Zugga

I perused a little bit trying to make sure I wasnt bringing up an old topic, but i would like to put full header back 3'' exhaust and i cannot seem to find anyone who does it. I know hahn has Cat-Back 3'' exhaust but is that a header and downpipe for it as well? and then would a 3'' header fit on the block? idk, lol any help, helps!

NWAE Cobalt

iTrader: (1)

clear image is having a sale on them

D4u2s0t

why do you want a 3" exhaust?

BLAZIN07SS

iTrader: (7)

Vibrant FTW. 3 inch collector, 3 inch downpipe with cat, 3 inch cat-back...but your a 2.4, this would hurt your performance unless you pushing a lot of power. 3 inch exhaust is overkill on a 2.4

Zugga

yea, i intend to supercharge the car, this will be down the road of course i am jsut trying to get a grasp on my prices for my entire project. thanks guys!

Tazmanian_Dvl

Unless you're over 275-300whp you're probably actually hurting the performance of the motor with the 3" exhaust...

Jimmys2007CobaltSS/C

iTrader: (1)

its more like 250 whp and up according to hahn

mike25

its overkill on a supercharged vehical too. unless your making serious power

Zugga

how big should i go if i supercharge my 2.4?

Tazmanian_Dvl

2.5"

OniMirage

there was a chart posted here in the past which showed the flow rates for various sizes even dual exhaust and unless your in the less than 300 range a 2.25 would be fine if your 300+ up to i think it was 350 or 375 a 2.5 was good and anything more then a 3" was essential.

ColeJJones

i run a full 3" exhaust. zzp 3" dp to Hahn 3" non-cat back

lsjwannabe

iTrader: (1)

:looks at dyno sheet's:

:looks at exhuast:

:shrugs:

OniMirage

keep in mind if your going big you need big power otherwise your going to lose a nice chuck of torque and may not gain much return in horsepower.

Tazmanian_Dvl

exactly and on the street torque is king!

lsjwannabe

iTrader: (1)

Tell that to the honda guys they click off 14's with 130 tq

Tazmanian_Dvl

WOW 14's I'm sooooooooooooooo impressed...NOT

lsjwannabe

iTrader: (1)

You guys place a little to much concern on low end tq, you know effectivly what you are doing by increasing the pipe diameter?

OniMirage

your supposed to increase volumetric flow but too large of an exhaust and you will lose flow, better than a restrictive small exhaust yes but not better than an exhaust that has sufficient flow for the amount of power you are putting out.

Tazmanian_Dvl

not to mention that when you change pipe diameter you change the back pressure in the exhaust system which can affect performance...

lsjwannabe

iTrader: (1)

Both good points, just remember our car has a postive displacement blower it does not need all the low end tq in the world.

OniMirage

true but if your not making big power your also not putting out enough exhaust gases to justify the larger piping and if your not meeting the flow rate your only hurting yourself. Rather than going straight to a larger exhaust system it would be best to optimize your entire flow system with a header, dp then the tail end of the exhaust system. Most people do this backwards or all at once but the idea is the same going big without the ***** to back it up makes you loud within minimal gains so you will sound like a honda with a 3" exhaust driving in a school zone

lsjwannabe

iTrader: (1)

Forsure, i agree with everything you just said except for when to switch over to a different exhuast by power. The stock muffler is restrictive as seen by dyno gains of just the cat back switch. I say after 250ish go 2.5" and around 300 go with a 3"

Tazmanian_Dvl

LSJ I agree. pretty much what I said earlier.

PikerAA

So if someone wanted to get a full 3" exhaust before they went to upgrade to over 300 hp? Would this hurt the engine or would it just be a power loss? For example... I am interested in the new turbo kit from ZZP but they say you should get the 3" system first... and I definitely can't afford both right now so how should I go about doing this... if I do it at all?