Ok, as is most topics information is scattered all over the place and most people would become discouraged from endless searching, so here is what i hope to do:

Those of you in the know, post here as to which modifications require the ECU to be tuned, and which ones do not. As you post I will bump them up here so we can get a running list going. That way people only need to look in one place to see if they need to tune their car or not before they do their next mod.

I want to cover everything from intakes to pistons, internals/externals/bolt-ons/meth kits you name it. So those of you with the experience, time to regurgitate some knowledge.

Thanks in advance!




Stock Pulley Size is 3.346"

Stock System can handle the 3.30"
Colder Plugs 3.20"-3.10"
Colder Plugs and larger injectors (42-44lb) with tuning for 3.00-2.90
Colder Plugs and larger injectors (50-65lb) with tuning for 2.80-2.70
Colder Plugs Snout machine and larger injectors (65lb+) with tuning for 2.60 or smaller.

Courtesy braineater


If you change make any type of airflow change or anything that would effect your air/fuel mixture (example: water/meth injection), you should also tune your computer for a proper air to fuel mixture and quite possibly ignition timing depending on the situation.

Courtesy NJHK

 

this is from cobalt performance parts, hope it helps.

Stock Pulley Size is 3.346"

Stock System can handle the 3.30"
Colder Plugs 3.20"-3.10"
Colder Plugs and larger injectors (42-44lb) with tuning for 3.00-2.90
Colder Plugs and larger injectors (50-65lb) with tuning for 2.80-2.70
Colder Plugs Snout machine and larger injectors (65lb+) with tuning for 2.60 or smaller.

 

Plain and simple:

If you change make any type of airflow change or anything that would effect your air/fuel mixture (example: water/meth injection), you should also tune your computer for a proper air to fuel mixture and quite possibly ignition timing depending on the situation.

 

NJHK, what about pistons or any kind of headwork, say I went with new cams, or diamond pistons, or bored out with larger pistons, or sleeved it, or any number of such things. Basically trying to approach this from the position of knowing little or nothing of motors

 

Everything you just mentioned will effect how much air will be either drawn in or effect the air/fuel mixture in some way. You will DEFINITELY need a tune.