All,
Apologies for the lapse in communication and therefore updates; there is a very good explanation for such - brace yourselves. Approximately 1 week following the conclusion of the build, several operating concerns arose, beginning with an entirely erratic throttle response and a lack of boost and power. Naturally, I began with mechanical diagnostics and found several boost leaks, specifically from the blower exhaust to the engine block. We rectified this as well as a few other leaks and retested. Unfortunately, the power issue persisted; the car was (and remains) under-powered to stock form. Given that we employed the ESS N52 kit for the Z4, the package did not present a mechanical blow off valve, rather (and somewhat cleverly) utilizes cam phasing to build and relieve boost. Diagnostics did show that the exhaust cam was not phasing and was in essence stuck, which would not allow the car to build boost nor access ECU maps that would allow for normal power generation. So, we replaced every freaking VANOS component, and yet, the issue remains.
Keep in mind, two separate shops have attempted to fix the issue, GMP and more recently, Performance Technic, both of which are quality operations. Now, for the predicate of my tirade: after having examined all possible mechanical failure modes, what remains must be ECU and / or tune related. And now, onto ESS - who prior to this adventure, I had a fair amount of respect for. To be fair, they were clear from the beginning in not warrantying the custom application, nor guaranteeing that it would work. However, one would think that they would be intrinsically motivated to support the initiative given that I in essence performed R&D that would potentially and considerably expand their addressable market for the N52 kit.
Let's begin with the tune circus. The first tune dispatched bricked the car (I only recently found out about this amidst a discussion as to whether or not the ECU is permanently corrupted). The second tune worked, however only for a week or so prior to the aforementioned operating concerns arising. Throughout this process, I have challenged ESS to determine whether or not the issue could be tune related, moreover whether or not the supplied files were in fact appropriate to the X5 platform; furthermore, if not, to develop one that is. That I would gladly compensate them for writing a custom tune goes without saying - clearly, I am not cost sensitive. Rather than a definitive answer, I have received vacillating responses and half-ass attempts that smack of either incompetence or risk mitigation (which is absurd as I clearly understand and appreciate the bespoke nature of the project - hence, all risk lies with me, not them). In the final analysis, I have employed my good friend and BMW soothsayer Raza of RK Autowerks to consult and rectify the situation.
I am convinced that the initial ESS tune (that which bricked the car) resulted in irrevocable ECU damage, and is the root cause for the several operating concerns that masqueraded as mechanical failures. I am unsure as to the impact of the second tune, but through keen powers of deduction, can conclude that it did not help the fare. We will now replace the ECU, write a bespoke tune and evaluate performance thereafter.
Caveat Emptor comes to mind, as does Lemon's law. My optimism for the project remains,
however I want to make it perfectly clear to any other remotely considering a similar SC installation: the ESS kit, but for the blower itself, IS ENTIRELY INCOMPATIBLE with the e70. Furthermore, ESS will not, implicitly or explicitly, support bespoke efforts to rectify what should be a relatively mundane matter of writing custom code. I won't disclose what the diagnostic process has cost, yet this warning should serve as sufficient notice. I will provide an update after the ECU and tune work has been completed. If that doesn't work, I am going straight to Stage-II, which will be a fully bored and stroked motor, still deciding on the platform.
Not for the faint of heart indeed, but fun nonetheless
