Hayabusa Low-Boost Turbo Kit

Hayabusa Low-Boost Turbo Kit

The ProBoost Low-Boost Kit does not require a cometic spacer, so the engine does not have to come out to accommodate the spacer. The turbo is literally bolt-on.

HardRider News Media
Nov 20, 2025
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The Suzuki Hayabusa has long been considered one of the most desirable motorcycles to turbocharge, thanks to its robust 1340cc engine and the extensive aftermarket support available for performance upgrades. Riders are drawn to the Hayabusa’s ability to handle significant horsepower increases, but one common hesitation for street riders is the perceived need to install a base spacer to lower compression from around 12:1 to 9:1. This modification is often recommended for high-boost setups, as reducing compression helps prevent detonation under heavy turbo pressure.

However, to combat this, ProBoost offers a Low-Boost turbo kit in addition to its Street and Race kits designed specifically for stock-compression Hayabusas. This kit limits boost to 4–5 psi, a level that the engine can safely handle without internal modifications. The key lies in how the kits are engineered to control and cap boost pressure.

How Low-Boost Kits Work

Wastegate Control: A properly sized external wastegate (commonly 38 mm) ensures that excess exhaust gases bypass the turbo once the target boost level is reached. This mechanical safeguard prevents boost creep beyond 4–5 psi.

ECU Tuning: Kits often include standalone or piggyback ECU systems with maps calibrated for low boost. These maps adjust ignition timing and fuel delivery to prevent detonation at stock compression.

Fuel System Upgrades: Even at low boost, additional fuel is required. Requires upgraded fuel pump and potentially upgraded regulator, and injectors to maintain the correct air-fuel ratio.

MAP Sensors & Boost References: A map sensor or similar device ensures the ECU accurately reads boost pressure and responds accordingly.

Reliability of 4–5 PSI Kits

It has been proven that stock-compression Hayabusas can reliably run 4–5 psi without engine damage, provided the kit is installed correctly and tuned properly. At this level, the engine typically produces 230–250 horsepower, a significant increase over stock while maintaining long-term reliability. The low boost avoids the extreme cylinder pressures that necessitate compression-lowering spacers.

Reliability hinges on three factors:
Consistent wastegate function to prevent boost spikes.
Proper ECU calibration to avoid lean conditions or detonation.
Routine maintenance of turbo components, fuel system, and sensors.

Conclusion

In short, low-boost turbo kits for the Hayabusa achieve safe performance gains by mechanically and electronically capping boost at 4–5 psi. This allows street riders to enjoy substantial horsepower increases without the expense and complexity of lowering compression. As long as the wastegate, ECU, and fuel system are functioning correctly, these kits are reliable and will not exceed the intended boost level.

Additionally street riders benefit with the ProBoost turbo kit because the kit uses the stock oil cooler and rad, so that normal use of street and highway riding keeps your Hayabusa purring and running without issue.

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