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Dual Exhaust for 8.1L

BooTheRedneck

BooTheRedneck

SM 2003
Full Member
Joined
Apr 29, 2002
Messages
459
Location
Birmingham, Alabama
I just had dual exhaust put on my 02' 2500 and so far so good.

I already had a dual 3" in - dual 3" out Magnaflow muffler and was utilizing the factory "Y" downstream of the muffler to have one tailpipe out the passenger side.

With the new setup, I got rid of the "Y" and ran (2) 2-1/2" pipes out the back of the muffler, one to the driver's side and one to the passenger's side. We went with 2-1/2" pipes so I would have the needed clearance around the rear end and the spare tire.

It doesn't appear that I will have any clearance problems (knock on wood.)

IMO, it sure sounds better. Insofar as performance, I didn't notice any difference, except that my torque curve may have slid up the rpm scale a bit, but I stay at higher rpms anyway! >:D

Boo.
 
BooTheRedneck, sounds good abd somewhat expected...

Personally I would of gone with 2.5 in the front and 2 1/4 out though.

Performance would be felt, aswel as your torque.

Glad you are happy with it.

Mine finally goes in on Thursday, for a complete change over with TOG's.


G. :cool:
 
Used Flowmaster on mine and ran my tips straight out.
Shay :B:

shay11.jpg
 

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I went to 2 different shops to get estimates for duals and both had the same response. "The system is a tuned system and if you change it, it will trigger the check engine light." Has anyone that has made changes to their 8.1 exhaust had and problems?

E.
 
luv2boat said:
I went to 2 different shops to get estimates for duals and both had the same response. "The system is a tuned system and if you change it, it will trigger the check engine light." Has anyone that has made changes to their 8.1 exhaust had and problems?

E.
Click to expand...
Nonsense - as long as you leave the cats and sensors in place you are fine - I suggest you find a small specialty shop - they will do you a better job and you can kibitz ;D
 
Actually, since there are NO sencors anywhere close to the cats... YOU CAN EVEN GET RID OF THEM IF YOU CHOSE TO and the lights still would NOT come on!!! Already tested that.

Wed. back in the shop to test another set up.

Here a pic's of the tips

G. :cool:
 

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Based on numerous postings I've read over the past few months, I recently ordered the Flowmaster 70 series big block muffler (PN530722) for my 2002 AV 2500. This muffler has a single 3" in and dual 2 1/4 inch out. While waiting for this muffler to arrive, I've read more postings and think I may have screwed up and ordered the muffler that "muffman" recommended for the 5.3. To install this muffler on the 8.1, an exhaust shop would have to build a Y into the muffler; not sure if this would create problems.

Has anyone tried the 530722 on the 8.1? I'm guessing I should send the muffler back and go back to the drawing board. Suggestions?

Thanks.

Kevin.
 
I have the Flowmaster 40 series on my 2500. I do not know the part number. Sounds like you ordered the 5.3 muffler. I have both pipes coming out the passenger side rear tire. To run one of the pipes to the driver side would have made a longer run, I wanted the pipes to be equal in length.
 
knowlesk said:
This muffler has a single 3" in and dual 2 1/4 inch out.
Thanks.

Kevin.
Click to expand...

Read my post back a few. I went w/ the Flowmaster 70 which sounds fantastic on my bigblock! Mine is the one w/ dual ins, dual outs. I ran the dual outs out at the original location. If you ordered the single in, that won't work without a y pipe. Beacause you already have dual exhaust running to your muffler. I am sorry, don't know the part # but hope this helps.
 
Oviedo,

I'm going to try the flowmaster 70 series dual in/out (P/N 524704) - - I believe this is what you have. Was there any problem with the inlet pipe size? Both in and out on this muffler is 2.25". I also want to run pipes out each side of the truck behind the rear wheels. Did you consider that?

Thanks.
 
Knowlesk,

Send that muffler back!!! It is for the 5.3L, and you don't want to choke down your exhaust by building a "Y" off your factory 2 3/4-inch exhaust pipes!
 
Muffman,

Already sent the muffler for the 5.3 back --- thanks. Any thoughts on the 70 series FM dual in/out? Seems a few people have used this and like the results. The exhaust shop I'm working with wants to run the drivers side exhaust pipe out behind the differential.

Appreciate your opinion and reply.

Kevin.
 
Knowlesk,

Out behind the diff? You mean over the pass side, then crossover down real low to go over to the drivers side? Like some kits? No, don't let them do it. With 2 1/4-inch pipe, any competent bender can go up and over the rear end and out to the drivers side. If the person who is quoting you doesn't feel comfortable doing this, take is somewhere else, this guy can't bend his way out of a paper bag! :eek:

As far as the Flomaster dual in out 70? Many like this choice. Just remember to use the equalizer pipe in front of the muffler, and keep the tailpipes no larger than 2 1/4-inch.
 
Muffman,

Thanks for the response and the reminder about the crossover pipe. The shop I was talking to stated they would not run the 2nd pipe over the differential due to safety concerns. I'll search for a shop capable of running the drivers side pipe over the diff and out the side.


Knowlesk.
 
muffman said:
Knowlesk,


As far as the Flomaster dual in out 70? Many like this choice. Just remember to use the equalizer pipe in front of the muffler, and keep the tailpipes no larger than 2 1/4-inch.
Click to expand...

Muffman, what is the reasoning behind this. I have that setup, but no equalizer pipe. I am sure there are benfits, but is it worth taking it back and having it put back?? Thanks Muff
 
Yes, by equalizing the exhaust pressure, it cuts down the resonation, and creates more efficient extraction through equalization of the exhaust. It is a must on the big block.

I could elaborate, but it is a pretty dry subject for most.... ;D
 
I finally had the flowmaster muffler installed with the pipes out behind each wheel; the shop I went to did a nice job. The only thing they could not do was install the crossover pipe. There is not enough room to install one on the 2500 due to the close proximity of one of the catalytic converters to the muffler. The sound is just what I wanted, not too loud, but still loud enough to let everyone know you're not driving a 4 cylinder truck.
 
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