Originally Posted by mike85-325e
wut about for a 1991 318i?
Since we now know that the stock 325i injectors are no where near maxing out at stock hp levels, I would assume the same to be true of the 318i.
To be sure:
1) Find out stock injector size.
2) Use online bsfc calculator to calculate your engines bsfc. (most BMW engines are well below 0.45 bsfc)
3) Use online injector size calculator and use the bsfc you found in step 2 to see what size injectors are optimum for your hp level.