muffler/exhaust for 5.3 trailblazer ext

[kadillackelley]

Hello all and great forum!! I just bought a 2005 trailblazer ext with the 5.3 and was wondering what muffler/exhaust you guys have had experience with?? I was thinking of either a flowmaster 70 series or a magnaflow-I want something that sounds good but doesn't have the interior resonance or droan. I was thinking of getting a single in/dual outlet muffler and running the tailpipes straight out the back. Any info would be greatly appreciated.

[Spong]

Big Ed did pretty much that exact setup on his EXT Envoy with the 5.3. I did a single in/dual out Flowmaster 70 on mine and it sounds great. I had a 50 series first and it sounded awesome around town but droned too much on the interstate.

[Viper12873]

This may have been the "hick rig" way to go... but I just cut out my stock muffler and put in a straight pipe... it's got a good tone... loud when you want it to be, quiet(ish) when you have your foot out of it. My only complaint is that it raps when you're under heavy acceleration and it switches gears. May upgrade to a flowmaster later on, but for now i'm content with my $15 exhaust system... lol:)

[kadillackelley]

How is the drone inside the cab with the 70 series flowmaster??

[Spong]

How is the drone inside the cab with the 70 series flowmaster??

Pretty much nothing. I don't even notice it because it's pretty quiet inside.

[big ed]

here you go. flowmaster 70 series. single inlet / dual outlet on a 5.3.

http://s54.photobucket.com/albums/g84/biged_2006/?action=view&current=CLIP0001.flv

quiet at highway speeds, no drone. about the only time it roars is when you step on it.

[Bounty_Hunter]

Sounds sweet, may go with the 70, but any problems with removing the resonators and the DOD on my 5.3?

[Spong]

Sounds sweet, may go with the 70, but any problems with removing the resonators and the DOD on my 5.3?


If yours is a 2005 then you don't have the DOD anyway. The DOD is really the #1 thing that makes good exhaust sound terrible. I'm going to have the DOD shut off on mine soon.

[Envoy Fan]

If yours is a 2005 then you don't have the DOD anyway. The DOD is really the #1 thing that makes good exhaust sound terrible. I'm going to have the DOD shut off on mine soon.

Well, if he has the XL, which it sounds like he does, then the '05 5.3L does have the DOD and is activated.

The '05 Short Wheel Base trucks with the 5.3L have the DOD parts, just not activated. The non-activation had something to do with resonance or noise problem when moving between 4 cyl and 8 cyl modes. They got the engineering issues fixed in the '06 models so all have DOD.

http://www.tbssowners.com/forums/images/smilies/boff.gif

[Bounty_Hunter]

Our '05 TB does have the DOD since it is the EXT. Am I able to install a performance muffler without the resonators?

[Scarsman]

How is the drone inside the cab with the 70 series flowmaster??

I have that on my suburban and it has no drone at all.

[Spong]

Well, if he has the XL, which it sounds like he does, then the '05 5.3L does have the DOD and is activated.

The '05 Short Wheel Base trucks with the 5.3L have the DOD parts, just not activated. The non-activation had something to do with resonance or noise problem when moving between 4 cyl and 8 cyl modes. They got the engineering issues fixed in the '06 models so all have DOD.

http://www.**********.com/forums/images/smilies/boff.gif


Really? :undecided I didn't know the EXT models had the DOD activated in 2005. I've seen older V8 EXT models and I noticed the factory exhaust doesn't have the resonator (which is how you can tell if it's a V8 or I6 form behind).

[nowgrn4]

Called muffler shop yesterday.Owner said he would do 70 series,single in dual out with 3" ss tips for $321 out the door.When I picked it up it was way to loud(I loved it but TB is my wifes daily driver).When I looked underneath I saw he had installed a series 40.I told him I wont pay until I get what I agreed to.He ordered 70 series in front of me and asked me to bring it back today to fix.Much better sound now !Low rumble at moderate throttle and a awesome growl WOT.Not too much,just right.I will use TB as tow vehicle.65 MPH in 3ed gear is 2750 RPM.I know I would get tired of 40 series after hours and hours at highway speeds.Just my opinion.

[Nukedog]

Called muffler shop yesterday.Owner said he would do 70 series,single in dual out with 3" ss tips for $321 out the door.When I picked it up it was way to loud(I loved it but TB is my wifes daily driver).When I looked underneath I saw he had installed a series 40.I told him I wont pay until I get what I agreed to.He ordered 70 series in front of me and asked me to bring it back today to fix.Much better sound now !Low rumble at moderate throttle and a awesome growl WOT.Not too much,just right.I will use TB as tow vehicle.65 MPH in 3ed gear is 2750 RPM.I know I would get tired of 40 series after hours and hours at highway speeds.Just my opinion.


I tow with my TB and i can assure you that you do not want to cruise at 65mph with a load UNLESS 8mpg is what you want. Try 60mph and 2200rpm for about 12mph and get the plug and play tranny cooler from PCMforless...

[nowgrn4]

Wow,do you have 5.3?How much weight are you pulling down here in the flat lands?3.42 or 3.73 gears?I have installed B@M cooler and finish B@M temp guage install this weekend.I'm hoping for 11to13 MPG pulling 3700-4100Lb TT W/Flowmaster,Airaid and PCMforless towing tune.

[nowgrn4]

Well we took TB out last night for a spin.70 series barely noticeable in cabin at highway speeds.When DOD switches on and off you can tell,it burbles on DOD.IT sounds like you let off the gas and are coasting down hill.Thanks.

[Nukedog]

Wow,do you have 5.3?How much weight are you pulling down here in the flat lands?3.42 or 3.73 gears?I have installed B@M cooler and finish B@M temp guage install this weekend.I'm hoping for 11to13 MPG pulling 3700-4100Lb TT W/Flowmaster,Airaid and PCMforless towing tune.


You being a smartass with your first line? I pull a 6x12 enclosed trailer with 2 motorcycles so it is about 3500lbs. PCMforless tune / K&N / 3.42 gears and 30.5" tires.

At 62mph pulling in "D" i get about 12mpg.

At 66mph pulling in "3" (since it will hunt for gears at that speed) i get about 10mpg.

Remember that weight is not the only factor. My trailer is high in the wind above my TB so it has alot of resistance. And remember that stop and go traffic kills gas mileage even more.