Why Use a Supercharger?
-by Richard Albans
TTS Performance Parts Ltd are at the forefront of development for supercharging modern motorcycle engines and with ROTREX's help are forging ahead to develop high power conversions for a large range of models. Please contact TTS for all your performance needs.
ROTREX superchargers are not positive displacement but work on the principle of a turbine, the same way that turbochargers operate. In order for this principle to work the turbine has to spin at very high speed. In turbochargers the hot exhaust gases spin the turbine up to speeds of up to 150,000RPM. TTS/ROTREX superchargers spin up to 250,000 rpm depending on model. To get these high speeds in the TTS/ROTREX supercharger the input drive shaft operates through a special planetary gearbox to speed up the turbine, the result being high-pressure air out of a compact unit the size of an alternator.
The gearbox is a fixed ratio traction roller transmission, which has a built in capability to adjust contact forces applied to the traction surfaces of the transmission in relation to the force required. Traction roller transmissions require relatively large engagement forces between their traction surfaces to prevent slippage.
The TTS/ROTREX unit automatically adjusts the contact force, to optimise the gear for those applications where the transmission transmits less torque, the amount of frictional losses and wear is reduced. Where full torque is transmitted, the transmission has the capability to provide sufficient traction force to prevent slippage.
The TTS/ROTREX charger being of this turbine type overcomes the drawbacks of previous superchargers, these problems being the main reason car manufacturers started to develop turbo chargers some 20 years ago and only now are manufacturers coming back to look at superchargers.
The benefits of the TTS/ROTREX charger over other superchargers are firstly being centrifugal they take little power to drive and so save BHP that would otherwise be lost in driving the unit. Another benefit to using the TTS/ROTREX, as opposed to any displacement charger is the fact all displacement chargers produce maximum boost at about 3000 engine rpm and then tail off as you rev higher. This is a big problem when driving, as you do not want near max power at low rpm as you get tremendous traction problems, which is a particular problem if you compete in drag races and standing quarter miles, as all you do is spin the wheels and go nowhere. The TTS/ROTREX, being a centrifugal type charger has a nice even increase in boost pressure rising in a linear pattern, with useable extra power from 1000 engine rpm and max boost at say 11000 rpm (or at what ever you desire, depending on the engine).
The latest revision of TTS/ROTREX unit is integrated with it's own oil pump and supply of special traction fluid. This gives extremely good reliability.
The TTS/ROTREX supercharger conversion offers huge advantages over a turbocharger:
> Total drivability: - what you do with the throttle is transmitted directly to the rear wheel.
> No throttle lag: - instant throttle response.
> No huge surge in power: - power is progressive, increasing right to the redline.
> Reduced peak cylinder pressures: - as torque is spread over a large range of rpm with no sudden increase, peak torque is lower but more useable.
> Reduced strain on engine components: - with the increased useable rev range and progressive torque increase engine components are not subject to massive changes in cylinder pressure associated with turbo installations.
> Efficiency is higher: - as there is no heat build up within the supercharger the input air temperature is significantly reduced over a turbocharger, reducing detonation and increasing power output and efficiency. A typical turbocharger has an efficiency of 65% a TTS/ROTREX is 72%.
> Exhaust temperatures reduced: - unlike turbo's there is no excessive back pressure and heat build up within the engine and engine bay. This keeps engine components within their design perimeters and reduces fatigue in components like exhaust valves, seats and springs and reduces water and oil temperature.
> Safety: - In race applications, engine components are pushed to and beyond their limits. In the event of an engine disintegrating the destroyed components ejected out of the exhaust do not go through the supercharger. On a turbocharger the exhaust impeller would be destroyed requiring a total turbo rebuild.
> Reduced replacement time: - If the supercharger was to break (highly unlikely) then a new one could be fitted in less than 10 minutes.
The TTS/ROTREX supercharger conversion offers huge advantages over normally aspirated:
> More horsepower: - normally aspirated engines will never make as much power as a well developed ROTREX supercharged engine.
> Less cost: - the TTS/ROTREX supercharged engine will cost less per BHP than NA engines.
> Less fussy: - the TTS/ROTREX supercharged engine drives much more smoothly with no defined power band unlike a highly tuned NA engine.
> Easier starting: - with the same or less compression than an NA engine there is no extra strain on the starter motor or starter gear train. Lower maintenance: - Without wild cams and stronger valve springs the valve gear gets an easier time and the cam chain and tensioners last longer.
> Less fatigue: - as the boost damps the pistons inertia during the valve overlap period there is less stretch on connecting rods. As power is progressive there is no unnecessary stress on any engine component as the full rev range can be used.
The engine does not have to be made larger to produce the power, so there is no need to replace with pistons of larger diameter or the cost of reboring or replating. Combining the TTS/ROTREX supercharger conversion with normally aspirated tuning. We have found that wilder camshafts can be used to an advantage with the supercharged engine. Increasing the engines capacity can also produce extra gains in performance.
Anything to increase the strength of you engine is always worth while. Combining the TTS/ROTREX supercharger conversion with nitrous oxide injection. Introducing nitrous oxide into the supercharged engine has the effect of cooling the intake charge temperature, reducing the effect of knocking and at the same time increasing BHP. An excellent combination.
TTS Supercharger conversions are available for Suzuki Hayabusa. Suzuki GSXR1000. Suzuki GSX1400*. Kawasaki ZX12*, Z1000*, ZX10R*. Honda CBR1100*, CBR900*. Yamaha R1*. Buell*. Triumph Speed Triple*. Others under consideration.
For further information on increasing your motorcycle engines performance using a TTS/ROTREX supercharger please contact us.