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5.3L DUALS

brsofla

brsofla

SM 2004
SM 2003
Full Member
Joined
Aug 1, 2003
Messages
728
Followed a lot of threads regarding the correct pipe sizing for the 5.3L Avi. Thinking of a single in, dual out muffler and was wondering what is the max tail pipe size that can be installed, regarding the back pressure issue?

Whatup? ???
 
I am running a single in dual out and they ran 2.25" pipes off of each dual out. The passenger side was fine but the drivers side is close.
I believe that 2.25" is the recommended pipe size to maintain back pressure to avoid any performance loss. I have 3.5" slash cut tips on each pipe behind each rear wheel.
Hope this helps
 
I just replaced the stock muffler with a flowmaster 40.......

Cheap...and sounds great......went with a one with 3 in and dual out to match up to the stock Y after muffler........

sounds great and no loss of power any where......

My buttometer needs calibrating so I cannot tell ya what I have for gains.......
 
;D Exactly what I needed to know ;D

Thanks so much for help.
 
Went with 3" in and dual 2.5 out the back. Butttometer says "making power" and sounding goooooooooood!
 
Welp,
Went to the old Mufflers R Us place and got a quote for a Flowmaster 40 with dual out, 2 1/4 inch duals with 14 inch chrome tips. All welded, etc. $350.00.

Is this about right or am I gettin' hosed? ???
 
Good price I have duel 40s coming straight out the back feels and sounds great
 
brsofla said:
Welp,
Went to the old Mufflers R Us place and got a quote for a Flowmaster 40 with dual out, 2 1/4 inch duals with 14 inch chrome tips. All welded, etc. $350.00.

Is this about right or am I gettin' hosed? ???
Click to expand...

'bout right ...

11H
 
brsofla said:
Welp,
Went to the old Mufflers R Us place and got a quote for a Flowmaster 40 with dual out, 2 1/4 inch duals with 14 inch chrome tips. All welded, etc. $350.00.

Is this about right or am I gettin' hosed? ???
Click to expand...
Just an FYI:
Have you been in a truck that is running a FM40 yet? Be forwarned that the interior resonance is pretty annoying to some folks and too others it is sweet music to their ears >:D
 
TNAV03 said:
Just an FYI:
Have you been in a truck that is running a FM40 yet? Be forwarned that the interior resonance is pretty annoying to some folks and too others it is sweet music to their ears >:D
Click to expand...

music to my ears...and no one has ever said it resonates or has complained.....even my dog likes it,,,,,,,hehehe
 
saw a WBH going down I95 south with duals. had the rectangular tips like the Z-28. sounded like the cab would have alot of resonance as it was kinda loud when it cruised by. it looked pretty good though.
 
I have the 40 series Flowmaster with 2.25 duals and 3in stainless tips out the side. Resonance isn't too bad. I really only notice it between 2000 and 2200 RPM.

I paid $275 for everything installed.

>:D It definitely gets a lot attention. >:D​
 
Savin' up the pennies, as we speak....Can't wait... >:D
 
go for the 70 series in stainless.
I have a 50 with 2 1/4 duals and it resonates at 60 MPH
sound is cool, resonance is tedious.
I paid $99 for the muffler in stainless
$165 for the install and pipes.

my humble opinion is that $350 is steep
 
Av "newbie". 40 Flowmaster, 2.5 duals. I assume this means single muffler, one pipe into muffler, dual pipes out each side behind rear wheels (same as stock only on both sides and w/ chrome tips).

Assume above is correct - where did you order the Flowmaster setup, who installed it (especially for $ 275)?

Thanks for all your help!
 
Haven't got it on yet. My $275 contact turned out to
be $325. I got a quote from Midas Muffler for $350.
Since the $325 guys are 25 miles away, I'm thinking of
the Midas offer. Check out a couple of posts above
yours. These dudes are spouting mid $200's. I'm
gonna contact them and see how they got the big
discount.

