
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