I have been touring between header and downpipe combos for about two months now and recently decided to go with the ZZP Mid-length combo. I had my mind set on 1 3/4" primaries for the header and 2.5" de-catted downpipe.

Until recently I've been rethinking this setup. My buddy with a fp green turbo'ed STi told me to go with 1 3/4" primaries for the header and 3" downpipe with 2.5" exit de-catted. His theory is because my 2.4L is naturally aspirated then more air flow through the exhaust means more HP and torque. Compared to turbo cars, they need back pressure whereas my naturally aspirated car doesn't.

What is your opinion and should I get the O2 bung with plug? What are your opinions of a de-catted downpipe?

I currently have a Megan Drift-Spec catback with 2.5" piping and 4" tip.

Thanks.

 

don't listen to your friend, and i would never take advice frim him/her.

i would def. get the 2.5" dp, do NOT get the 3".

with an exhaust it's all about the velocity. untill you're getting more air IN, you don't have to worry about getting such a big exhaust. doesn't make sense. stick with the 2.5

 

I told his that his theory was bogus. What about the 1 3/4" header? Should that be fine?

 

i think u should buy my high rise wing

 

Go 2.5" all the way for sure.....3" is overkill on our 2.4's unless you plan on doing the supercharger swap. As for the de-cat downpipe, I have an XTC 2.5" de-cat and I love it. Love the way it sounds, love the way it performs. Just be careful and find a bs place to get it inspected. Also, you'll experience a CEL with the de-cat downpipe, but its no biggie, and HP Tuners can turn off the rear O2 sensor entirely and eliminate that problem.

 

Do you know remember how much the cobalt addiction header and xtc downpipe cost after you finished your transaction?

 

i've had both the cobalt addiction setup, and the zzp setup, and think zzp is the way to go without question.

 

if ur gonna get the 3 inch u should be boosted in some form..in my other hand i got the 3 inch dp but im gonna be supercharged next month

u have the excact setup as me good luck bro

 

$200 for the v1 header
$180 for the 2.5" de-cat downpipe

$380 + shipping. Not a bad deal if you ask me.

 

1 3/4 primaries are too large for a stock 2.4L... you'd lose more low-end than its worth for the minimal (if any) gain at redline.

1 5/8 max. http://www.superchevy.com/technical/...exh/index.html