I'm a new S2 owner, and seriously thinking about putting my money in the right place.
Rather than waste$$ on the typical I/H/E setup, I plan on waiting till I can afford a SC setup.
Whether it's Vortec or Comptech remains to be seen.
(Why? Reliability+Longevity+POWER)

Will I need to invest in an EMS system, if running stock + SC, on stock pulley?
How much would I benefit from adding an EMS of some type (+tuning)?
Is a VAFC good enough, or should I look at higher-end AEM EMS instead?

 

How much boost do you want? 5-7 lbs and a VAFC is alright. More than 7 pounds requires larger injectors to keep up with the additional fuel you'll need, and you'll need an ecu or piggyback that let's you tune injectors to do that.

In a nutshell:
5-7 lbs. = VAFC
>7 lbs. = larger injectors and ECU

 

Actually if you plan on running stock boost you don't need any additional fuel management. Both the CT and Vortech kits are designed to run as-is out of the box.

 

The CT one comes with an additional electronic device that helps the stock computer. I am running the 7 lb pulley and haven't changed my injectors. No problems here.

 

even with Vortech, you won't need anything if you are planning on running stock psi. Vortech Kit comes with an FMU unit so you won't need any engine management...

 

wow lots of discussion on this one and most of them ends with always needing ems. glad to see that some are running vafc, thats what i plan on doing, just with the stock 5.5 boost

 

You'll more than likely main better gains with just the AEM EMS than with the header, exhaust, or V-AFC ...not to mention having a larger margin of safety over those other mods and all while making more power

 

^^^ was waiting for you to chime in on this one haha

 

Cause it's true...do you want me to add a V-AFC to my inventory so I can sell it and make a buck to prove I don't care? I've been saying it for a long while before I ever sold stuff.

All you can do is take away and add fuel with the V-AFC with a broad 4x4 map. You're left with the timing control by the factory ECU and the timing boxes included with the kits. It's not ideal...it's just safe for the majority but not ideal for you. Same reason why I don't understand why people buy thousands on pre-programmed ECU's that make negligable power and have no knock feedback.

 

im running the stock set-up and im going up in boost soon. the EMS is the way to go for the tunability but the ultimate e-manage is also an option thats new but seems to be working for people, you will also retain the factory ecu which will keep CEL and other dash light useless. Im debating wether to get the EMS or the U m-manage,If one was to step up their comptech to 8lbs of boost with an ems would I need to run 550injectors?