3" downpipe to 2.5" catback
 

Generally speaking will a 3" downpipe bolt to a aftermarket 2.5" catback? Or is this something that will mostly depend on brand.

I don't think it depends on the brand.. I'm pretty sure you should be goor

thats my setup basically. ZZP longtubes 3in dp to a 2.5 mandrel bent back end.


I had zzp just weld a slip reducer to 2.5, and had the opposite end expanded to a ID of 3in and slipped it on and clamped it, and thats all there was to it.

They should bolt up but you might have issues with it leaking if the outlet of the downpipe isn't sized for the 2.5" inlet of the catback.

Do you mean a 3" through-out? That physically isn't possible. You will have to make some sort of flange to make it work. You can get a 3" DP that goes from a 3"-2.5" flange. That will work.

I hope I understood what you were trying to ask and answered your question.

YES it will work, if the aftermarket cat-back bolts up to your existing stock 2.5" downpipe it'll fit.. order a downpipe from ZZP. I got my ZZp catted 3inch DP with a 2.5" exit flange welded onto it and a extra O2 bung and plug for when i get a wide band! i got mine on black friday and saved 30% tho :lol: Mine being paired up with a magnaflow 2.5" cat back system

They give you lots of options, 3 inch exhuast exit or 2.5inch bolt on, extra 02 bung for wideband or not, gaskets, catted or not catted. and i believe they use magnaflow catalytic convertors

ZZPerformance - 3 inch Stainless Cobalt/Ion Downpipe #

:twothumbs

yeah it will work, mine was like that for a little bit. it leaked more often though

I had mocked mine up and didn't like the gap it had. I didn't mean to misinform anyone if it does actually work without leaking.

As stated... it will probably bolt up just fine but you will probably have to live with leaks. Why not get a DP with a 2.5" outlet?

or chop off the flange and weld in a reducer. thats what i ended up doing

i got long tube heads and gutted cat downpipe from vibrant that i hooked up to what i believe is stock 2.5 inch straigh catback... no gapping.. idk if that helps... prob not huh?