Replacing the exhaust system is one of the most popular customization options for motorcycles. Every rider has his or her own criteria for choosing an aftermarket exhaust system, such as sound, power feeling, style, etc., but everyone says, "I love it!" "It feels great!" and the SP TADAO Power Box is the one they all agree on. What makes it feel so good! let me introduce the philosophy of manufacturing and my reviews of the exhaust system!
Do you want maximum power output on spec or practical performance on the street?
Compared to the OEM exhaust system, the silencer end overwhelmingly outperforms the OEM exhaust system in terms of lightness. While the silencer body is a simple cylindrical shape, it has passed proximity noise and acceleration noise tests and obtained government certification.
The OEM exhaust system developed by motorcycle manufacturers over a long period of time have a high degree of perfection and provide performance that is not excessive in any situation. On top of that, aftermarket parts constructors develop exhaust systems from various perspectives in order to create exhaust systems that are chosen by users.
From the user's point of view, it is natural that the user would want to increase the maximum power output if he/she is going to go to the trouble of customizing the exhaust system. However, if you think about it calmly, how many opportunities do you have to pull the engine rpm close to the red zone in daily use, such as city driving or touring? It may be true that it is no use worrying about such things in customization, but it may be easier for the rider to understand that replacing tires with higher grip or installing brakes that improve braking feel is better than an exhaust system that pursues peak power.
For SP TADAO, which has been developing exhaust systems for the past 40 years, a major issue was what kind of character to give to its own brand of the exhaust system. The company has long been creating characteristics that generate significant torque from 5,000 to 6,000 rpm while achieving peak power that exceeds that of the OEM exhaust system.
However, when it became apparent that many city and touring riders regularly use a lower rpm, specifically around 2000 to 3000 rpm for a 1000 cc class big motorcycle, the development policy was drastically changed.
The current SP TADAO exhaust system, named "Power Box," has been developed so that the driver can feel the thickness of torque from about 2000 to 3000 rpm with the clutch connected and the throttle slightly opened, although it varies depending on the displacement and model. The rich torque from low rpm may be mistaken for a low-speed type, but this is not the case. While focusing on increasing torque at low rpm, the aftermarket exhaust system also achieves a maximum output that exceeds the OEM exhaust system.
With these characteristics built in, many riders can feel the motorcycle powerfully moving forward as soon as they engage the clutch with the transmission in first gear, when they open the throttle at an intersection, or when they accelerate to pass a vehicle on a two-lane road.
There is no need to open the throttle wide and wait for the engine rpm to rise; instead, the characteristics are built-in so that magnificent torque comes out from anywhere in response to the amount of throttle opening.
SP TADAO aims to achieve both comfort and exhilaration without tiring the rider, both in town and on touring trips. This is the keyword that SP TADAO uses to express this.
POWERBOX FULL, even with a 250cc 4-cylinder, you can feel the torque increase from 4000rpm.
This high-revving engine produces a maximum output of 33 kw (45 PS) at 15,500 rpm and a maximum torque of 21 N-m (2.1 kgf-m) at 13,000 rpm, but the power box full allows the driver to feel a boost of torque from 4000 rpm. SP TADAO's style of exhaust system development is to repeat prototyping to create transient characteristics rather than peak power.
The OEM exhaust system for the Ninja ZX-25R is a one-piece unit from the exhaust pipe to the silencer, so the power box was developed with a full exhaust system. The bypass pipe, the layout of the assembly, and the length of the main pipe were all tested to ensure that the staff could give their own stamp of approval. The staff themselves were able to give their own stamp of approval.
The inside of the silencer has been uniquely designed to meet the latest trend of reducing the overall length of the exhaust system while providing torque characteristics that exceed that of the OEM exhaust system and still meet noise regulation values.
SP TADAO's Power Box series includes four types: the "Power Box" slip-on silencer type, the "Power Box Pipe" which replaces only the exhaust pipe, the "Pure Sport" for scooters, and the "Power Box Full" which replaces the entire exhaust system; here is a review report on the Power Box Full for the Kawasaki Ninja ZX-25R.
During the racer replica boom of the 1980s, all four Japanese manufacturers sold 250cc four-cylinder models, but today the 250cc class is dominated by two-cylinder models.
Kawasaki's Ninja 250 with a two-cylinder engine is also popular, but the Ninja ZX-25R has been the talk of the town for quite some time because of its newly designed four-cylinder engine. Unlike in the 1980s, when the intake system was carbureted, the ZX-25R's engine, now fuel-injected and precisely controlled, has a sense of power from low speeds and is quite practical around town.
Since the OEM exhaust system is a one-piece type that integrates from the exhaust pipe to the silencer end, the power box developed by SP TADAO is also a full exhaust type. Even if the engine character is high-revving type, it is essential for the power box to pursue torque in the low and mid-speed range that is frequently used in town, and the secret of rich low-speed torque is hidden in the short type design.
The OEM exhaust system has a large expansion chamber in front of the silencer, where torque and power are balanced. In contrast, the ZX-25R Power Box Full has a cylindrical silencer laid out at an angle under the swingarm, but the pipe layout is simple and the overall length is short. Such exhaust systems tend to have high-rpm, high-output characteristics, especially on models with smaller displacements.
In lower gears, the engine blows up quickly, but it is not possible to maintain high rpm when driving in the flow of other vehicles on public roads. Also, at low speeds, if the engine is revved up in lower gears, the throttle will be over-sensitive and the exhaust noise will be bothersome. However, if you upshift early, the engine speed will drop, but the torque is thin and tends to be rough. This is the weak point of the 250cc class.
Test riding the ZX-25R with such preconceptions will give you a completely different impression. The ZX-25R's sporty presentation is appealing, with the tachometer displaying numbers at 4000 rpm and above, but from that 4000 rpm, the torque is much thicker than OEM.
It would be an exaggeration to say that it is on par with the 400cc class, but the torque from 4000 to 8000 rpm far exceeds that of the 250cc class. However, if we calmly judge how many of those situations actually exist, the added torque at 4000 rpm and above will give the rider a "good feeling! The torque added above 4000 rpm will make the rider feel "good" in the city.
Even though the torque band has been widened to the lower rpm side, it does not spoil the good extension of the 4-cylinder that performs up to 17,000 rpm in a straight line. Although it is not easy to bring out the full potential of this exhaust system on the highway as well as in the city, one can get a glimpse of its ability to achieve maximum power output that exceeds that of the factory unit.
The torque characteristics provide a comfortable driving feel without the need to keep the engine revving at high rpm, and the exhilarating feeling that rises as the engine rpm increases. SP TADAO's pursuit of "Good Feeling" is fully incorporated into the Ninja ZX-25R power box.
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