Description
The K24Z series
The K24Z1 replaced the K24A1 in the 2007 Honda CRV. The new 2.4-liter engine uses a two-piece, die-cast aluminum engine block with cast-in iron cylinder liners. The oil filter has been relocated to the lower center portion of the block. Inside, there are a forged steel crankshaft and an internal balancer unit. The compression ratio is 9.7:1. The engine also has a 16-valve DOHC i-VTEC head. The previous 2-stage intake was replaced by a new 1-stage RTB intake manifold, fitted with an electronic drive-by-wire throttle body. The exhaust system has a high-density catalytic converter that helps the engine meet emission standards. In 2008, Honda’s engineers had to optimize the K24Z1 to keep it in compliance with higher environmental standards. As a result, the less powerful K24Z4 version became an answer for that.
The K24Z3 debuted in the 2008 Acura TSX. This engine was fitted with chain-driven dual balance shafts, proper i-VTEC system on intake and exhaust camshafts (engagement at 5,100 rpm), high-strength connecting rods, lightweight alloy pistons, and Computer-controlled Programmed Fuel Injection (PGM-FI). The cylinder head is equipped with 31 mm exhaust valves. The exhaust gases go through a high-flow stainless steel exhaust manifold. The CR is 11.0. This description and specs are correct for the K24Z7 as well. The only difference is an application (The K24Z7 was used in Honda Civic Si and Acura ILX).
The K24Z3 for the US Honda Accord had a 10.7:1 compression ratio, produced less power and torque; it was just a K24Z2 engine but with a high flow exhaust system. The true K24Z2 features a 10.5:1 compression ratio, R40 intake manifold, and an integrated exhaust manifold. This engine replaced the K24A8 on production and meets the highest emission standards. The K24Z5 and K24Z6 are the same K24Z2 with minor differences. The first one is available only in China, the second was offered for the Honda CR-V (USDM).