16-valve, 1.5-liter i-VTEC
The CR-Z is powered by a 1.5-liter i-VTEC® 4-cylinder engine with Integrated Motor Assist IMA®. The CR-Z operates its 16 valves via one overhead camshaft, employing rocker arms for each exhaust and intake valve. In addition to providing variable intake-valve duration and lift profiles across the rpm range, the CR-Z's engine closes one intake valve at low rpm, running with three valves per cylinder until the engine crosses the 2300 rpm threshold, after which the engine resumes four-valves-per-cylinder operation. This makes the engine run more efficiently in the very bottom end of the power band. As an added bonus, the engine also produces an impressive exhaust notehow many hybrids can say that?