The price was for a Flowmaster 40 after the Cat,
Single input, dual outputs to twin pipes and 18 inch
chrome tips (round). I was thinking of leading them
straight out the back, instead of the side. Any
comments?

Thanks for asking.

Lee
 
Lee,

Re: out back vs. sides. In my opinion, it's personal preference. If I do something, I am going out the sides. I am somewhat concerned about other posts re: reduced backpressure causing loss of low end torque. I don't want to lose anything, just gain some sound and improved looks.

Thanks!
 
WHy DUALS? LOOKS or performance (which has not been proved wither way by anyone other than their buttometer....

I have not read where someone has dyno stock .,..then raplced exhaust and dyno again.....

what is the matter with single exhaust?

Curious is all
 
It may be no diff at all ???, duals vs single. Its a mod pref. for me ;). When I finally do it it will be duals out the back (probably) chrome flame engraved tips :cool:. I've always liked the duals and feel that to the average Joe on the street it represents performance. Not many high end performance vehicles use singles with anything V6 on up. Just MHO.
Theo (y)
 
This is my first post. :0: I didn't think I would ever have any knowledge that would amount to the vast experience located on this site.

Anyways, I am a muffler Tech, I have put 50 series Flowmaster on a few av's (encluding my own). Everyone has loved the sound. There is not much resonance inside. You can still hear the radio, cell, conversation. There is no constant vibration. The sound is more present apon startup and around 2k rpm. To install the flowmaster 50, I cut the Y pipe that is right behind the stock muffler and went with single out , with a tip. Preformance wise you should not have a problem if you stick with the 3" piping that comes with the AV. If you go duel you should stay with 2 1/4 or 2 1/2 size piping. I would reconment 2 1/2 IMHO.

Have fun
Ken (y) ;D >:D
 
Hey Guys,
I just installed a Gibson dual extreme cat back system on my 02 AV and love it. I believe the outlet pipes are 2.5-2.75" and the kit comes with 2 stainless steel 3.5" tips. The sound is nice and deep and doesn't bother you in the cab. It might be the placebo effect but it feels a little stronger in the 2000-3500 rpm range. Easy install if you whip out the cutting torch to get your old one off. Model 6300 @ $340 from 4 wheel drive parts. ;D
 
I went with the Single 3 inch in and Dual 2.25 inch out.

I have back pressure issues at around 50 MPH when I punch the throttle at that speed. However, I have more power at around 30 MPH than I did before this mod.
 
conacted gibson regarding duals on the 5.3, below is a copy of the e-mail I recived back.


Our single Swept Side. This kit is the ultimate power producing performance
exhaust for towing, off-road use and more pulling power. This is our best
performing system that we offer. This system will give you better low-end
then the dual will. Gives you a deep throaty sound at the tailpipe but still
quiet inside the cab. Follows O.E. routing and exits in stock location with
a large polished stainless exhaust tip.

DUAL SPORT TRUCK EXHAUST
Awesome super street look with maximum towing and pulling power. This system
is more made for a little more sound. Nice deep throaty sound at the
tailpipes. You will still see better performance but not as good as the
single. Follows O.E. routing and exits in stock location with twin pipes and
two large polished stainless exhaust tips.


 
KennyJoe2 - Some questions.

1. Where would you recommend buying the Flowmaster system from? What outlet/etc?

2. If I were to go w/ the system you recommend for single in, duals out - would I see any reduction in HP, torque, towing power? (want to tow 21 ft. Sea Ray that is on tandem trailer, weighs @ 4500 lbs.)

3. What should I expect to pay for this system?

Thanks for your help....

 
To answere your questions tafirehawk309, if you went with the duels out the back or to the side you would not have any loss of preformance, so long as you keep the pipe size down to at least 2 1/2. If you go with 3 in. out the back you will see a loss of power. Expecialy while towing due to no back pressure.

As far as recomending where to go. I can not say, I would recommend talking to a preformance speed shop. I'm a little partial to flowmaster, plus I build exaust systems (so no pre-fab systems, only custom).

IMHO :0: ??? :0:

L8ter,
Ken
 
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