Originally Posted by ppenguin2134
Ok, I now have all the new parts installed on my GSR: DC 4-1 header, AEM cold air intake, Greddy Evo2 cat-back, and Carsound cat. The other night my friend pointed out that it sounds like Vtec is engaging at 4,500rpms. I don't have a VAFC so theres no way I could have changed it. I mean @ 4500rpms my engine really opens up. Anyone have an answer for me on whats going on with my car?
The sound you're hearing at 4500rpm± is that of the secondary intake runner valves opening.. just before the VTEC switchover.
The CAI has eliminated the baffles and resonators that otherwise mask that change in the intake note.