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2 stage boost on R34 - please prove me wrong This is really bugging me since I did a NEO +t conversion and used a GTT ECU. Nearly every discussion says there is 2 stage boost on an R34 - that over XXXX rpm the solenoid bleeds off some air and gives higher boost. That is except a few posts out there saying that the boost solenoid is always bleeding under normal operation and only closes in limp mode and reverts to actuator pressure. There's been some discussion with the +t guys that the pin 104 signal from GTT ECU can do a similar job to pin 104 on the GT ECU which controls the plenum butterfly valve on the NA engine. The R34 service manual clearly explains the way pin 104 works for the GT - it turns the solenoid on at idle and off above 3500 rpm. But all it says for GTT pin 104 is that it's off at idle and at approx 2000 rpm it comes on when the engine is suddenly raced. Where is it documented apart from hearsay that it switches at over XXXX rpm for the GTT? To satisfy my curiosity I went out for a drive with a voltmeter connected across the solenoid plug from pin 104. Under any acceleration ("engine raced") the voltmeter showed a steady voltage (solenoid open). As soon as I relaxed the throttle the voltage dropped to zero (solenoid closed). I took it right through the rev range and as long as it was above 2000 rpm and accelerating the voltage never changed at 4500, 4700, 3500 or any other rpm. If I relaxed the throttle at 5 or 6 K rpm then the voltage dropped back to zero - it didn't maintain the 'solenoid on' voltage even at those high revs. So what I saw seems to agree with the service manual. But where is the idea of two stage boost coming from, I just can't see how it would work on the basis of what the manual says and what I saw in my test. I hope I'm wrong and can have it explained why so I can try using pin 104 to control the butterfly valve.