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.
The PCV interface is quite...
The PCV interface is quite intuitive and a step easier to navigate than the previous PCIII. From here, fuelling can be changed and the AutoTune can be set to suggest map changes based on an array of air/fuel ratios.
The PCV has inputs available that can be used to assist with the tuning process: An external switch can be wired in to select between two stored maps; a speed input allows the unit to detect what gear the bike is in, and enables different maps for each gear; with this feature enabled, different maps for each cylinder can be accessed, for a total of 24 maps on the R1; an analog input can be used for temperature or pressure sensors, from which the maps can be offset for use with nitrous or a turbocharger; and the accelerator-pump feature is carried over to the new unit. We were most interested in the AutoTune accessory, which is an additional box that plugs into the main unit and generates suggested changes to a selected map based on readings as you ride (or run the bike on a dyno) from a supplied O2 sensor.
You’re probably asking (as we did), why would you need the Power Commander as well as the ECU reflash? To account for changing conditions such as other modifications, weather or fuel, the PCV and AutoTune can be used to subtly adjust the fuel injection as needed, rather than continually reflashing the ECUa costly prospect. An additional symbiotic relationship is that because the reflashed ECU disables the stock closed-loop injection function, the AutoTune is not constantly fighting the stock ECU and over-compensating. As such, the AutoTune function works better and is more accurate. So, we headed to our SuperFlow dyno with both installed on the R1.
This Serial Suite tuning kit...
This Serial Suite tuning kit from Piasini Engineering is what’s used to perform the reflash. Wired into the ECU’s connector, the new software and maps were uploaded to our R1’s ECU in eight minutes. The small USB stick contains maps for a number of different motorcycles and tuning combinations, which are constantly being updated.
First up, we ran the bike with the stock ECU and no Power Commander, and saw a healthy increase in power across the range with six more peak horsepower from the exhaust alone. The midrange is nicely filled in, and there is slightly more power past the peak. Reflashing the ECU bumped peak power by an additional four horsepower, now 10 more than stock and even more past the power peak. You can see on the dyno chart that the rev limit is higher on the reflashed ECU (raised from 13,750 to 14,200 rpm), but a nice touch is that the limiter is softer, gradually cutting fuel and spark rather than abruptly. Adding the Power Commander on its own did not noticeably increase power on the dyno, but note also that the ECU reflash did not increase power below the original power peakafter which the stock bike is restricted. Using the stock ECU and the Power Commander did fill in the small dip in the power curve at 5000 rpm, almost exactly as the reflashed ECU did.
Our R1 picked up more than...
Our R1 picked up more than 10 peak horsepower with significant gains across the range and an almost 20-horsepower increase past the peak. Note that the rev limit has been extended, and that the power curve is smoother. Adding the Power Commander V did not appreciably change the dyno chart.
Following the dyno session, we set the AutoTune unit to gather data as the bike was ridden, and used that to tweak the fuel map accordingly. Our modified R1 is definitely more powerful than stock throughout the rev range, and riding it showed that it is more responsive as well, with no jumps or dips in the power. While the bike is now so responsive to throttle inputs that even more than usual care must be taken on corner exits, that care is not so much to ease the stock bike’s sudden lurch in power as the throttle is opened, but rather to keep the front wheel on the ground and the tires in line! The modified R1 is an impressive package, with the Graves exhaust, Power Commander and reflashed ECU combining for some potent results. Now we just have to scrounge up some more modifications so we can keep this bike in the test fleet for a while.
The Yamaha R1 ECU has two...
The Yamaha R1 ECU has two Renesas processors with more than 300 maps to oversee the fuel injection, ignition, YCC-I and YCC-T. Finding the maps and deciphering the programming is not an easy task.
How It’s Done
As you might imagine, it’s a difficult thing to send your ECU off in the mail along with $449, and get in return what looks like the exact same thing. But while the actual reflashing of your stock ECU may take only a few minutes, many changes are made and it requires a huge effort to get to the point of actually making those changes.
Inside the Yamaha R1 ECU are three CPUs (Central Processing Units), each essentially a tiny computer complete with memory. One CPU manages only the YCC-T ride-by-wire throttle, while another looks after everything else: injection, ignition, the YCC-I two-position intake stacks and all other operations. The third CPU oversees the other two, making sure everything works properly and ensuring that the YCC-T doesn’t malfunction. Because Yamaha, along with most other manufacturers, does not disclose the exact internals of the ECU or the CPUs’ programming, the ECU must be hacked in order to find the maps—a lengthy process. First, the ECU is cut open and the circuit board potting—a coating that protects the internals but also covers and hides everything—removed. This reveals the circuitry and components, and from here a way into the CPUs can be found. The R1 ECU, for example, allows access through debugging ports that are wired to its external connectors. Other ECUs, however, may require a different avenue or even additional wires soldered directly onto the board.
Once the CPUs are accessed, the internal memory containing coding and data can be downloaded to a computer and examined. But rather than an obvious program and maps, the output is simply a vast array of numbers that must be deciphered. There is software available that helps with this decoding, but it’s still a lot like looking for particular clumps of hay in a haystack. Even once a map or bit of software is discovered, some detective work is required to find what each does—for example, a piece of coding that points to what looks like a map may also point to a port on the CPU; that port may in turn be connected to a pin on the ECU’s connector that routes to the throttle position sensor, indicating the map relates to the TPS. As you can imagine, the entire process can become very involved and lengthy. Beau Braunberger, who looks after this code work for ECUnleashed, revealed that the R1’s ECU contains 80 maps in the YCC-T CPU and another 230 in the EFI CPU. These maps cover everything from the crucial injection and ignition functions for each cylinder to mundane operations such as the AIS valve. The R1 has every map duplicated; in U.S. bikes these maps are identical, but in Japanese bikes, for example, one complete set of maps is unrestricted while the other is the 100-horsepower restricted version.
With access to all the maps as well as the programming and even whatever unused parameters may be available, some interesting modifications can be considered. ECUnleashed is working on a quickshifter using the stock ECU, while Braunberger’s personal R1 is set up with cruise control, all through the stock ECU. The possibilities for tinkering are almost endless, especially with as powerful an ECU as the Yamaha has. The Yamaha’s ECU is made by Hitachi and the two main CPUs inside are made by Renesas—a company owned by NEC, Hitachi and Mitsubishi. Similar CPUs can be found in various Suzuki and Kawasaki models, meaning most can be dissected and reflashed in a similar manner. Honda ECUs, however, are made by Keihin; Braunberger calls them throwaway ECUs as there is no easy way to access the internals to pull out the coding and maps—that’s not to say it can’t be done at some point, however. Interestingly ECUnleashed closes any access to the ECUs it reflashes, meaning the changes made by the company cannot in turn be extracted.
Sportbikes may be a few years behind the automobile world in this area of performance modifications, but companies like ECUnleashed are rapidly making progress. Expect this to be a more common modification in the years to come—provided the manufacturers continue to allow some form of access and/or innovative programmers continue to work their magic. SR