The Graves exhaust is a titanium/carbon...
The Graves exhaust is a titanium/carbon fiber work of art, and significantly improved the R1’s midrange and top-end power.
In our continuing quest to improve the performance of the current literbikes, we rounded up some power-enhancing modifications for our long-suffering Yamaha YZF-R1 test unit. These include a Graves Motorsports full titanium exhaust system, a Power Commander V with AutoTune, and a reflashed ECU by ECUnleashed. While each modification can provide significant improvements on its own, it was interesting to see the interactions and how all three combine for a potent package.
The Graves Motorsports full titanium exhaust is not cheap at $2559.95, but this system is not that far short of what you’ll find on Josh Hayes’ AMA superbike. The header is fabricated from mandrel-bent titanium with beautiful welds, while the dual silencers have titanium internals wrapped in carbon fiber. The exhaust has all the nice bits like aluminum flanges up front and a bung for the Yamaha’s (or Dynojet’s) O2 sensor in the midpipe. Shop foreman Michael has now installed several pipes on our R1 and reported that this one mounted easily enough, and saves 12 pounds compared with the stocker. The system is moderately loud for a race pipe, and excessively so if you plan on riding on the street with it.
Inside the Yamaha’s ECU are...
Inside the Yamaha’s ECU are three processors, with more than 300 maps managing a huge assortment of functions. You will need to send your ECU to an ECUnleashed authorized dealer for it to be reflashed—you will get your own ECU back rather than an exchange. The actual process takes just a few minutes to upload the new code and maps, but significant modifications are made
Many racers are abuzz with talk of reflashing a sportbike’s stock ECU, and we just had to investigate for ourselves. ECUnleashed, through its network of dealers, provides this service for $449 and makes a number of changes. The fuel injection and ignition mapping are optimized, both in terms of absolute power and power delivery, to match a specific aftermarket exhaust; various fault codes that may trigger on a race-prepped machine, such as the removal of the steering damper or air induction system, are bypassed; the closed-loop portion of the fuel injection system is disabled, allowing the elimination of the stock O2 sensor and improving the Power Commander V AutoTune unit’s performance (more on that later); engine braking is decreased; the relationship between the twistgrip and the throttle butterflies in the Yamaha’s YCC-T is improved; the opening rpm of the velocity stacks is adjusted; the rev limit is raised; and the idle is raised. Perhaps most importantly, the stock R1 is restricted for U.S. sound regulations by limiting how far the throttle butterflies open at full throttle, and this limitation is removed with the reflash.
That’s quite a laundry list of modifications and bears some further examination. Refer to the sidebar for how the ECU is actually reprogrammed, but as for the why behind all the changes, many are to improve part-throttle control and power. Complete access to the ECU’s programming and multitude of maps allows the fueling and ignition to be changed dependant on not only throttle position, but also the throttle’s rate of change-like an accelerator pump. The company performs loads of testing to get these maps just right for best part-throttle performance. Removing some of the EPA-mandated constraints also makes the bike easier to ride; for example, to meet emissions requirements the fuel injectors are turned off when the throttle is closed. The penalty is more engine braking as well as a sudden surge in power the moment the throttle is cracked open, both of which can be eased by injecting some fuel while the throttle is closed. Raising the idle also helps in this respect. While we had representatives from ECUnleashed visit us at our dyno and reflash the R1’s ECU with a typical map provided to a customer for use with an aftermarket exhaust, the company does have a number of dealers where you can send your ECU to be reflashed.
Dynojet’s Power Commander...
Dynojet’s Power Commander V and AutoTune module fit nicely under the seat. The new version does not require power to be accessed, so it can be programmed even on the bench.
Dynojet’s Power Commander V, an evolution of the company’s piggyback fuel injection tool, has increased capabilities and is more user-friendly than the previous versions. The new unit is physically smaller and easier to install, and offers a finer as well as broader range of adjustment to the throttle position/rpm fuelling array. The company offers a wide range of accessories to work with the PCV, including a quickshifter, an additional module to operate the upper four injectors on eight-injector systems, and the AutoTune module that generates its own map trims based on feedback from an installed O2 sensor. We added the PCV ($369.95) with AutoTune unit ($259.99) to the R1, both of which were simple to install-although the wire for the oxygen sensor was too short to allow an easy, clean installation.