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Discussion Starter #1
Now this truck sounds like it has 400HP and backs up the SS badges :yes: :D . My performance oriented personality got the best of me today as I just couldn't stand how quiet the stock exhaust was , so I went to Mufflex custom exhaust shop in Trenton , NJ to see what was worth changing on the stock system , first they took off the stock muffler and checked it out , and while it is straight through , it does have a bend in it at the end , and the baffling and sound absosrbing material is probably hurting flow a little bit , I did this mostly for a more performance sound than for horsepower , so they put a Magnaflow on it and I took it for a test ride on the highway , the truck was still too quiet , barely louder than stock , so back it went on the lift and off came the stock resonator , when I first started the truck with the resonator off , I knew right away it was the sound I wanted , it's not too loud on the highway or at cruising speeds , but when you get on it , it sounds awesome , I think I could best describe it as loud enough to turn heads , but not too loud , and not even close to obnoxiously loud , in fact at cruising speeds its quieter than my old 5.3 Yukon that had a magnaflow and dual tailpipes . Performance wise it does feel more reponsive and a bit quicker , it is definitely breathing better than the stock system .

I plan to run the truck next weekend on opening day at Raceway Park , Englishtown in NJ , so if any of you local guys will be there you can check out the sound for yourself . By the way , Mufflex had a brand new red Jeep STR-8 in the shop yesterday getting new mufflers and the resonators deleted so those Jeep guys aren't just going to sit back and leave those beasts stock either , maybe he'll show up at the track next weekend and we'll have some fun .:D
 

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yah 5x8 or 4x9 case

14case /20 overall length
orrrr
18case /24 overall length

im doing a 3 inch mandrel bent set up. Thing is im wondering if the magnaflows will drone in the truck.
 

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im wondering if anyone has just cut off the resonator on the stock set up. I dont pick my tbss up till thursday but the stock sounding exhaust sounds way to quiet.
 

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Discussion Starter #6
TBSS said:
Would love to see pics of the inside of that resonator as well....please! :D
The stock resonator is also a straight through design , it probably doesn't rob any horsepower , it just does a good job of killing the sound .
 

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Discussion Starter #7
NORCAL SS said:
im wondering if anyone has just cut off the resonator on the stock set up. I dont pick my tbss up till thursday but the stock sounding exhaust sounds way to quiet.
I would reccomend trying that first to see how it sounds , it might sound perfect for you , everyone has a different preference .
 

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Discussion Starter #8
NORCAL SS said:
yah 5x8 or 4x9 case

14case /20 overall length
orrrr
18case /24 overall length

im doing a 3 inch mandrel bent set up. Thing is im wondering if the magnaflows will drone in the truck.
There is no drone sound , however , with the slightest touch of the gas you hear the exhaust . I'm not sure which Magnaflow it was , it is still a big muffler , only an inch or two shorter than the stock one . I'll try to find out Monday or you can call Mufflex if you want . www.mufflex-performance.com
 

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Any chance you can give us more specifics of the stock exhaust? Like the ID or OD of the stock piping? Did you replace any of it? How about that flattened piece of piping over the axle?
 

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Discussion Starter #11
Zerumm said:
I'm sorry for being abit slow but, basically you took the resonator off and put the mufflex on? :(
I replaced the stock muffler with a Magnaflow , and cut off the stock resonator .
 

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Discussion Starter #12
TBSS said:
Any chance you can give us more specifics of the stock exhaust? Like the ID or OD of the stock piping? Did you replace any of it? How about that flattened piece of piping over the axle?
The stock piping changes from 2-3/4 at the inlet of the muffler to three inch coming out , I didn't want to mess with the over the axle pipe , because of clearance issues and we didn't have time today , overall I think there is minimal power to be gained with replacing the muffler/tubing , maybe 5-10hp , like I said I went more for the sound aspect , although if you put headers on the truck , the rest of the system might be more critical , I'll see what kind of gains the headers make , and then I'll cross that bridge .
 

