thought you might be able to use this
Will an SR20 crank work in the KA24? What about the FJ20 crank? My goal is to build a 9000 rpm turbo KA.
Sarah: You'll need to do a lot more than to destroke a KA24 to rev that high. Using a long stroke (hehe), the block would break in half around 8000 rpm due to engine harmonics. A 72mm stroke could produce low peak piston speeds that may get your motor to around 9000 rpm, but you'd also need custom valve springs, thicker rods, forged pistons, cams, and keeping your fingers crossed. No KA24 cams on the market right now could handle that type of high rpm running. While the bore centers between the SR20 and KA24 are close and the shorter 86mm stroke could produce an extra 1000 rpm of racing happiness, getting the SR20 crank into the KA24 would still require some machining and modifying. Since the KA24 is based on the L-series engine, the L and Z series cranks would take less machining to fit in the KA24 and come in many different strokes. A L20-B head has an 86mm stroke and is fully counterweighted but doesn't flow much better than a KA24 and probably wouldn't last above 8000 rpm. The Z20 head has the same bore and stroke as the L20-B (85 x 86) and the Z22 would allow you to keep a higher displacement of 2289cc than the other 2.0 crank choices with only 2140cc, but it has a longer 92mm stroke limiting you to about 7000 rpm. Although the JDM FJ20 has a smaller 80 mm stroke, the crank's bore center is too far off to consider. Also, finding one would be like looking for a hooker at a 5 star resort- rare and not cheap. There is a KA20 made in Japan with 86 mm stroke that would bolt in the KA24 producing a 2140cc engine with lower peak piston speeds, allowing you to rev to about 7500 rpm, but still nowhere near your "goal"
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