So yeah, I'm a boost noob and I was wondering if someone could tell me a proven amount of boost the stock fuel system of a 99 em1 would handle? Not an opinion but a proven number... I know its not a lot and I know I need to upgrade the fuel system and I'm going to, I just don't want to push too much and lean out the car and damage my internals. Thanks in advancre

 

boost is irrelevant. power is the constant. if you are talking in terms of fuel pump, it was designed to make the power the car makes stock. thats about it. the stock pump may make more but you are asking a lot out of it.

FWIW, i made 540 on a single walbro, aeromotive reg, and stock lines to the filter, braided to the rail, and a braided line to the reg and return all -6.

 

so i should be fairly safe if i run only a walbro 155 for now then? im just trying not to jack my car all up seein as its the only one ive got at the moment

 

Get a walbro 255 and maybe new injectors, it depends on your goals. I made 450whp with a single 255 and new injectors. The rest of the fuel system was stock

 

awesome, thanks guys!

 

a single 255walbro will allow 760 hp at 17.5 volts (cars are 12 so youll need a boost a pump) without it, 500 ish.