Posting the results of a flow test comparing the DBV2 charge pipes with the stock GTI pipes prompted a question about the volume increase and potential increases to turbo lag.
With both sets of charge pipes available I set out to determine what the respective volumes are, and estimate if the difference is likely to affect turbo responsiveness.
To determine the volume all of the pipes are joined, and in place of the intercooler a short length of charge pipe from a different setup is used to connect the turbo and throttle body sides. The closed piping is then filled with water and the quantity is measured.
The stock piping holds 4.5 liters of water.
Next the DBV2 charge pipes are similarly arranged and filled with water.
The DBV2 charge pipes hold 5.25 liters of water.
The 0.725 liter difference in volume is identified on the 1 liter measuring cup.
In terms more relatable to the charge pipes, the difference in volume between the stock charge pipes and DBV2 pipes is equal to the driver side intercooler hose, shown below:
Addressing the question of the affect this change in volume may have on the turbochargers boost onset, the 0.725 liter volume increase is equal to 0.0265 cubic feet.
At 1500 RPM the pipes have flowing through them approximately 47 cubic feet per minute, or 0.78 cubic feet per second. At that flow rate how long does it take to fill an additional 0.0265 cubic feet? Approximately 0.034 seconds.
The difference in volume between the charge pipes does not seem large enough that it would cause a detectable increase in the time for boost pressure to build up.