Originally Posted by
Sledgehammer
Dropping the clutch at 3.5-4.5k rpms in a 4wd car is a smart idea? Especially in 2nd or third??? I have never done such a thing for fear of either problems with the clutch or the transmission.
It is abit hard on the drivetrain (compared to starting properly in 1st) but it will not cause damage unless you constantly start like that for a considerable amount of time. Besides the MPS is effectively FWD until the front wheels slip enough to activate the rear differential and by that time you should be moving. I am not trying to get you to damage your car and I only suggest that you do this once or twice on any given day (due to the fact that it loads the clutch and you might experience clutch slipping if you don't give everything a rest). BTW I would like to say that I am not trying to get you to floor then throttle and dump the clutch somewhere between 3500-4500RPM, you should be able to hold the revs stable somewhere between 3500-4500RPM with partial throttle then let the clutch out as you push the gas pedal down to WOT, it should be a relatively smooth start. The point is to load the turbo hard and fast.
Originally Posted by
Sledgehammer
Is that the only way aside from dealer involvement to test for such things. What if I installed a better or louder BOV, the one in the MPS/Speed6 is barely noticeable and you need to concentrate to hear it.
No the hard start method is only one way to test. I would first do a simple visual check of the BOV (it's at the front of the engine on the driver's side. just under the plastic cover). Check if all the pipes are connected properly ect. I would like to point out that louder doesn't mean better. Yes you could replace the factory BOV but we aren't even sure that it is the sole problem.
Originally Posted by
Sledgehammer
Also how do you recommend checking a BOV in the engine itself?
The BOV is on the intake manifold after the IC on the drivers side. It should be visible without removing anything. you can visually check that the vacuum line is connected properly to the BOV and to the intake manifold. I believe it is a recirculating system (the vented air is led back to the intake of the turbo), so you might try disconnecting the large air return tube and check if the BOV opens properly (you can do this by having a friend rev the engine in neutral). Every time you lift off the throttle the bov should open quickly then close again fully.
However the BOV may not be the problem. The problem might be with the wastegate activater. You could check the pressure line that goes between the compressor housing and the wastegate activater. I am assuming you bought the car used? maybe the previous owner added a "t" to the line to delay the wastegate opening?
Originally Posted by
Sledgehammer
What is the difference between turbo surge and turbo choke limit?
Well on a compressor map the surge line is the barrier that runs north-south along the left side and the choke line is the barrier that runs along the right side. The main difference is this: with turbo surge you are trying to produce too high of a pressure ratio with too little mass-flow, while turbo choke is when you are trying to produce too much mass-flow with too little pressure ratio.
When a turbo chokes, the shaft speed goes way up but the mass-flow doesn't. The pressure ratio will normally drop and this means that the engine will start making less power. This normally occurs in the upper rev ranges and is a sign that the turbo you are using might be too small. Turbo choke doesn't damage the turbo unless you are somehow able to force it so far into the choke area that the turbo over-revs and falls apart.
When a turbo surges it means the shaft speed is already to high and it actually starts slowing down the turbo. The flow going through the turbo becomes highly unstable and can in some cases start going the wrong way through the turbo (you can hear this as a loud bark that comes from the compressor in severe cases). The compressor suddenly has high amounts of pressure forcing it away from the center housing of the turbo, this is what damages the turbo as the thrust bearings aren't that great (unless you have a ball-bearing turbo which I think you are lucky enough to have stock 
). This normally happens when you suddenly lift off the throttle because that means you cut the mass-flow through the turbo right down. A BOV solves the problem because it allows the mass-flow rate to ramp down more gradually when you shut the throttle.
Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it
Engine torque is an illusion.
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