M50 or M52 engine,which is better for a turbo build?
im thinking about turbo-ing the 325i. the m50b25 is iron block and the m52b28 is alloy with a nikasil bore. ive heard the m50 is stronger for boost but the m52 has more capacity. whats the go for a reliable 250-300kw street setup? anyone done either in australia?
The M50B25 iron block is the proven choice for turbo builds. The iron block handles boost better than the nikasil M52 without needing a sleeve job. The M50 rods are forged from factory up to 1995 which saves money on internals. For 250-300kw on pump fuel a Garrett GT3076R turbo, 550cc injectors, and a Link or Haltech standalone ECU will get you there reliably. Budget $8,000-10,000 all up for a properly done setup. The M52 can be built to the same level but needs more work to get there.
m50 all day. iron block takes boost without any drama. same reason the rb26 in my gtr uses an iron block, you want the strength when youre pushing boost. the m52 alloy block needs careful management of cylinder pressures. for a street car you want reliability over the extra 300cc.