Claviger
Aspiring Student
- Joined
- Jul 25, 2014
- Messages
- 6,934
- Location
- Olympia Washington
- Ride
- '21 Z H2, '14 R3R, '02 Daytona 955i
From the factory yes. They serve multiple purposes, originally they were used to limit power in gears 1-3. On the newer bikes they cut airflow at high RPM.
If used properly they can be tuned to keep intake velocity very high at lower RPM, improving atomization and cylinder filling.
You only need the full bore of the TB path with secondaries open at peak WHP, so below that you can use the need for a narrower pipe to your advantage by closing the secondary slightly. In fact.... that longer pipe but smaller opening to maintain velocity is exactly what all the fancy multi-path car intake setups are designed to do.
Fully removing secondaries vs just commanding them to open to 100% shows no differences in power from 2000 RPM to redline.
