Horsepower Inc. Throttle Body/ Injector Swap

10. Matt made sure to use thread-locker on the bracket and sensor fastening bolts. A loose sensor can give false readings that can harm gas-mileage and performance.

13. In addition to significantly more air into the motor, HPI also recommends upgrading the injectors. Their 5.3gps injectors squirt 23 percent more fuel than their OEM counterparts, and the spray pattern is engineered to optimize fuel atomization. Matt inserted the injectors into the fuel rail first.

15. Matt made sure the assembly fit snugly, but was not forced into place, and then he tightened it down.

16. The kit also comes with a set of new intake manifold flanges and gaskets. Matt had them in place in seconds.

17. After the stock sensors, fuel injectors, and brackets were in place, Matt installed the new throttle body unit on the motor…

20. Finally, he attached the fuel line to the injector assembly and attached all the connectors to their corresponding sensors.

21. The successfully installed HPI throttle body looked much better than the stock unit with its polished machined aluminum surfaces peeking out from between the cylinder heads—and it performed better, too!

22. The true indication of a performance-oriented part is how and where it increases power. Most hop-up parts make increases in a single area (like the low-end or top-end), but HPI’s throttle body and injectors increased horsepower and torque across the entire power band, with a peak gain of about 5 lb-ft of torque. You may notice the dip in the 2,500-rpm range—that can easily be smoothed out with some fine tuning. But Matt’s overall response was that the bike felt more responsive and the throttle was much snappier, making the bike much more fun to ride.