I'm doing a TO4 turbo swap, I have 1000cc injectors, an aftermarket secondary fuel rail, and a Walbro 255lph pump. Is it a necessity to go with an aftermarket fuel pressure regulator at the moment? I'd like to get the car back on the street and my funds are very limited at the time. I'd rather wait another month before putting one on. Are there any negative effects with not having one? If so, does anyone have any experience with the Weapon R regulator?

 

It'll probably run, but it will run best if you can regulate the pressure via an intake source.

 

Oh yeah, I'm also using a SAFC-II for tuning.

 

That's exactly what the stock FPR does.

Remember a FPR works similar to a wastegate, in that if it's too small the fuel pressure will go up, not down. So an undersized FPR causes richer mixtures than you want. Unless you measure the fuel pressure and see it's rising too high, you don't need to upgrade the FPR.