I have a ?. I hear people down FMU's alot. And im wondering why they are played down so much? I mean i've heard positive reviews from other sites but everyone here seems to dislike them. WHY?

 

nobodys answering so ill answer my self from the best I can tell u all dont like em because the dump to mch fuel true/false?

 

because the way they add extra fuel is by raising fuel pressure. This is bad because your stock fuel system is not made to handle high pressures. Injectors will get saturated(stuck open) if you run them at too high of a pressure. The reason it is better to get a piggy back/standalone is so you can run bigger injectors that can be opened up for a longer period of time giving you more fuel without the high pressures.