Ok I know this must have been asked like a million times, but how do Honda engine codes break down? like say a nissan (only example)

RB- type of motor
30- displacement
E- SOHC (I think)
T- turbo

So how dose honda do it? or is completly diffrent?

more or less the same.... take the B18C1 for example:
B = series of motor.
18 = 1.8 L
c1 = type of car (in this case GSR)

yup and not to mention your nissan code is wrong anyway

breaking it down its
Racing
Bred
*thats a rumor can't be sure if thats true*
30 size
D<-- DOHC
E<-- EFI
T <-- turbo
T for twin turbo.

Thanks for clearing that up.