I got the parts for the E28’s new engine today, so i’ll start building it up soon. It’ll basically be a warmed up BMW M30 motor. The block has been crack tested, is bored to 94mm, and is freshly honed. The crank has a 86mm stroke, which will give a capacity of 3.58 litres. I’ve also got a ported E34 M30 head and intake manifold, 2 cams, one which is about 264 degree, and the other which is much wilder, at 304 degrees. It also came with rods, bearings, pistons, about the only things missing are the exhaust manifold, and the oil pump.
I’ve got a few things to figure out before I start building it. If I build it as a naturally aspirated motor, then i’ll use the 304 degree cam, a bigger throttle body, beefier valve springs, and new pistons to give a compression ratio of around 10 or 10.5 to 1. I’ll use a megasquirt CPU to control it, and I would hope to get around 260 – 280 hp at the crank in this configuration.
What I would really like to do though is to supercharge it. It all depends on what it takes legally to register it like that, i’m still trying to suss that out. But if I can do it, then I would revert back to the standard cam and throttle body, and use a centrifugal supercharger and an intercooler. I would get pistons to give a compression ration of 8.5 or 9 to 1, and I would hope to get around 400hp at the crank in this configuration.
Pics can be found Here