I am going to be turboing my 420a soon. I have an adjustable FMU but i dont know if thats the route i wanna go and i have seen all the posts about how the SAFC wont work. I am looking for something thats not outrageous in price because im kinda on a budget.

when you say adjustable FMU, what exactly does that mean. what do you have?

Uh tell us your hp goal first.

Originally posted by 420agreenvilleSC
when you say adjustable FMU, what exactly does that mean. what do you have?

Its a BEGI FMU looks like this

If you already have that then thats the least expensive way to go. The SAFC works on our car but because of the stock computer cutting fuel any time it see's a positive map signal you have to put either a voltage clamp on the map signal or use a Missing Link which is a check valve and vents the positive pressure to the atmosphere. SO that being said the SAFC just bends the map signal but if you are tricking the ecu into not seeing a positive map signal then neither is the SAFC therefor you can't use it when in boost. You can use it to scale down larger injectors so you can idle but thats about it if you going to boost. My suggestion is since you already have the adjustable FMU then use it, they have been prove to work nicely to around 15psi. If you want more down the road or you want something a little bit nicer sell some spare parts you have laying around and get MSnS or wait and save your nickles, dimes, pennies, and sell your soul and get Port Fueler from Hahn.

that FMU's fine. not the best, but it'll do its job.

Another option to the map sensor problem is to change your map sensor. I use a MSD 2 bar map sensor for my programmable DIS2 box and also have it feeding the SAFC/stock cpu it's signal which will never reach voltage for fuel cut. That will also let the SAFC have a little more control over your fuel system.

On another note, I always had problems getting with that FMU to keep the base pressure low enough. Even with the main adjustment backed all the way out, my pressure wouldn't drop below 84 psi. I went with an Aeromotive regulator and plumbed my own 3/8" return line back to the tank. Now my pressure stays where I want it.