high flow cat and cat back

[AleroGX04]

ok, so i just ordered a K & N intake and going to order a pacesetter header. was told that i should get a high flow cat and cat back exhaust. after being told what this was, i still wasnt too clear on it. i searched around and its hard to find something when you're not 100% sure as to what you're lookin for. just wonderin if anyone had some sites that i could purchase from. thanks

[Spilner521]

Your best bet would be to have a shop custom make you an exhaust. Get a Magnaflow high flow cat that has an inlet and outlet of 2.25". Have the shop connect a 2.25" pipe from the header to the cat. Then have them make the rest of the exhaust (the cat-back part) with the same 2.25" piping. If you don't want it real loud, get a straight through, perforated core resonator to put in after the cat. Then get a decent size straight through, perforated core muffler with a 2.25" inlet. If you like it loud, just don't include the resonator.

Vibrant Performance makes really nice resonators and mufflers that are straight through for maximum flow. You can get brand new ones on ebay, and they also have mufflers that are coated flat black and look like a stock muffler so you don't attract unwanted attention.

[AleroGX04]

alright, thanks..how much you think all thats gonna run me?

[Alero2k4]

I thought there was a thread a while back that our cars had 2.25 inch piping stock???

[Spilner521]

Stock piping on an Alero is 2".....I measured after I took my whole exhaust off. Depending on the shop you go to, the piping itself all installed will probably be $200-300....plus the cost of the cat, resonator and muffler you buy. So call it around $500 for everything installed for a full header-back exhaust. That's cheaper than some premade cat-back systems.

[AleroGX04]

sounds like a plan, thanks a lot spilner, greatly appreciated

[Spilner521]

No problem...let us know how it goes.

[AleroGX04]

got a link here to a catalytic converter i was lookin at, just wonderin if it will fit.
http://store.summitracing.com/partdetail.asp?autofilter=1∂=MPE%2D91005CA&N=700+4 294923429+4294838974+400636+4294908158+4294869664+ 115&autoview=sku

[Redog]

If you have a downstream O2, be sure to get an O2 sim

[Spilner521]

Yep that one will work perfect...same one I have (except mine is 3"). And actually you won't need an O2 sim...the Magnaflow cats are OBD-II certified and won't throw a "low catalyst efficiency" code.

[AleroGX04]

alright, thanks a lot..you think i'd be better off with 3' or stick with 2.25' or 2.5'?

[alerored04]

stick with 2.25 unless you have some major mods in mind like a turbo like spilner has. For a price comparison my cat back exhaust went on today for $320 including installation, muffler, pipeing, and the tip. And im in ND so the price should be somewhat similar. That was for 2.5" for my v6 as well so its a pretty good mod, so far im really happy with it.

[Alero2k4]

Originally Posted by AleroGX04

alright, thanks a lot..you think i'd be better off with 3' or stick with 2.25' or 2.5'?

Go with 2.5 for sure. 2.25 is not worth the money and if you plan on any mods you will be grateful. Do not get 3" though...only if you were boosted....

[Spilner521]

3" for you would be too big. Mine is 3" because I have a turbo so stick to 2.25" or 2.5". Either one of those is up to you.

2.25" is good for a mostly stock engine you don't plan on modding much more after the exhaust and intake. With the header, high flow cat, and straight through mufflers it'll flow very freely and have good low end torque.

2.5" would be good if you plan any more engine mods in the future as it'll give you the extra flow capacity for mods like port and polished head, cams, nitrous, supercharger, etc.

On your setup the 2.5" will provide more midrange to top end power while the 2.25" will provide more low end to midrange power. Whichever you pick make sure the cat, resonator and muffler are all the same diameter. And I can't stress this enough...for the most unrestricted flow, make sure all resonators and mufflers are straight through.

[Alero2k4]

Haha...thanks for not being lazy like me and actually explaining it Spilner...

[AleroGX04]

thanks a bunch spilner, helps out a lot...especially since im not too knowledgable when it comes to engines. just one more question if i may. not sure on the muffler, i got one here i like, but doesnt say how big the inlet is, just wonderin if you knew anything.

http://www.autoanything.com/exhausts...A2695A0A0.aspx

[Spilner521]

Magnaflow mufflers (like the one you have listed) are the straight through type I was talking about. So yes, you can either go with Magnaflow or Vibrant Performance has some quality mufflers also. And get the muffler with an inlet size the same as the rest of your exhaust, either 2.25" or 2.5".

Try ebay. Usually you can find brand new mufflers for pretty decent prices. This page has the Vibrant mufflers for pretty cheap....and all brand new :http://motors.search.ebay.com/Vibran...r_W0QQfromZR40

And if you want a resonator, go to Summitracing.com and search for Dynomax Thrush glasspack. They're straight through resonators, around 20 bucks brand new for one that's around 20" long and they work really well, and remember, same inlet and outlet diameter as the exhaust piping.

[AleroGX04]

what you think of this one spilner?

http://cgi.ebay.com/ebaymotors/MAGNA...QQcmdZViewItem

[Spilner521]

Yep that one will work and it'll have twin tips too.

[AleroGX04]

so will i have to seperatly buy tips for that?