Technique and elaborations Thu 23 November 2017

POWER CDI I can remap your motorcycle

A person I hold in very high regard for his technical knowledge in this area is Stefano Spagnul.
For years he told me about a mysterious remappable power pack he was testing with the help of a friend. Lately, every time we met and during our phone calls, we inevitably talked about the developments and results he was achieving.
“As soon as you have the chance I will let you try it!”
The opportunity presented itself when the new project Discovery Endual was launched and, without losing too much time, we scheduled the test. Stefano came at our meeting with no less than two motorbikes, a KTM 300 2t and a TM 300 2t, both made in 2017.
I was not really convinced this POWER CDI power pack could offer real benefits – I do not do well with electronics and I believe enduro is a sport where you have to adapt your way of riding to the terrain you are on - so I was averse to this technology at the thought of passing hours in front of the computer, trying to find the best engine contribution to a specific situation. On the other hand, the possibility of having a device that made the bike easier to handle and that granted even a small advantage over the friends with whom I usually share my Sunday trips, aroused curiosity as well as my ego.
Stefano started illustrating the technical features of the power pack and as details on itssophisticated functions came pouring, I became increasingly disheartened. Would I ever be able to take advantage of its benefits?
With this aftermarket power pack, the user can map the engine on his own, using real-timetelemetry, DPC (Dynamic Power Control) and many other functions unseen in any other CDI on the market. The DPC is an innovative system capable of modulating the ignition timing in real time, and, in this way, of actively controlling the engine output as a precise function of the throttle; in other words, the result is a powerful and reactive engine easy to handle. We will try to better explain the power pack potential using practical examples.
How many riders are able to take full advantage of the total horsepower output of their bike? How many of us return home exhausted after a ride because the bike gave us a hard time more than once?
Just think of all the sudden accelerations, the accidental slips, the strain in taming a motorcycle that tends to rear up continuously because we are not able to get all the power down!
How many times did we, owners of a two-stroke engine, ask our mechanic to make the bike less aggressive and more electric?

The most common solutions are: reducing the compression ratio and/or increasing the squish clearance, weighting the flywheel, choking the exhaust or richening the fuel mixture. Targeted mechanical interventions are used to enhance or accentuate some characteristics of the engine, but they are always a compromise that therefore cancel or deaden other characteristics.
In our examples, the motorbike certainly becomes more manageable, but the engine tends to lose power and response that could be useful when dealing with obstacles or steep climbs.
The Power CDI power pack with the Dynamic Power Control seems to be the solution. In fact, it can instantly modulate the engine output by acting on the ignition timing, and making very wide correction at each single round of the engine: the engine response becomes much more manageable and foreseeable as a function of throttle opening.
A practical example will help to better understand the effectiveness of the device. If you go from dry to slippery ground, keeping the throttle in a constant position, the engine rpm may increase causing the wheel to slip, sometimes with disastrous consequences. On the contrary, if the rider abruptly opens the throttle to drift or wheelie to jump and obstacle, the power pack recognizes that the rider is requiring power and does not intervene to oppose the action.
In short, it is like going from an ultrasoft map to an ultrahard one, based only on how you manage the throttle and adding a new dimension: the speed with which one opens the throttle not only the quantity. The system is intuitive in use: on slippery ground, it is natural to open the throttle only slightly and slowly while, on ground with a lot of grip, it is natural to rapidly and aggressively open the throttle.

What to do to install the Power CDI?
Besides replacing the original power pack, the motorbike must have a carburetor with TPS (throttle Position Sensor), if not already installed. Some bikes, like the Yamaha YZ 250 or the Beta 2017 (the Racing too) already have the TPS but on other models the carburetor must be replaced with one that has the TPS. The power pack also works on the original carburetor without TPS but only with the latter all the advanced functions are enabled, such as the Dynamic Power Control, the pipe-bangprevention (that eliminates the annoying “deceleration surges”), the anti-stall, etc.

Our impressions
The TM 300 is known for having a big engine that pushes hard upward while downward and pickup are not its strong points. With the power pack, it’s like riding a 4-stroke 450, the bike has more pickup, its rpm increase gradually and it never becomes difficult.
On the dirt track used for the test, we easily rode in third gear, exiting the curve, with the typical rumbling sound that characterizes the propeller of this motorcycle manufacturer, we were pulled towards the next curve. But it’s riding in the woods that you better appreciate the benefits of the power pack; the output is more fluid which allows you to fully enjoy the properties of this bike.
To describe how the KTM behaved, I think I only need to tell the following anecdote. Only at the end of the test did Stefano disclose that the bike we tested was not a 300 but a 250cc.: we were astounded! To only think that when I exchanged impressions with some people present during the test I told them that I was particularly satisfied by the improvements this power pack gave to an engine that already was a reference!
Also significant is the fact that the Power CDI can be adapted to any type of 2-stroke or 4-stroke bike, therefore if I wanted to change brand, displacement or switch from a gas engine to a mix fuel engine or an injection engine, it would be no problem I would only need to request the files for the update and the deal is done.
The DPC function is the true strong point of this device, the sophisticated system that allows you to take advantage of the full power of the engine managing it directly from the throttle so that the response of the engine is the desired one on any type of terrain. It is the opposite of what is normally offered, i.e. to have the possibility of changing maps to adapt the response of the engine to the terrain (the conventional sun/rain button); here electronics intervene on the throttle opening without altering or limiting power. Awesome!
PowerCDI will soon be available even for the TPI (transfer port injection), with Bluetooth module and software supplied as standard; riders will be able to freely tune their bike according to their taste even in the middle of nowhere, and they will also enjoy a considerable improvement of the engine performance, especially at low or medium rpm, and obviously the DPC, the pipe-bang prevention and all the other features already available on motorcycles with carburetor.

For more information or purchasing this power pack: www.powercdi.com

Text and tester: Pietro Bartolomei