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so wait from the muffler back its a true 3 inch set up. It doesnt taper down to 2 3/4 going over the rear axle.

your saying the muffler is 2 inhes shorter than stock?? the next size for the magnaflow is 24 case length and 30 overall length so i think thats what you used.

now there is no drone you said im wondering if i went with a shorter muffler which im planning to do wonder how much louder it will be. Is the stock tbss exhaust stainless steel or aluminum

thanks man

tony
 

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Discussion Starter #14
NORCAL SS said:
so wait from the muffler back its a true 3 inch set up. It doesnt taper down to 2 3/4 going over the rear axle.

your saying the muffler is 2 inhes shorter than stock?? the next size for the magnaflow is 24 case length and 30 overall length so i think thats what you used.

now there is no drone you said im wondering if i went with a shorter muffler which im planning to do wonder how much louder it will be. Is the stock tbss exhaust stainless steel or aluminum

thanks man

tony
The stock exhaust is stainless , the system is 3-inch out of the muffler then it does kink down over the axle and then goes back out to 3-inch , but the guys at the shop do alot of f-bodies with their kinked up y-pipes and they never saw a gain in times at the track from replacing the kinked up y-pipe on those cars so they didn't feel it was worth replacing the over axle pipe , it's hard to say if it would make a difference , if it was a 700+rwhp car then yes , I would definitely have mandrel bent all the way through .
 

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yah i got a email back from the shop. they said theyu used a 5x8 muffler in your truck just trying to figure out what length. also they said they used "a custom resonator eliminator " which im guessing is just cutting off the resonator and adding 3 inch pipe in its place.

now you can hear the exhaust but it is a little loud at all when you romp on it or is it fairly quiet still

thanks
 

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e bay muffler is 84 shipped
and to have a shop cut off the resonator and put a pipe in and weld the muffler in out here is 30 bucks.

im saying at most 120 bucks and that includes the muffler
 

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I Do think the trailblazer ss has a offset entry/center exit muffler. the 4x9 case will be much louder thats why a 5x8 case is better to go with.

here is the one im planning to install (5x8 case)
20 inch overall length 3 inch offset entry/center exit
http://cgi.ebay.com/ebaymotors/3-O-C-5x8-Oval-18-Body-MagnaFlow-Muffler-SS-12259_W0QQcmdZViewItemQQcategoryZ33636QQitemZ8035467191QQrdZ1


the one that is 2 inches smaller than the stock one is this one (5x8 case also)
30 inches overall 3 inch offset entry/center exit 3 inches
http://cgi.ebay.com/ebaymotors/3-O-C-5x8-Oval-24-Body-MagnaFlow-Muffler-SS-12289_W0QQcmdZViewItemQQcategoryZ33636QQitemZ8035467212QQrdZ1QQsspagenameZWDVW
 

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STEALTH SS said:
The stock piping changes from 2-3/4 at the inlet of the muffler to three inch coming out , I didn't want to mess with the over the axle pipe , because of clearance issues and we didn't have time today , overall I think there is minimal power to be gained with replacing the muffler/tubing , maybe 5-10hp , like I said I went more for the sound aspect , although if you put headers on the truck , the rest of the system might be more critical , I'll see what kind of gains the headers make , and then I'll cross that bridge .
a couple of us were already planning to go to Eng.Town this weekend (waiting since last month when they released their 06' schedule!) so I am sure we'll see you there, sounds like you're waisting no time seeking out another 9sec vehicle??:eek: .... I bet this is how the vette started out isn't it??

I am curious about one thing.. you say the stock muffler was straight through and only had some baffling inside, also the resonator, yet you claim a HP advantage? I personally will not do the exhaust until headers/highflow cats, Etc. have been fitted. (I understand you wanted a better sound) I just don't think you would gain even 5HP from what was done, which is why I am waiting for the whole exhaust... Truck has a hi-flow (for factory, anyway) muffler/resonator and 2.75" pipe into 3" already..so would you say this a sound only mod, or do you believe there really is a 5-10hp gain? these engines seemed to be more restricted up front (manifolds), at least the claimed/confirmed (dyno's I've seen posted on the other sites, albeit GTO/Vette LS2's) HP gains from a header install would lead you to believe that, so how much more freely would /could it flow if the exhaust isn't getting out of its own way to begin with? don't mean to be skeptical, just in my nature, when the majority says otherwise..
 
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