NorCalCRX hosted a dyno day this past weekend. My engine is a stock 45K mile D16a6 with a DC 421 and AEM CAI, gutted cat and basically stock muffler with a custom B pipe that goes from bigger to stock diameter after the first big bend.

Anyway, there's a bit of a discussion what is causing the 4.5K blip. It's my hunch that its caused by the CAI where the "tuning" of the intake kicks in and creates a resonant velocity stack. This is supported by how the air/fuel ratio leans out. It also agrees with tech articles I've read. It is further supported by the fact that we also added a Z6 FPR which did make it richer, but only seemed effective just before it leans out, more air + more fuel = more power. Lastly, there was one other engine with a CAI shown below (purple), a DX-MPFI which created very similar plots and had the same exact air/fuel ratio trend, only it was a cheap ebay copy of the AEM. The other D16's showed otherwise similar power and graphs at the top end. The blue plot is similar to my engine except it has a short ram Focuz intake with an expanded chamber just before the throttle body. I'm wondering if this is a much better intake.


Anyone have dyno plots of AEM or other CAI that might agree with this?

 

what you say seems to sound true especially with the facts that you have stated, the only better intake id think would be individual throttle bodies