I just ordered a Dynomax Super Turbo muffler. I want to have an exhaust shop build me a catback, but none of the places have mandrel bent pipes. Do I want to go 2.75 non-mandrel from the cat to the muffler (keep in mind the muffler has only a 2.5 inch inlet) or just go 2.5 non-mandrel?

Being that the stock piping is 2.25 mandrel, is 2.5 non-mandrel is even an improvement?

2002 3.8 Camaro M5 Navy Blue Metallic
Y87, Sport Appearance, T-Tops
SLP CAI, K&N, Whisper Lid, Pro 5.0
Kenwood KDC-MP919, Kicker IX405D, Focal Polykevlar 165K2s, JL Audio 10w3-2 Stealthbox

 

I would at least go 2.75" or 3".If you can,find a used exhaust from a WS6 or SS.They came mandrel bent and will fit right up to your car with a hanger and reducer.Good luck.
Kevin

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1998 Black Z28 A4
-------1/8-------
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2.5 non-mandrel Naw,you are getting the same(maybe a tiny less than) flow now Stock.
The 2.75 non-mandrel Yeah little bit more than 2.5 mandrel.A little more available volume further back.Since the non-mandrel on the 2.75 will get down to almost 2.5.
3" non-madrel into a 2.5 inlet could cause some unsavory vortex'defeating smooth flow.
I assume you got dual outlet?
But I do agree w/ Kevin,thats the best way,if you can get it.
Also Huskers High Performance has alot of Exhaust parts incluing the reducers you asked about.
T.

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Hella Clean Dark Green Metallic 98 3.8 L60E Coupe:Fast toys Ram Air,Holly filter,Whisper lid,160 Thermo,Man.fan switch,Purple ice wetter,Eibach Pros,Koni adjustables,BMR sways,Prothane bushins,Transgo kit,Magnaflow cat-back.National Auto Sport ***. member/student.

 

BigED,

I took my muffler to Midas and they mandrel bent me some pipes right there in the shop. It was cheap too! Just thought I'd toss it up. John.