The intake system features a resonance chamber located along the fender well that amplifies the sound of VTEC engagement. It's a questionable move, slightly ricer in approach, but not obnoxious. Combined with a pleasing, softened "brap" from the exhaust, the car's respiratory system sounds healthy and hearty, more Kanye West than DMX.

We think there are a couple factors at play here. First of all, either Honda has underrated the new K20Z3, or our hand-built preproduction motor has benefitted from the exacting specifications used during the build process. On the same dyno, a stock 05 RSX (rated at 210 hp on the old system) will put down around 185 hub hp. The best one we ever did (another preproduction car) put down 190 hub hp. Given how strict the new ratings systems are, we suspect our Si is extra healthy, but we'll wait to see what other gains we get, and what production cars do. If you live in SoCal, we'll do free dynos for the first 3 production Si's that come in (310-518-4966).

The fact that the AF ratio goes rich at high rpm on virtually all runs tells us that the K20Z3 is either very temp sensitive, very knock sensitive, or both. The very flat AF curve is also unusual for a factory car (Honda or otherwise), which is one reason why we suspect a little tweaking.

Stay tuned as we begin pulling the car apart and looking for more power.

UPDATE (21:35, 14.Sept.05): I just got a call from Shawn and today another 2006 Civic Si (preproduction, of course) was tested on his dyno. This one had 3500 miles because it had been driven cross country from Michigan. Obviously, the break-in mileage paid off because this car put down 209hp, in a fully stock configuration. With the airbox cover removed, the number jumped to 218hp. Shawn is not near a computer at the moment, so we don't have the dyno plots, and the car isn't ours, so we may not even be able to post the plots, but it's clear that our car isn't a fluke, at least amongst pre-production Civic Si's. jp