avcs is on the jdm sti head's as well as the usdm sti heads. you will need some addtional wires, as well as an ecu equipped with avcs to run it.

 

What is AVCS?

 

USDM = United States Domestic Market
JDM = Japanese Domestic Market

 

AVCS is subaru's version of variable valve timing, like honda's VTEC or toyota's VVTi

 

Its not honda's vtec. hondas vtec has a different set of cam lobes take over after a certain rpm...AVSC constantly regulates valve lift and timing

 

I assume it help with problems such as low end torque and high end flow. How much of a difference does it really make?

 

Incorrect.

AVCS only changes cam timing. Not valve lift.

 

Sorry, my mistake. But besides that avcs is constantly regulating cam timing and vtec just changes over to a diff set of cam lobes at a certain rpm...howstuffworks.com has a lot of info on vtecs if anyone cares...

 

Yep. AVCS is dynamic system. It uses individual cam angle sensors and duty selenoids to regulate the oil pressure that drives the cam timing adjustment mechanism.

 

AVCS = Active Valve Control System and is constantly changing to suit the engine. It only changes cam timing not valve lift.

 

your local subaru dealer