Year 87
Model turbo II


can you run 10-12lbs of boost with stock EVERYTHING? I'm talking injectors, fuel maps, turbo etc? If you can, I presume the only thing id need is a FCD & a boost controller. sound about right?

 

S5 does from the factory. 10psi yes, I wouldn't do 12.

 

S5 does what from the factory? Reach 10psi? Don't think so.

 

For peace of mind , here's the issues , along with some solutions

1. The stock fuel system is at its limit around 9 psi (upgrade secondaries and fuel pump), a wideband will show you how lean/rich you're running
2. stock ecu doesn't further retard timing after 9 psi (upgrade ecu)
3. stock ecu has built in fuel cut after 8.6 psi , need at least a fuel cut defender to prevent this, ideally an upgraded ecu/stand alone

 

all really just depends on your car and how well the stock set up is. I have seen some stock cars pull 10psi with just a fcd and be just fine, others have had major issues with fuel with anything over 8. fuel is really the big issue, there is ways to trick the ecu, but no way to trick the fuel pump. a clean fuel filter and sock filter plus clean spraying injectors could be the difference.

to me it's not worth pushing it until you at least get a better fuel pump along with a fpr and a/f gauge. the difference between a well tuned 8 psi and 10 psi in minimal and not worth the risk.

 

i wouldn't run 10psi on a stock engine without checking everything, and changing all the fuel filters, plug wires first.

i would still probably do a fuel pump too.