So I got my zzp downpipe today with cat and 3inch bolt in. Why is the exit 2.5 inch and will that connect to the hahn exhaust?

 

the exit is a 2.5 cuz its ment to hook up to the stock or aftermarket exhaust with that same diameter. Not sure what size the hahn is, so i cant answer that.

 

Since you have the Hahn you should have purchased the ZZP 3" Downpipe w/ 3" bolt in exit.

I know Hahn sells a reducer for their catback so you can bolt it up to the stock downpipe, or 2.5" exit aftermarket downpipe. If you dont already have one either pick one up from Hahn, or return the downpipe for one with the 3" bolt in exit.

 

I did order the 3" bolt in, there wasnt an option to select the exit size. So I read the hahn exhaust page and it sounds like it bolts up to stock size exhaust until you take out the reducer and it can work with a 2.75 or 3" So hoping that means it will work with a 2.5" with the reducer on

 

Yes, there is an option for the exit size. Please look at ZZP's page again (under Option 1). They give 3 options (2.5" bolt in, 3" bolt in, & 3" weld in).

Cobalt & Ion ---> ZZ Performance

With the reducer on it will work with a 2.5" catback.

 

I know that option and I selected 3" bolt in like I stated and payed the 20 bucks. as long as it will connect to a 2.5" like you said then I guess it will be alrite

 

Dude, re-read your first post. You are asking why the exit is 2.5". That to me sounds like you were talking about the downpipe. Did you mean why is the inlet of the Hahn 2.5"? In that case remove the reducer. The reducer is so you can install the Hahn catback to the stock downpipe, or a downpipe with a 2.5" exit.

^See

 

The downpipe I got from zzp that I orderd was a 3'' (with the option 1 selected as 3" bolt in for extra $20) When I got it today I saw that the inlet was 3" but the outlet was 2.5" So since I saw the exit was 2.5" I asked if that would connect to the hahn exhaust. You said yes it will as long as I leave the reducer on.

 

if u got 3" it should be 3" inlet/outlet, no?

 

it should be, mine looks exactly like the pic of the downpipe with the cat Cobalt & Ion ---> ZZ Performance

 

No.

There are three options for the ZZP 3" downpipes.

2.5" bolt in, 3" bolt in, and 3" weld in. These are all pertaining to the exit portion of the downpipe.

- The 2.5" bolt in is for use with the stock catback, GMPP catback, or aftermarket 2.5" catback.

- The 3" bolt in is for use with a 3" catback.

- The 3" weld in is for use with a custom 3" catback.

Ok. Now you made yourself more clear. Yes, if you keep the reducer on your Hahn catback you will be able to use the downpipe for sure. I would have been able to answer this quicker if you said ZZP sent me the wrong downpipe, haha.

 

wow what a confusing bunch of posts, did it end up bolting up? Just wondering bc the 3in bolt in exit on the zzp downpipe will not bolt up to the 3in inlet on the hahn catback

 

Yes it was. The first post in the thread was not 100% clear. If the OP stated that ZZP sent him the wrong downpipe in the first place this would have been solved a lot sooner, haha.

Since the OP has the ZZP 3" downpipe w/ 2.5" bolt in exit he will be able to install it to his Hahn catback w/o any issues.

 

Hmmm so I wonder why the 2.5 exit will bolt up with the reducer in, but the 3in exit wont bolt up to the 3in inlet?

 

Does the Hahn catback also come with a 3" 2-bolt flange that you can use instead of the 2.5" reducer flange? If so, I can't see why it wouldn't work with a 3" bolt in exit downpipe. Unless the flange widths are different sizes.

 

Well, it either comes with a 2.5 reducer, or a 3in, whichever you choose, so I chose the 2.5 to bolt up to my stock catback, which fit perfectly fine. Then when/if you want to upgrade, you get to drop 80 bucks on the 3in inlet to swap in haha. And yeah the 3in flange from hahn is a 2 bolt but you guessed it the zzp flange on my new dp is way wider, they dont even come close to matching up. So, I plan on just drilling my own holes to fit.