Originally Posted by STI8U
Let's not forget that the difference in USDM/EDM/JDM AVCS maps may be due to differences in the centerlines of the intake and exhaust cams between the various designations.
W00t. Somebody finally said it. There are cam differences between the motors so that does play a roll in the overall AVCS utilized.
In an NA motor you actually want overlap at high RPMs. It helps pull in the new intake charge. Turbo motors are different. However, what Clark *might* be talking about is that the USDM STI boost drops dramatically because the turbo becomes less efficient. AVCS in that area could actually help to create more power. If the stock turbo didn't drop off then keeping AVCS low or zero would be the best bet. However, the stock turbo DOES drop off.
BTW - this is one of the better AVCS discussions so far. It's always helpful when tuners post and start disagreeing because more information is posted. I guess it's time to start increasing AVCS as the turbo gets more inefficient.