Originally Posted by quattro08
hmm didn't know that you can fit a mr2 motor in there. but I guess makes sense since it comes from a mid engined car. have to look into that. thank you. but the K series motor is what is used in the honda s2000 and are very popular in swaps
USDM market were first introduced to the K-series with the help of the 2002 RSX, Civic Si, and CR-V.The infamous B-series was nixed to make way for the K20A2, K20A3, and K24A1.
In terms of North American-spec and Japanese-spec K-series engines, the K20A2, K20Z1, K20Z3, K24A2, K20A, and K24A all share a similar i-VTEC architecture. Although engine geometry and ancillaries such as intake manifolds, throttle bodies, and exhaust manifolds may differ between them, they all share more in common than not and make up some of the most desirable K-series engines.
•2002-2004 RSX Type-S: 200 hp, 142 lb-ft torque
The most established of K-series engines, the K20A2 is based off of an all-aluminum block and DOHC, 16-valve cylinder head. Compared to economy-minded K-series engines, the K20A2 features larger intake and exhaust ports, a higher, 11.0:1 compression ratio, and a single-stage aluminum intake manifold that's designed for top-end performance. As is the case with all performance i-VTEC engines, a stiffer, cast-aluminum oil pan is also incorporated that increases overall rigidity.
•2005-2006 RSX Type-S: 210 hp, 143 lb-ft torque
As Acura performed its mid-model refresh on its RSX, a revised K20Z1 was placed underneath its hood for the model's final two years of production. Generally speaking, there isn't much difference between the K20A2 and the K20Z1 other than slightly more aggressive camshafts, a higher-flowing catalytic converter, as well as a larger intake duct and exhaust, which altogether net another 10 horsepower.
•2006-2011 Civic Si: 197 hp, 139 lb-ft torque
The Si's powertrain is unsurprisingly similar to the K20A2 with the exception of its electronics and ancillaries, the most notable of which are its free-flowing intake manifold and drive-by-wire throttle body. The K20Z3's intake manifold, also known as the RBC manifold, which is indicative of Honda's parts naming system, has gone on to serve as one of the most popular bolt-ons for non-Z3 K-series engines because of its exceptionally short runners, straight-through design, and high-flowing capabilities. K20Z3 engines also feature revised camshaft profiles when compared to older engines as well as internal balance shafts, which, in an effort to minimize engine vibrations, sacrifice a bit of power. The K20Z3 also features a deeper, larger-sumped aluminum oil pan when compared to other K-series engines.
•2004-2005 TSX: 200 hp, 166 lb-ft torque
•2006-2008 TSX: 205 hp, 164 lb-ft torque
Honda began producing 2.4L K-series engines for the 2002 model year but didn't release a proper performance i-VTEC version to the United States until the TSX was unveiled. Unlike the K20A's square-bore configuration, 2.4L K-series engines feature a significantly longer 99mm stroke, a 1mm larger bore and, in the case of the K24A2, a lower, 10.5:1 compression ratio. What's more, 2.4L K-series engines are the largest four-cylinders the company's ever produced. Compared to other North American-spec 2.4L K-series engines, the K24A2's internals were made stronger in order to cope with its higher redline, and like most other 2.4L K-series engines, its crankshaft girdle is slightly thicker than those found in 2.0L engines. Like all 2.4L K-series engines, the K24A2's oil pump is counter-balanced, making it less effective at higher engine speeds. Fortunately, the K20A2 oil pump transfers over relatively easily following slight modifications made to it in order to clear the K24A2's thicker crankshaft girdle. Up top, all K24A2s feature cylinder heads similar to other performance i-VTEC engines but with slightly narrower ports that yield increased air velocity. All K24A2 engines also feature single-stage aluminum intake manifolds with long, narrow runners, and drive-by-wire throttle bodies. Several changes for the 2006 model year, like 1 mm larger intake valves and a higher-lift, longer-duration intake camshaft that's arguably better than some Type R camshafts, result in an additional 5 hp. Other mid-model changes include even stronger connecting rods, a more thoroughly counterweighted crankshaft, and additional oil passages within the block, which help reduce windage. A larger throttle body and freer flowing exhaust components were also added.