Why is customized tuning important?
A- Every car is different. Depending on your mileage, or other supporting modifications the average “cookie cutter” tune can often cause excessive smoke, large boost spikes, or other unintended side effects. The most common problem with tuning TDI’s is actually the vane system in the turbo. Often the vanes can become clogged with carbon deposits that limit the range of vane movement. The VNT actuator adjustment is also critical. Garrett spec says the actuator should pull the vane lever to a full stop by about 17-22 inches of vacuum. If yours is set too short it will likely overboost. If it is set too long the response from the turbo will be unnecessary slow (laggy). It is estimated that as many as 1 in 4 of the vnt actuators seem to be improperly adjusted from the factory.
