Introducing the Sea-Doo 4-TEC SUPERCHARGED 185HP & MASSIVE TORQUE iame41-1.doc 29Mar03 Page 1 of 2
Another Sea-Doo watercraft first and only. Introducing the 185hp, GTX 4-TEC SUPERCHARGED PWC. The 4-TEC Supercharged engine is the industry's first and only supercharged watercraft. This year, the 4-TEC Supercharged is available in two models: GTX 4-TEC Supercharged GTX 4-TEC Limited Supercharged 185hp: 30 more horsepower than the normally aspirated 4-TEC engine. Zero lag: The supercharger is always spinning, for instant throttle response. The 4-TEC Supercharged is not only in a class of its own, it is starting a new school. iame41-1.doc 29Mar03 Page 2 of 2
Differences between the 4-TEC Supercharged and the 4-TEC normally aspirated. The new 4-TEC Supercharged and the 4-TEC naturally aspirated introduced in 2002 share many components. The Supercharged engine is mounted in the same new GTX hull that was introduced last year for the 4 TEC naturally aspirated. Both exteriors may look similar, except for color, decals & etc., but the main differences are located under the seat. Supercharged Naturally Aspirated Engine - Rotax Marine 3 cylinder, 4 valves per cyl. Rotax Marine 3 cylinder, 4 valves per cyl. Bore - Stroke - Capacity Fuel system - Injectors 100 mm 63.4 mm 1493 cc Sequential EFI Bosch 100 mm 63.4 mm 1493 cc Sequential EFI Siemens Comp. Ratio 10.5 to 1 8.1 to 1 Ignition System Denso Inductive, Coil on plug Denso Inductive, Coil on plug RPM limit - 7750 7650 Max Power 185 HP (138 kw) 155 HP (115 kw) SUPERCHARGER iame41-2.doc 29Mar03 Page 1 of 2
Air Intake and Exhaust Systems The GTX 4-TEC Supercharged has specially designed intake and exhaust systems to ensure a very quiet high performance water craft. D-SEA-BEL sound reduction system: The GTX 4-TEC Supercharged is equipped with a modified version of to the Sea-Doo D- SEA-Bel sound reduction system that allows sound waves to cancel each other out. Helmholtz resonators are strategically placed in the exhaust system, along with 2 large water cooled mufflers, Large Mufflers EXHAUST MANIFOLD These are some of the new resonators iame41-2.doc 29Mar03 Page 2 of 2
Air Inlet Cover Voltage Regulator Airbox Air duct to supercharger A new air box and air inlet duct are used in the Sea-Doo 4-TEC Supercharged. The air box dampens sound emissions and also ensures the air intake is high above the bilge. Internal defectors remove any air borne water droplets and one way drains get rid of any water collected in the air duct. The alternator voltage regular is also attached to the air box, using the intake air stream for cooling. The intake manifold is a reinforced plastic type with equal length runners, a ventral plenum chamber and an internal, metal mesh flame arrestor. iame41-3.doc 29Mar03 Page 1 of 1
Throttle Body The fresh air from the air silencer box is routed to inlet of the supercharger. From there pressure is increased to a maximum of 0.35Bars (5 psi). The throttle body is located at the rear of the intake manifold, next to the supercharger. On the 4-TEC normally aspirated, it is located at the front of the intake manifold. The same throttle body is used as on the 4- TEC normally aspirated version: a 52mm Dellorto. Important: Never attempt to adjust the butterfly opening; it is factory adjusted and sealed. It does not require any adjustment. Idle speed is electronically controlled.
Supercharger We know that every engine needs air to ensure proper combustion of the fuel. On naturally aspirated engines, air is dra wn in by the low pressure created by the downward movement of the piston in the cylinder. At idle, when the throttle is snapped open the air has plenty of time to get into the cylinder. But when the engine is at high RPM, the time available for the air to get into the cylinder is greatly reduced. This consequently reduces the volumetric efficiency of an engine. In order to reduce that loss of volumetric efficiency, we use a supercharger. With a supercharger, the air is forced into the intake system instead of being drawn into it. By using a forced induction system, an engine can produce much more power than a naturally aspirated version of the same displacement. In order to maintain the proper air fuel ratio, the fuel system must also deliver more fuel. The greater the air/fuel mixture an engine can burn the more power it can produce. The supercharger is mechanically driven by the crankshaft using a ring gear on the flywheel to drive a pinion on the supercharger shaft. In the 4-TEC Supercharged we use a centrifugal type supercharger because it is light, compact and very efficient. The centrifugal effect of the spinning impeller is that the air is accelerated along the length of the blades from the center to the outer edge, raising it s pressure. The supercharger is mechanically driven by the crankshaft. iame41-4.doc 25Mar03 Page 2 of 8
The rotational speed of a centrifugal supercharger is 5 times the engine RPM. On the Sea- Doo 4-TEC Supercharged, we use this type of supercharger because its sound level is very low and it is a very compact size. Another reason to go with a supercharger and not with any other forced induction device is because of the RPM constant fluctuations on a personal watercraft engine. The impeller is driven mechanically by the crankshaft so when hitting the throttle, all you get is crisp and aggressive response no lag! Supercharger Slip Clutch The impeller of the supercharger still has a certain amount of inertia and is submitted to sudden RPM fluctuations when the watercraft jumps over the waves. SLIP CLUTCH The engine speeds up when it's out of water and drops rapidly when it gets back in the water. The inertia of the impeller coupled to this rapid change of RPM could apply enough torque to the shaft to break it. To prevent this, a slip clutch is fitted between the gear and the shaft of the supercharger. It absorbs the momentum of the impeller when the RPM drops rapidly. The clutch uses 5 wave springs washers as a to provide the necessary friction force to the slip clutch, to minimized the effect of RPM fluctuation on the supercharger. Spring washers iame41-4.doc 25Mar03 Page 3 of 8
