I've been wondering how the primary and secondary injectors work on a 13b TT. From what I understand, the primary injectors are smaller, and are used for low rpm use. Then in high rpm, the secondaries kick in right? Also, how come people don't upgrade the primaries as much as secondaries??

 

bump

 

The primaries are smaller, and allow better fuel distribution at lower rpms. The secondaries are larger, and kick in around the 3,000 mark to accomodate the larger thirst of the engine. People don't typically put larger injectors in the primary location because it hampers fuel atomization, and the car can be rougher and less effiecent at lower rpms.