450 horsepower, from an almost stock-looking Suzuki GSX-R1000. Welcome to the crazy world of forced induction.
For the uninitiated, this is where compressed air is fed into the engine to create astronomical power. Rather than simply relying on the pistons' downstrokes to draw air-fuel mix into the combustion chamber, a forced induction system actively pushes it in.
In this Suzuki GSX-R1000's case, it's achieved with a turbocharger. This uses a turbine, located just after the shortened downpipes and spun by exhaust gases firing out of the engine, to drive a compressor. Compressed air is then fed into the plenum chamber, a sealed box which distributes it between the throttle bodies. Combining this extra air with modifications, like second rail of injectors, to flow extra fuel allows the engine to make more power. Lots of power.
The trick is using the right size turbo. For years people were fitting motorcycles with turbos that were just too small. For example, a 1350cc Hayabusa revving to 11,000rpm will need roughly the same size turbo as a 3500cc car engine, simple because it flows so much more air. If you use a small turbo, which spins up quickly, it'll be monstrous from, say, 3000rpm to 8000rpm, and then tail off – which is exactly what you don't want. You don't want a turbo to boost hard off the line or when you're in a corner. It sounds off, but a big turbo will actually be nice to ride, make more peak power, and be more reliable, than a small one.
We used for this project a Garrett GT3071R roller bearing turbocharger. How much power exactly? Well, this Suzuki GSX-R1000 has had a lot of work, a fully tuned engine by people from Big CC Racing in England, so it'll be good for 400bhp, maybe more. You can start off by bolting Big CC's modular turbo kit onto a standard Suzuki GSX-R1000 – that will give you something like 250 to 270bhp. The whole bolt-on turbocharger kit cost 180,000 Baht without import taxes.