b20 to b25 or b27????

[swainerjim]

hi i have a G reg 320i and want to fit either the b25 or b27 what bits would i need? ie just engine and inlet and exhaust manifold , ecu ?
will it fit my gearbox, starter,alternator, wiring loom?
cheers

[gromgsxr]

you can use the box starter flywheel clutch rad loom pas and alternator ect think you need the correct ecu and also the afm the b25 injectors and fuel reg and inlet manifold n throttle body as well i believe. pretty sure the exhaust main is the same.

[Brianmoooore]

They will fit your gearbox, although your existing box isn't the one BMW used with the bigger six pots. The 320 gearbox is weaker, but should still be OK with the higher power and torque, and arguably has better ratios.
The same can't be said about your differential - the 320 uses a 'small case' diff., which has been known to break with 2.5 or 2.7 power. The ratio of your existing diff. is matched to a torqueless 2 litre, and needs to be changed anyway to make use of the much greater 2.5 or 2.7 low rev. 'grunt'.
For facelift stuff, exhaust manifold, starter, alternator, all engine sensors except the AFM, and wiring loom are all the same. Engine ECU is the same apart from the main 'chip'.

[swainerjim]

cheers guys some good food for thought

[gromgsxr]

my 320 diff clutch and box has lasted a year so far with a b25