The Honda Civic Si has been a shoestring-budget enthusiast favorite for a long time. But it’s hard to deny that it’s been standing pat while it’s competitors have been charging past it – sometimes at a way faster rate of speed. Budget rockets like the MazdaSpeed3, Lancer Ralliart, and Subaru WRX have sucked down a lungful of turbo boost and proceeded to blow the Si’s doors off. Even though the current Si is a hoot to drive, it’s a bit embarassing that a V6 Mustang will blow it’s doors off. Enter the rumormill: when the refreshed 2012 Civic Si hits dealer lots, it’s going to have a new engine under the hood.
Now, that’s not to say the current Si’s motor is a dud. Far from it; it’s just off the pace for power output. The K20Z3 is an all-aluminum 2.0L DOHC motor with VTEC (Variable timing and lift, electronically controlled) and VTC (Variable cam timing.) Like old-school VTEC motors (think the Integra GS-R’s B18C, the Prelude’s H22A, The NSX’s C32B, etc), the K20A/K20Z3 actually has two cam profiles on the intake side, with a high duration profile being hydraulically engaged under certain circumstances. The VTC continually adjusts valve overlap on both intake and exhaust cams, giving the ideal cam timing regardless of which profile the motor is running on. The difference between this setup and “mild” K-series i-Vtec (such as the “fake” Vtec in my Accord) is that the mild i-VTec doesn’t have the secondary intake cam profile or the actuator, just VCT.
All told, the K20Z3 makes a fairly impressive 197 horsepower – naturally aspirated with an 11.0:1 compression ratio. However, it’s not exactly torquey: all that fancy stuff in the head raises the horsepower rating significantly but hardly changes torque at all. Comparing the K20A3 (which was the base-model RSX engine) and the K20A2 (which was the RSX Type-S engine), we find that while the Type S has considerably more horsepower (201 vs 155), torque is nearly identical, with the K20A3 making 141lb-ft @ 4000 rpm, and the A2 making 142 lb-ft at a considerably higher 6,000 rpm.
So why all this talk about boring numbers and valve lift and duration and cam timing? Well, this is why the next Si could potentially rock really hard. It will combine the fancy high-compression pistons and VTEC/VTC head from a K20A2/Z3, with the low-end torque of a K24 (as seen in the Accord, CR-V, etc.) This means it will be basically similar to the K24A2 in the Acura TSX, which has both. Final power output will all come down to tuning – the TSX makes 201bhp (basically the same as the 2.0L Si) but noticeably more torque – 166lb-ft. Will Honda go all-out on this motor and fit higher-compression pistons, a VTec lobe with more lift, and some other tricks? Hopefully! A combination of the K24′s low-end torque with the K20A2′s high-end valvelift roar would be perhaps the greatest four-cylinder Honda has ever put out, and they’ve put out some good ones.
This rumor has been originating from Honda-lunatic enthusiast site Temple of VTEC who has had multiple different sources inside and related to Honda tell them the 2012 Si will have a 2.4L engine under the hood. While Honda themselves haven’t officially announced anything yet, a high-output K24 for the new Si makes a lot of sense, considering how far back in the performance wars the Si has slid. We should be hearing something about the new performance-model Civic soon, considering the 2012 Civics should be hitting dealerships within a few months, so stay tuned.
