The stock fuel system cannot support anything close to 500hp. In fact, it starts to bump up against it's limits much earlier than I would have ever thought given all the power numbers we routinely see. And any one weak link in the system will have a negative effect on the other components. We have been seeing evidence of this for a while with respect to fuel rail pressure datalogs and random fuel system hardware failure. For some time, I've been recoding seemingly innocuous behavior that I couldn't quite explain through DME mapping alone. I think some applications just make it too easy to make power. This is one of them. And when new technology is released (BMW direct injection), the steep initial learning curve makes it too easy to just put the usual concerns on the back burner and to just make power instead. And on top of that, the fuel system design in the n54, right down to the electrical connectors, high operating pressures, EPK/HP diagnostics, closed loop pump control, mounting hardware, etc,. make "throwing in a Walbro" impossible. So a more serious effort is required. But I agree that this should't have taken 4 years to do. I'm a bit embarrassed.
Last edited by shiv@vishnu; 04-07-2011 at 10:42 AM.