Installation and use of the TCFI IID is simple, since the ‘07 Harley exhaust systems come oxygen sensor ready.



The TCFI IID from Daytona Twin Tec comes with all the sensors and software included. It’s all available from Drag Specialties.


The TCFI IID is currently the only aftermarket ECM available to fully support the new 2007 Harley-Davidsons.

t’s here, and not a moment too soon. The Daytona Twin Tec TCFI IID is the only ECM (Electronic Control Module) currently available in the aftermarket fully supporting the 2007 Harley-Davidsons. Installation is a snap too, since the exhaust systems on these bikes already have provision for the oxygen sensors. And if there were ever any bikes that could use some help in the engine-management area it’s the new Harleys. Here’s why…
     Last year Harley-Davidson introduced a new throttle body, fitting it to the fuel-injected Dynas. It’s on all the bikes now. Along with the throttle body came a new ECM using closed loop technology controlling the air/fuel ratio (AFR). A pair of narrow-band oxygen sensors, one in the front pipe, one in the rear, function over a very limited 14.5-15.0 AFR range, keeping the engine at 14.6 AFR under all conditions except wide open throttle. This is an extremely lean condition for an air-cooled engine resulting in a noticeable surge under part throttle and hot running. On top of this the new Harley injectors themselves are smaller, delivering just 3.9 gm/sec versus the 4.2 gm/sec of the earlier 2001-2005 models. Most 2006 models have narrow 8-degree spray pattern injectors, too, adding to the problem.      
     Harley-Davidson has even issued a Service Bulletin about this, listing replacement injectors with a 25-degree spray pattern. And of course the 2007 Harleys have the new 96-inch engine which, due to its longer stroke, tolerates less spark advance creating yet another tuning problem. The’07 bikes also have a 6-speed transmission with a 6th gear indicator light on the speedometer, signaled by the ECM.
     Daytona Twin Tec’s TCFI IID addresses all of these issues. The stock narrow-band oxygen sensors are replaced with wide-band sensors functioning over a much broader AFR range, including wide open throttle. With the TCFI IID you can set the AFR to any desired value from 10.5-15.0, and do it in every RPM and throttle-position cell from idle to WOT. In most cases, however, the TCFI IID will eliminate that tedious job of manually tuning the fuel tables and do the work for you, auto-tuning the system for optimum performance and efficiency based on feedback from that pair of wide-band sensors. The auto-tuning happens right on the road under realistic operating conditions, too. No dyno time required. The TCFI IID even clicks on that 6th gear indicator light on the speedometer face.
     Daytona Twin Tec’s TCFI IID, sensors and software included, is available right now. Drag Specialties has it in stock. For more information about wide-band sensor technology, visit www.daytona-sensors.com/tech_wego.html. For more information about the TCFI IID, visit www.daytona-twintec.com.