Originally Posted by bmwisthekey

the base fuel pressure is higher on the non-turbo cars, so you can use the nt fpr to bump the fuel pressure up a bit, the problem when running the bigger fuel pumps is that, it over-runs the stock fpr, the passageway for the return is really small, plus they loose their ability to retain the 1:1 rising rate (1:1=boost pressure/fuel pressure)they can get eradic and inconsistant fuel pressure throughout the rpm range, they get can get thrown off quite a bit, again some people get by without upgrading to an aftermarket afpr with minimal problem, most will tell you that a 190lph will be ok with a stock fpr but anything 255 or bigger they usually say its best to get the afpr