Hey guys, i've got a rough plan for my twin turbo setup, 1992 350 TPI, I'm not looking for big numbers at all just to play around with it. What boost pressure can the stock fuel system keep up with? I'm thinking like 4psi? Also can someone explain to me exactly how a FMU works? I know it kinda cuts off the return line under boost but how is this accomplished. Also is a boost retard box nessacary under 6 psi? And if i get one do i need a MSD ignition to go with it? Basically i'm not worried about getting boost to the car, just want to make sure it can run with it and i don't go lean and hurt things lol. Thanks in advance. -Mike

 

for smallish boost like that, a retard would not be required in your application. An FMU looks like a big regulator and inside it has a plate, spring, and rubber diaphram. as boost is applied it (via a little vacuum/boost line port), it slowly closes off the return orafice perportionate to a ratio of boost pressure. these FMU's (usually) offer ratio kits installable to decide how many PSI of fuel to how many PSI of boost ( I.E. 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, 10:1 )