So Josh peaked my interst in the smoothboost and I decided to pick one up as I really like the idea of being able to turn down the boost on the fly for street driving.
My D1sc makes about 11.5 at full throttle and on street tires that can be a little too much going through 3rd and 4th, very easy to get sideways.
For those unfamilar SB gives you a wastegate that takes the place of the BOV on the procharger intercooler. Now instead of being operated by engine vac/boost it is controlled by throttle input that can also be adjusted by a control knob. With the knob at max the wastegate operates very similar if not identical to the BOV and max boost is the same. As the control knob is dialed back, max boost is also dialed back, with it set at halfway boost is dialed back to around 2-3psi. Not as much range as I had hoped for because anything less than halfway pretty much keeps the gate wide open. But between halfway and full on I can adjust it to hit pretty much any boost level.
Now for me the best part is being able to have a scramble button that when pushed instantly closes the wastegate giving full boost. With my car I keep the knob set at 2 marks down form max which gives me about 8psi then as the rpms come past 5k mash the button and get full boost and a pretty good kick in the pants. This might be very useful at the dragstrip where with my Nitto drag radials 2nd and 3rd are very tough to keep traction in.
It will also be even more useful next year after I add more fueling and turn the boost up a little more.
Install was pretty easy, wastegate is a direct replacement for the BOV, it is a little longer and was just making contact with the inside of my bumper cover, so I trimmed just a little so it had a bit of space.
Power/ground inside and tapping into the pedal wire at pin #5. Scramble switch just grounded one side and the other to the input on the SB. Running the wires through the firewall was the hardest part. There is also another input on the SB that when triggered will cut all boost, either from a button or an external controller signaling a leanout condition. Also works with your current tune with really no changes.
Not exactly cheap but a well built and does exactly what I was looking for.