This is the Ultimate Engines M-8 tuned combo.
The Ultimate Engines M-8 is a .21 (3.9cc), long stroke, 8 port engine with a tuned crankshaft. It is designed for drivers who compete (or want to compete) at the highest level and are looking for a powerful and linear engine with good power at both low and high R.P.M. Its configuration essentially gives you two engines in one; with a soft clutch you will have a smooth and very linear engine, but with a hard clutch you will have a very aggressive engine.
It features an over sized cooling head to improve performance at high temperatures. The R7 connecting rod made from super light aluminum and designed to create the least amount of turbulence inside the engine. The sleeve has 5 transfer ports to create a linear power output while keeping fuel consumption low. The tuned crankshaft is manufactured with a large bore intake and has a special shape to optimize flow of the fuel mixture in the engine.
The rear bearing has an outer diameter of 25.8mm. A large diameter bearing is used in order to avoid ring distortion and to increase the lifespan of the bearing. The two needle, slide valve carburetor features a standard design that allows the use of interchangeable venturis to tune for any track condition.
The cooling head for the M-5 is new for 2015. The Modelix team specifically went with an oversized head to help keep the engine running cooler and improve performance when running at higher temperatures. Although it is oversized, it’s drilled and milled to make it light and to keep the overall center of gravity of the engine low.
Another change from the previous design is the diameter of the central hole of the head where the glow plug fits is reduced. For those that use temperature guns to measure engine temperature this will give you a more accurate reading because the gun will not factor the temperature of the plug in with the overall engine temperature since the plug is not easy to “see.”
Another improvement for 2015 is the use of a double sealed front bearing. This will help keep dust out of the engine and will make the engine easier to tune and allow it to better hold the tune.
The combo includes:
Engine: M-8 .21 Tuned Competition Engine
3 venturis: 6.5mm, 7.0mm & 7.5mm
Exhaust System: Ultimate EFRA 2119 pipe plus manifold w/Masterfix system
Clutch - Ultimate Racing COMPAK clutch system with aluminium shoes and 1 mm springs (UR0620-XA)
Clutch Bell – Ultimate Racing 13T ventilated clutch bell with Ultimate Racing bearings
Air Filter- Ultimate Racing air filter case with pre-oiled foam