I'm new to this tuning stuff so I'm I'm trying to set up badmad header, zzp 2.5" dp, 2.5" cat-back. On zzp website there are bunch of options so for dp i was told to get high flow cat and I'm not sure what to pick for cat-back. It says no downpipe flange (weld-in), Bolts up to 2.5" downpipe flange, and Bolts up to 3.0" downpipe flange. So which one do i need for my zzp cat-back?

 

I would get the 3 inch downpipe with a 2.5 inch exit. Then get the 2.5 inch bolt on cat back.

 

depends on your power goals. letting us know what car you have would help as well, even though im guessing lsj.
up to around 255whp your good with 2.5" anything after that most tuners would recommend 3" all the way.

 

I would say that you'd be looking for the downpipe with the 2.5" flange. You just need to make sure that the DP flange matches the catback flange. If you already have the cat-back, you need at dp with the 2.5" flange. If you already have the dp, make sure that the flange is 2.5" which it should be because it is a 2.5" dp.

Hope this helps.

 

I got 06 SC/SS, so 2.5" dp high flow cat and cat-back w/ Bolts up to 2.5" downpipe flange?

 

But isn't the BadMad header 3"? So should i be getting 3" dp?