Well Im considering making my own stage kit pretty soon, but I was just wondering what supporting mods would I need to run a 2.9 and 42lbers. I already have an intake. Any help is appreciated, please do not turn this into a flame war of opinions. I would just like to hear everyones opinion without arguements thank you.

I did search

 

When I made my stage kit I just got the stage 1 because you need a code so the dealer can get the GM tune. Other than that I got the stage 2 belt and 3.0 SFPH Non-slip pully.

 

Well Im just gonna get a custom tune so I wont need the actual stage 1 kit. Im looking to save some money by building one on my own. The tune is not my worry, im just worried about what mods I would need to support this setup, such as exhaust,dp,,colder plugs,etc

 

Well if your going with a 2.9 or lower its a good idea to use colder plugs. I would also get headers and a down pipe because the stock one is too restrictive imo. I think the stock collector size on the manifold is less than 2in. Take a look at the zzp header and down pipe combo. Thats what I have in my set up.
http://www.zzperformance.com/cobalt_...=545&catid=155

 

Thanks for the input.....anyone else?

 

2.9, GM belt for precautionary reasons, 42's, NGK's one step colder plugs and a good tune should just about do it.

 

would I need an exhaust, or should the stock exhaust be sufficient for a lil while?

 

just cut the muffler off and you will be good. Seriously though that is my big desicion right now, i think custom 2.5 with the whistler muffler/resonater from zzperformance.com and a flowmaster 50 series muffler. Should sound pretty deep and not too loud...

 

technically you dont need anything to safely run 2.9" and 42# except a tune, stage 2 belt, and 1 step colder spark plugs.

hacking off your muffler will do next to nothing but make noise. the most restrictive point is the downpipe, namely the flex pipe section. cer3bral is right its only 2". a bigger downpipe on a stock catback will do way more than hacking off a muffler. I'm running the 2.9" and 42# on a stock exhaust now. its ok but i will be getting a new DP.

 

What about the 2.25" exit on the manifold?

That is why zzperformance will have me covered with the header downpipe combo

 

50lb injectors
2.9" pulley
HPT
Shorter Belt

=

FUN

 

Thanks for all the info guys, Whats the size of the stock exhaust? 2.25 right?

 

what about the 2.25" manifold collector? its small but its still not as bad as 2".

heres a breakdown of the stock exhaust piping.
manifold = 2.25" collector
flex pipe = 2.0"
downpipe = 2.5" (exc for o2 sensor bung flat spot)
mid pipe = 2.5"
from axle back = 2.25"

 

get 60lbers instead first off.
2.9 is pushin the injectors hard, and if you ever want to upgrade in future your just gonna buy 60lbers anyway.


so 2.9, 60lbers, S2 belt, some colder NGKs and a tune.
would be a nice cheap kit with great performance.

 

I know this is a highly debated topic but wouldnt 60lbs be a lil overkill until atleast runnin a 2.8?

 

i dont think so.
ive seen a 2.8 push 60lbers to 65-75% IDC
so a 2.9 wont be that much less.

better than the 95-105% that a 2.9 can push those 42s to

 

i say you might as well just get a 2.8, thats about as low as you want to go without cooling mods anyway, then go with 60# injectors.

 

True, I have heard of 50lbs and 55lbs, would those be a good medium between 42lbs and 60lbs? If so where can I pick some up?

 

I dont know much about them, but if your sure youll not go much bigger in power...
some 50s would probably be great.

 

Well this car is my daily, and I have heard some horror stories about people blowing up so I was gonna go with a conservative setup. I have considered a 2.8 but it just may be a lil small for me.

 

mine is a daily driver as well, i like it myself.

 

Have you had any problems?

 

nope runs great! and alot stronger then a standard stage 2 or 3.

 

hmm, well ill have to consider the 2.8 a lil more then, have you thrown it on the dyno yet?

 

I'v got a 2.8, 60lb, stage 2 belt, air box mod, the ZZP catless downpipe, AEM UEGO, in the process of custom tuning it w/ HP Tuners.

If you go 2.8, you probably want cooling mods. I'm having problems right now because I don't have any of them. I've seen 79% IDC on the 60lb injectors, and would highly recommend just getting them instead of 42# or 50# etc. If your going for something safe and conservative, you can't go wrong with bigger injectors . The downpipe, I love, I did all my mods in too short a time to be able to butt dyno the DP. The car is quite a bit louder with it, and the ZZP DP is very nicely put together. I also like the idea of pissing off the democrats and their emissions standards hehe. I didn't see a wideband on your list of mods, that's something you probably also want. I would deffinatly recommend colder plugs too, my car runs noticably smoother during acceleration with them.

If your looking for a kick in the pants, a 2.8 (or presumably the 2.9 as well) will give you one .