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SeaStar Calibur XSi 9.0L | Extreme Offshore Racing Engines

Today at SeaStar Marine, we introduce to you, the XSi 9.0 - Our first inboard-sterndrive race engine.

(Based off the Mercury Dual Cal)[www.mercuryracing.com]

Previously, we brought you the best high-performance racing outboard you could get, the 500R. This time, we’re bringing you the best inboard race engines you can get, the XSi 9.0.

As all current SeaStar powerheads, the XSi 9.0 is built on our XCQV engine architecture platform, ensuring that your engine makes power and stays reliable for years to come. The XCQV platform, in basics, represents that the powerhead utilizes dual overhead camshafts, driving 4 valves per cylinder, which allows us to make extreme power while still optimizing efficiency.

The large 9 Liter (550 CUI) displacement allows for us to overbuild the critical power making components of the powerhead, allowing it to run hard at redline for up to 225 hours before any intensive teardowns or inspections are needed. SeaStar recommends the first minor service of the powerhead at 75 hours.

The advanced high-pressure twin turbocharging, and fuel optimization technology allows us to reliably make a substantial 1100 HP at the bottom-most tier engine, and a wild 1750 HP out of our peak race engine.

The overbuilt truck-engine style big block nature of the XSi allows it to rev all the way up to 3300 RPMs reliably, while driving a nearly linear torque curve, pushing your vessel on plane and up to crazily high speeds in mere seconds.

Included with the XSi, comes SeaStar’s tested and proven XT8 stern drive, as well as the XTR racing transmission, already linked to the electronic management, making this sterndrive unit as plug-n-play as we can make it.

Rivaling the power, efficiency, power density, and torque of even prefab engines .. the XSi is a force to be reckoned with.

Internal Model Name – IRX-8-9TT
Powerhead – 9.0L DOHC Tiwn-Turbocharged V8 (1100 to 1750 HP)
Transmission – SeaStar XTR Inboard Transmission
Lower Unit – SeaStar XT8 Race Drive
Electronic Management – SeaStar RaceDeck COMP
(default color schemes vary from power packages)

Air/Fuel Controller
Smooth RPM Limiter
Ultra Compact Infinite Generator

Try The Caliber 9.0 For Yourself!

The sterndrive lower unit does not need to stay fixed to the transmission. You can remove it, place it wherever It performs best on the vessel and pipe a driveshaft to it.
If the engine is not running, make sure it has all of the critical things an engine needs to run. Air, and fuel.
By default, this engine has air intakes on the cold (compression) side of the turbo, meaning that if you place it in a sealed compartment, it may be starved of air and not run.
To solve this, you can either de-seal your engine compartment, or you can run intake piping to the outside of the hull.
You do not have to use the included heat exchanger. Just find a cooling solution that works.

This engine runs hard and revs high. It is prone to overheating. It is not my problem if you run it with overheating turned on.
These engines are no joke, if you do not have your vessel stabilized, you will most likely just flip up in the air before getting to any high speeds.

Join the Stormworks Offshore Racing Group if you’d like to chat with me about boatbuilding or help with SeaStar products.