Here is the 13C inlet before any opening up.

The 13C is a small turbo. It was used to lower boost threshhold...to reduce "lag".

The TD04H turbine housing is a 6cm^ housing. That makes it roughly equivalent to a .41 A/R aspect ratio. It IS small.


Trying to modify the 13C itself to improve flow through the turbine would be very difficult. The only real way to increase the flow would be to either extrude hone the turbine housing, or go with a larger...7cm^ [~.49 A/R] or 8cm^ [~.57 A/R], or even a 9cm^ [~.65 A/R]...turbine housing. To get more flow --both turbine flow and compressor flow-- would be easier to accomplish via changing turbos.

Since I am not going to be replacing this turbo anytime in the near future, the goal at this point is to do some porting work on the turbine housing inlet to improve the flow into the turbine housing and on up into the scroll area; and to port the wastegate opening to allow more flow past the wastegate when IT is in operation.

If I can improve the flow into the turbine scroll...where the exhaust gases actually perform the work of spinning the turbine wheel, then I will have made the job easier for the turbo. Better flow through the wastegate also helps things: the exhaust backpressure will be reduced.