Flowmaster Muffler

[DMNSMITH2]

I am wondering if I put a Flowmaster on my 2001 Z71 5.3L if it will lose any of its performance?  Has anyone out there done this?  What about warranty considerations.  I just love a nice sounding truck.  Thanks in advance for all comments.

[gmcjoe]

No problems with warranty.

Freeing up the exhaust on these 99+ Vortec engines has shown a slight loss of low-end torque. I have a single Flowmaster 40 (not delta series) single in/dual out muffler on my '00 Sierra. I love the sound and performance.

Check out th LS1.com truck forum for much more info regarding exhaust options on these new trucks.  A lot of people are happy with the setup available from http://www.pvmufflers.com/ Check it out.

[y2kz71]

Hey gmcjoe, what size inlet and outlet are you running? Also where do the pipes exit? I just got my 2002 flowmaster catalog in the mail and I am fixing to run a similar setup. How is the interior resonance? I am kinda leaning toward the delta flow 40 series but I don't know.

Thanks

[gmcjoe]

My tailpipes exit along side the spare tire and dump down. I kept the factory diameter (whatever that is).

The Delta flow is quieter than the regular 40 series.

The resonance isn't bad at all.

[burgundyz71]

I was looking at the pvmuffler site gmcjoe linked and seems they are the only ones to claim torque increase and the way people say they loose torque with flowmaster this may be the way to go. Anyone know anymore about these

[EDZ Z71]

I am running Flowmaster 70 series because I wanted quiet. It did hurt the low end torque in my opinion though. But I will make it up later. I have a 3 inch inlet and dual 2 1/2 outlets.  Sounds nice and mellow. At 70 on the interstate you can hear it. With my db meter it reads approx. 75 db, a weighted and slow response. You can have a normal conversation. When you get on it from a stop they do sound off.