First, anyone out there running an aftermarket boost controller with any degree of success on an R60 JCW?


Second, how did you sort this out?


The reason I am asking is that I have a GFB boost controller (still in the box) that I am trying to figure out how to chuck in the car. I spent a good bit of time Sunday in a vain attempt at determining exactly where the vacuum for the wastegate on the turbo comes from and what those bits are doing.


According to what I can figure out, there is a pressure regulator connected to the vacuum tank on the back of the motor somewhere in the vicinity of the intake manifold. The pressure regulator has an electrical connector attached to it, which leads me to hypothesize that the ECU is controlling the pressure converter and thereby opening and closing the wastegate. Here we have my third question: If one was to disconnect the line from the wastegate to the pressure regulator, then allow a secondary solenoid connected to a boost source to control wastegate pressure, (capping or plugging the line coming from the pressure converter,) would that cause a CEL or some other problem? Would it be better to connect the pressure regulator via a T-fitting to the wastegate and then on to the secondary solenoid?


I have a JB+ installed on the car already and did some 0-60 runs with it and found that the boost peaks at around 21.5 PSI with the JB+ at 40%. I've since turned it down to 30% and see peak boost of 20.5 PSI - which is good since there is (according to an e-mail I received from Terry at Burger Tuning, which is staffed by most helpful people who promptly answer e-mail; no joke, e-mailed them Sunday and got a response today,) an overboost cutoff and subsequent forced limp mode at around 21.75 PSI. I never had the car hit the overboost limit, but I was apparently brushing right against it.


The reason I'm asking about the boost controller is that I'd like to bring the overall boost pressures down somewhat while increasing the duty cycle of the wastegate to such a point that it stays shut longer. It seems as though the turbo lags on under heavy accelerator input from a stop until somewhere around 3,500 RPM - both with traction control on and off. This is well below where it feels like it spools in second through fifth gear. I don't have easy access to a dyno, so going out and seeing where it is doing what requires some flat road free of panda cars and disco lights.


Before anyone sidles up and flamesprays me for that last paragraph, I do understand that from idle it may take longer for the system to fully pressurize which can account for the perceived lag in first gear. It's also possible that I require someone to sidle up and flamespray me for that last paragraph. Or this sentence. Or this post. Or my choice of pants. Or my entire existence in the universe up to this point.


I may be a giant idiot barking up the wrong tree, but I'd like to see if someone else has some sort of experience dealing with boost controllers and the JCW N18.


Note: It bears mentioning that Terry also stated that boost controllers would likely not function in the car. So this is / may be more of an intellectual exercise than anything else. In which case, anyone want to buy a GFB boost controller? Totally uninstalled, but the sticker got a little crinkled when I put it back in the box.


tl;dr version: N18 turbo wastegates, how do they work? Is boost controller install dumb waste of time?