so down pipes what should I get 2.5 or 3 either one is catless so who has each and pros and cons.


whats the stock dp.

does the 3 in really drone?
i dont want to have to upgrade it later

 

What do you plan on doing down the road? 2.5'' is fine if you stay on the stock blower.

 

Yeah. IIRC stock is 2.5 but has nasty spots that dip down to 2.25.

 

^This

Don't bother with the 3" unless you have big plans for the future.

 

I was planning tvs next tax season.

 

he is talking about a downpipe not a cat back. do a 3 inch downpipe with a 2.5 exit. stock size is like 2.75 or close to that.

 

This

 

what does the resonator pinch down to ?
does anyone have a viable replacement for the resonator that not
huge?

 

3" downpipe for the LSJ. 2.5" downpipe would be smaller than the stock downpipe which is approx 2.785" o.d. (minus the 02 dimple, and neck down before the rear flange).

The stock resonator?

The stock resonator's inlet is only 2 1/16".



Here's a shot of my stock resonator (left) vs. my Corsa Touring resonator (right).

 

get a 3" dp and call it a day, on the plus side you wont spend money later down the road getting a 3" to replace that 2.5" dp.
having a 3" dp wont cause the drone, its your catback setup that deturmins that.

mine before i went turbo - look at the youtube description for mod list...
YouTube - Cobalt SS wine/exhaust

 

thanks i think i'm going to go with the 3 in catless and if needed i'm by summit racing so i can get a cat.