In 2010 Contrast started an extensive R&D program devoted to the large scale in which one of the objectives was this engine we introduce you
The Dragon engine was born from a long time experience, thoroughly working and analyzing the Zenoah engine. We chose taking every single part of a 23cc engine and improve them to the maximum having our mind in the races, but without leaving apart the regular things used in large scale. Counting on the design in the thermodynamic area of Quim Padro (QM) and his OEME engineering office, we designed a smaller engine, solid and modern, with the best of Zenoah –its lightness and ruggedness- and with the best of the modern competition 2T engines, without forgetting some very advanced details in electronic. The result is a powerful engine, very powerful, the most powerful of all by far over the usual engines in large scale. With a very advanced electronic and with five different registered ignition curves so that you choose the most appropriate one at every moment of the competition. With a pack of cylinder, cylinder head and piston designed to make the most of each drop of petrol and allow a thousand geometries and compression level, and with several advantages we detail below which no one else is able to offer to you.

Here we detail the main characteristics of the motor Dragon QM23:

·         Relationship of diameter and  run of 32 mm x 28,5 mm
·         Extreme cubic capacity of 22,92 cc
·         Cylinder with a separated head in order to be able to adjust the compression
·         Three models of different cylinder heads to choose
·         Technical coating of the inside of the cylinder made of Nikasil
·         Big size exhaust port with central column
·         Cylinder fixed to the crankcase by four screws
·         Crankcases made on casting of a smaller size
·         Base of the engine placed in the crankcase for a better lining up
·         Fixation pines and coordinated mechanization of each pair of crankcases
·         Our own designed crankshaft, lighter and smaller
·         Bronze friction bearing in the seals of the crankshaft
·         Ultra light connecting rod with silver ball bearing at the base.
·         Electronic of the starting designed to work up to 36.000 rpm
·         5 elegible electronic ignition
·         Super-light fan in plastic with ballasts to choose at every moment the inertia mass you prefer.  
·         External cover in carbon with a big technical coating all over the cylinder and low weight.  
·         Long admission collector and Walbro WT613 carburettor.

SPLIT CYLINDER AND HEAD First of all, it has to be said that this system of cylinder and separated head meets all the EFRA and IFMAR rules of the category. This system offers several advantages with regards to the cylinder and cylinder head in just one piece. We can lift or lower the cylinder and its transfers with thicker or thinner cylinder gaskets without affecting the squish compression and height that may be regulated in an independent way. It allows us more options of preparation by using different cylinder heads and levels of compression. With an open cylinder we can use the internal treatment of Nikasil, much harder and more resistant than the chroming of the Zenoah cylinder. With this system in two pieces we facilitate the cleaning, maintenance and tuning of the different internal parts of the engine.
THE CYLINDER, A JEWEL The cylinder is the heart of a 2T engine. Our cylinder designed by Quim Padró shows several details based on his experience about motorcycles, karts and large scale for 50 years. We start from a solid base with four screws in order to avoid loss of shape and breaks so well-known in engines of only two screws. The admission port has got a big opening to allow a big loas of mixture of the crankcase especially at high rpm. The side transfers are asymmetrical both in shape and height and thanks to their design they increase the speed of gases mixture. The exhaust port has been deeply analyzed searching for the maximum opening and breathing at high revolutions, that’s why we have chosen a system of central column which gives more safety and it perfectly guides the piston at more than 20.000 rpm.
THE CRANKCASE, THE BEST BASE Making a good crankcase is not easy, it is the element that holds and joins the engine to the car and because of that it has to be solid but light at the same time, easy to work with and with a precision of hundredth parts in order to achieve the better turning of the crankshaft. Our crankcase meets all that and much more. It has been designed for a simple assembling and disassembling because it has the screws visible on its left side; it also has all the regular fixation points that make the engine compatible with all the cars in the market, either with a horizontal or vertical assembling. Unlike the Zenoah the fixation points are in the crankcase and not in the side cover which allows reaching the fan and rotor without taking the engine out of the car. Finally, the inside of the crankcase and its rotation points have been mechanized using the minimum tolerances for a perfect adjustment and to achieve the maximum ease of spin.
THE CRACKSHAFT IS PLENTY OF DETAILS Each part of the engine makes its contribution to the final performances and the crankshaft of the Dragon engine provides a very important part because it’s full of improvements and details. The first one is its smaller diameter, which also allows having a very small and light crankcase. The second detail is its shape that pushes and accelerates the mixture towards the side transfers, opening thus a big hole in the base of the cylinder just in the moment of spinning. The third detail is the position of the connecting rod base that allows us to increase speed and achieve the maximum of the allowed cubic capacity. And the last improvement is the use of a silver ball bearing at the base of the connecting rod, a quality detail only used by the best tuning engines of the market.
THE ELECTRONICS MAKE THE DIFFERENCE We are in the electronic era and an engine that easily spins at more than 20,000 rpm needs the best ignition control with all the help of modern electronic. We use a rotor system and a very strong ignition pickup that guarantee the lack of problems in that sensible point. The signal of the rotor is processed by a printed circuit specifically designed for this engine with elements that easily work up to 36.000 rpm, which guarantees us a high ignition intensity at the right moment up to 600 times per second. But the final detail is the capacity of this starting of recording, selecting and reproducing different ignition curves according to the driver’s taste by means of a selector. The Dragon engine is delivered with five pre-programmed curves:
• Curve 1 booster.- Maximum power in all the revolution range, for those moments in which you need everything no matter the consumption, as the clasificatory heads or low-consumption tracks.
• Curve 2.- Reduced consumption. A curve that highly reduces the consumption affecting only in a light way the available power, ideal for finals in tracks with a high consumption of petrol.
• Curve 3.- Low-power and low-consumption curve, ideal for rainy days, with low level of track grip or to use in all tacks where an easy power is needed.
• Curve 4.- It improves the low rpm. It increases power at low and mid rpm, by noticeably reducing power at high rpm
• Curve 5.- It improves in hi rpm. It increases the power and regimen of the engine at mid and high rpm, by noticeably reducing the power in low rpm.
The curves 4 and 5 are ideal to combine with different ballasts in the flywheel.
THE OTHER DETAILS A priority objective when designing this engine was keeping a low weight similar to the Zenoah’s that will not interfere in the chassis performance. This has been one of the greatest achievements of this engine, to increase the strength and benefits of the present-day engines keeping the same weight.
The refrigeration is important when you increase the efficiency and power, more power means more heat and bigger refrigeration necessities, our new fan with blades at both sides and the big openings of the carter allow that increase of air flow needed. The carbon cover completely closes the engine in the three sides, including the pipe, and guiding the flow towards its exit through all the cylinder and cylinder head.
Conic intake Venturi. Our filter base incorporates a Venturi cone that extends the Venturi of the carburettor increasing the speed of the admission air and facilitating breathing at high speed and the acceleration speed.