4-TEC Supercharged Engine The normally aspirated and the Supercharged 4-TEC engines share many components. One component that is different on the supercharged model is the PTO or flywheel cover. The supercharger is mounted on this cover and It has an added oil passage and a spray nozzle for supercharger gear lubrication. The centrifugal type supercharger features Lightweight, simple construction, no high temperature sections. Easy maintenance Takes up very little space Suffers no throttle lag Only one turbine is required Relatively low rpm (< 40,000) iame41-4.doc 25Mar03 Page 4 of 8
The supercharged model camshaft is different from the naturally aspirated 4-TEC by having less overlap in the valve timing. A new one piece valve guide seal combining the valve spring shim and the seal is used. It will not retrofit to previous model years, because it uses a different cylinder head machining. The compression ratio is: 8.1 to 1. The crankshaft has a new heat treatment to improve strength. This is the same part used in the normally aspirated 4-TEC engine version. Pressure lubricated plain bearings are used on both the crankshaft and the counter rotating balance shaft. The lubrication system is dry sump with the oil tank contained in a separate cavity in the crankcase casting. Each cylinder s crankcase is separate from it s neighbors allowing each piston downstroke to blow the oil back into the oil tank, through passageways in the crankcase. A scavenge pump driven from the balance shaft returns oil in remaining areas back to the oil tank. iame41-4.doc 25Mar03 Page 5 of 8
The 4-TEC Supercharged uses a different MAP sensor to read both intake manifold pressure and vacuum. The fuel injectors are from Siemens. They share the same connectors with the Bosch used on the 4-TEC normally aspirated. The center injector connector is gray for easier identification. The Electronic module (MPEM Multi Purpose Electronic Module) and the engine management system ECU are recalibrated and not interchangeable with the 4-TEC naturally aspirated. The BUDS (Bombardier Utility and Diagnostic System) version G2.0.0 or higher is required to program keys and communicate with the ECU and MPEM. Rev Limiter and Learning Key The learning key function as well as the rev limiting function is accomplished by shutting off the fuel injection to a cylinder. Each time the RPM limit is reached, whether in the learning key or normal rev limiting function, the cylinder ready to fire next will be shut down. More cylinders will cease to fire until engine speed falls below the rpm threshold. Once engine speed is below the threshold, the next cylinder is allowed to fire... until engine speed goes above the threshold -repeat, repeat, repeat. Regular Key: engine speed limit is 7750 RPM's. Learning key: one cylinder is gradually shut down starting at 4300 RPM's. At wide open throttle, the end result is one cylinder continuously shut down which limits RPM's to around 5000 RPM on a stock impeller at sea level (lower rpm at altitude). The cylinder to be shutdown is randomly selected to share the load. The Learning Key function is provided by using a lanyard key containing a different electronic chip to the normal key. The MPEM recognises the type of lanyard as soon as it is installed and applies the appropriate rpm limit. The Learning Key allows novice riders to become familiar with a high performance Sea-Doo with little risk of danger. iame41-4.doc 25Mar03 Page 6 of 8
Cooling System The 4-TEC Supercharged uses the same cooling system as the standard 1503 4-TEC.: Expansion tank An environmental friendly closed loop system for the engine, using the ride plate as a heat exchanger (radiator) and a more conventional open loop circuit for cooling the exhaust. Water pump and thermostat Ride plate The exhaust Goose Neck is a double walled, water cooled, stainless steel fabrication that connects the exhaust manifold to the first muffler. The exhaust is dry until it exits the goose neck. The inside material of the exhaust goose neck is different from the 4-TEC naturally aspirated. It is calibrated to endure the different operating temperature of the 4-TEC Supercharged. The 4-TEC Supercharged model comes with a red round sticker on it for easier identification. iame41-4.doc 25Mar03 Page 7 of 8
The 4-TEC Supercharged uses the same jet pump as the 4-TEC naturally aspirated with these exceptions: To match the calibration of the supercharged engine, the venturi has a smaller size: 4-TEC normally aspirated engine: 84mm 4-TEC Supercharged engine: 83mm The impeller is also a different pitch. It uses a specially calibrated impeller to match the extra power of the engine. New support bracket The wear ring is also new. It is longer and has a special construction. This new version will not fit on previous model year nor the 4-TEC naturally aspirated. The jet pump has a side support bracket to ensure the proper pump rigidity. iame41-4.doc 25Mar03 Page 8 of 8