carnut222;c-151838 wroteWith fuel pressure, the maps are designed to work with the OE pressure, so potentially the car will run rich all the time with higher pressure. The FI can correct to some extent with the feedback of the O2 sensor (more so on LH2.4 with the learning than LH2.2), but it won’t be ideal. If you run higher boost, the fuel pressure will increase linearly with boost pressure due to the vacuum/boost hose on the fuel pressure regulator. I put a supercharger on our 88 240GL (running LH2.2) and I ran a very aggressive rising-rate fuel pressure regulator to make sure it had plenty of fuel under boost. Even then it could have a bit of pinging under boost of 5 PSI as the stock (non-EZK) ignition couldn’t retard enough. Anyway, a rising-rate fuel pressure regulator might be an option to consider as it only alters the fuel pressure when you’re under boost, which is where you’ll need it if you’re going to go above stock boost pressures. You may not even need it depending on how high you go with boost...I.e. keep it sensible! ;)
A supercharger on a GL sounds wild haha. Thanks mate I’ll do some research on the rising rate regulator. Should I look into getting a 3” AMM from a 760? I plan on running about 15psi which is about max for gearbox
