What goes on inside the cases of a stock engine is pretty intense. Violent explosions take place hundreds of times a second, a heavy crankshaft spins 13,000 times a minute, gears slam into place, and clutch plates spin against each other. And it all takes place inside a bath of boiling hot oil.
The incoming air enters the...
The incoming air enters the system through the compressor side of the turbo.
But everything gets much worse in a tuned engine, especially when it's a turbocharged monster. A massive turbo harnesses the "wasted" energy in the exhaust. Then these superheated gasses-essentially an extremely fast stream of exploding flames-are directed onto a small turbine wheel which then spins at 100,000-plus rpm. The other side of the turbo is a compressor wheel that blows more air into the engine to make even bigger bangs. These explosions can triple the stock amount of torque and slam through all the engine components, crucify the transmission, clutch and rear tire.
The Launch (Minus 1 second)
Waiting for the light tree to drop after staging is a lonely place for the rider. Intense concen-tration on the yellow lamps blots out everything; the noise, the heat and the other rider.
But it's pretty intense for the engine too. Our 650 HP Hayabusa motor is a thing of beauty with serious engineering, and it's about to be run to its utmost. We've warmed her up properly (you don't want to be running a thoroughbred like this with cold oil). And at this stage, the motor and turbo are held in a special pre-run condition. The bike is in first gear with the clutch pulled in. The control units: fuel injection ECU, Boost Controller and Anti-Lag System are all primed for a run, so they're running the engine in a pretty weird way. The trick is to have the turbo spinning up to its full speed while the engine is spinning close to peak torque levels. This is where the anti-lag system comes in; the ECU adds extra fuel, and retards the ignition timing, so the fuel is still burning when the exhaust valves open. This sprays a hot, burning, expanding air/fuel mix into the header pipes, which makes the turbo spin up to its boost operating speeds while the engine is only running on a relatively small throttle opening.
The pressure built up by the Garrett GT35 ball-bearing turbo is fed into the plenum chamber, with the excess vented out by a big-bore Tial 46mm external wastegate. At this point, we want about 6psi in the plenum chamber which equates to about 250 HP. Any more and she may flip, and there're no wheelie bars to save us here...
Bang! The green light is lit, and we're already on the move. Letting out the clutch lever is the signal to the engine management systems that we need to go. Instantly, the anti-lag system cuts, and as the throttle plates slam open our turbo is already up to speed, instantly delivering up masses of air at 6psi.
Only for half a second though; the Boost Controller is running a preset timed program of pressure increases, and that initial 6psi boost level is just a gentle intro. It's rough on the clutch though-it's spinning its plates and dumping a load of heat and debris into the oil. But this is no ordinary clutch-it's a heavy-duty lock-up unit that uses weights and RPM to determine its engagement and aid in a smooth launch. Speaking of the tire-it's already distorted by the huge launch forces and is bound to spin some, no matter how smart our boost control or clutch setup might be.
Launch (Plus 0.5 seconds)
The NLR AMS1000 Boost Controller begins to up the boost in the machined billet alloy plenum chamber. A solenoid pressurizes the wastegate on the turbo, increasing the plenum pressure to around 9psi and 300 HP.
The end of first gear is approaching and it's time for a clever shift kit to take over. A pneumatic ram that hammers the lever up in just 70 milliseconds and cuts the ignition a fraction to reduce the load on the gears is ready for action. The anti-lag system kicks in during the shift and keeps the turbo spinning with extra fuel even as the under-cut gear dogs engage and lock.