Join Date: Dec 2008
Location: Aurora, NE.
Feedback Score: 7 reviews
I copied this from Hondata's page. I think they do a pretty good job describing how to get started.
The ECU produces a square wave at a fixed frequency and variable duty cycle. Applied to a solenoid, the impedance of the solenoid results in a linear motion of the solenoid valve orifice.
The wastegate is normally connected so that manifold pressure acts on a diaphragm, so opening an exhaust bleed valve (the wastegate) at a certain manifold pressure. With a boost controller, additional air pressure is used on the other side ('the top') of the diaphragm, so that more manifold pressure is needed to open the wastegate - so the engine makes more boost. By varying the amount of air pressure on the 'top' side of the diaphragm with the solenoid, the ECU can control boost.
Because the solenoid can only add air pressure to hold the wastegate shut, the minimum boost is determined by the wastegate spring pressure. Therefore you need to run a spring which gives the minimum boost you want. The maximum boost is determined by many factors, but generally will be 2-4 times that of the minimum pressure.
Most important: first set a boost limiter which is the maximum you wish to run, making sure you do not set a limit that exceeds the limits of your map sensor.
Record the boost without the boost control solenoid in place. If you ever want to run less boost than the recorded value, replace the spring and repeat.
Connect the boost control solenoid, enable the ECU output and set the duty cycle to 1%. Record the boost level. Typically there should not be more than a 1 lb increase from the baseline.
You should not use values of 0% or 100% as it will not work.
Add 5% to the duty cycle and record the boost over the rev range. At around 20% duty cycle the boost level should start to increase with each run. Record the duty cycle and corresponding boost level. If the boost spikes or falls off, check the solenoid plumbing.
Keep increasing the duty cycle until you have reached the maximum boost level you/your engine/your turbo/your injectors/the dyno can handle.
Enter the duty cycle and boost values into the parameters 'Pressure vs Duty Cycle' table. This tells the ECU what duty cycle it needs to obtain a certain manifold pressure.
In the 'Boost by Gear' table enter your target boost for each gear. If you want high/low boost settings, enter your alternate boost values in the second 'Boost by Gear' table and set up an external switch under 'Low/High Boost Control'.
Check your gear ratios are correct.
Test by datalogging. The duty cycle is recorded and can be compared to the target tables. Any problems usually arise from the way the solenoid and wastegate are connected - check these first.