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Transfer Time Area Programme
This programmme calculates the specific time-area for the transfer ports of an engine. From this information the programme calculates the potential power capability of the engine. If you require an increase in power from your engine, you can quickly ascertain what modification will give you the required increase.
Example - Tuning a 50cc Engine
For this example we are using the 50cc engine from our exhaust time area example. First measure the transfer port opening timings. This example has 4 transfer ports with timings of 117 degrees after top dead centre. The first pair of ports have an effective flow width of 11 mm for each port. The 2nd pair have a flow width of 10 mm.
None of these ports are "booster ports" - transfers that face the exhaust port usually with an upwards inclination angle of 45 to 65 degrees. Hence do not check the booster input. The output from running the transfer time area programme is shown below.
The potential power output based on the specific transfer time area is 15.61 hp at the crankshaft - labelled 1 in above image. As this value is greater than the potential 14.12 hp based on the exhaust blowdown, it is evident that the transfers do not need modification.