Ilmor One Drive

Ilmor's One Drive is jam-packed with updates that allow it to produce smooth power and offer new tech capabilities.
Ilmor One Drive
Ilmor’s One Drive is as powerful and exciting as it is jam-packed with user-friendly technological advancements. Courtesy Ilmor

Over the past few years, sterndrives have taken a back seat to large outboards. You might think that as a result, innovation in sterndrive propulsion would be stagnating. Happily, for sterndrive enthusiasts, this thinking couldn’t be more incorrect. Take Ilmor’s latest iteration of its vaunted One-Drive. This updated package is as powerful and exciting as it is jam-packed with user-friendly technological advancements. It’s as enticing to sterndrive boaters as a new hybrid Porsche would be to sports-car nuts. In fact, it’s appropriate to compare the Ilmor system to the highest level of ­sport-luxury ­automobiles. It is the Porsche of the sterndrive world.

Ilmor offers the One-Drive engine and sterndrive package in 5.3-, 6.0-, 6.2- and 7.4-liter versions. We tested and evaluated the latest twin 5.3L V-8 packages in Formula’s 290BR. According to Formula’s Scott Smith, this is the most popular setup in this boat. Performance was impressive, but the muscle is refined; the engines start instantly with no fussing, and idle very smoothly and at very low rpm (plus/minus 500). Shifting is quiet and uneventful, without the typical “clunk” of other drives. Acceleration is linear and smooth, with authoritative power that pulls hard to 5,300 rpm, which in the Formula 290BR equaled ­55-plus mph performance.

Integrated Power

These are the newest of the GM powerplants, very similar to the engines in the GM truck lines and the big SUVs (Tahoe, Yukon and Suburban). They feature direct-fuel injection and liquid-cooled exhaust manifolds, producing 365 hp. Ilmor also offers 6.2L and 7.4L versions. The Ilmor warranty covers five years or 480 hours on the entire system.

Ilmor partners with ­Yanmar in the drive engineering and construction. The drive ­employs an electromagnetic multidisk clutch pack for shifting instead of a cone clutch, which is older technology ­employed in other drives. This results in a much smoother, less jarring shift event, with far less wear and tear on the involved components. Smooth shifting is especially important where the Ilmor’s latest One-Touch joystick and anchoring feature is concerned.

The drives feature full trim and tilt function and a twin counter-rotating propeller gear case. Typically, Formula employs Yanmar or Mercury propellers on its boats. In our application, Mercury Bravo III stainless-steel props were employed (forward: four-blade 15.25-by-26 inches; aft: three-blade C/R 13.75-by-26 inches). The drives’ appearance is well-designed—sleek and streamlined, with a clean manufacturing approach and a robust, beefy presentation.

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Helm with joystick control
Joystick control is the most obvious technological achievement. Electronic station-keeping, trim assist, and more aid the captain. Bill Doster

Cutting-Edge Tech

The optional One-Touch joystick system is an engineering and electronic milestone achievement in high-end ­maneuvering technology. The drives are individually articulating in joystick mode. The joystick and control lever are well-­engineered and constructed, and give a high-end appearance. This is, of course, very important to the captain because look and feel shape so much of the ­experience when at the helm. 

A fully integrated Merlin ­Digital Dashboard ­Engine Display LCD screen is ­standard in the One-Touch system; it focuses on a hull-position indicator, fully integrated to show the boat’s orientation and ­position. The screen also shows drive-shift-position ­indicator (forward/­neutral/­reverse). Of course, the drives can be steered, shifted and throttled ­independently. A backup throttle/shift panel allows for ­get-home capability in case of an issue with the system. 

The system offers full 360-­degree rotational capability ­within a boat length. Complex maneuvers are fully integrated and merged. For example, when moving sideways and also turning the boat, those functions are merged into one smooth movement, where other systems move the boat sideways and turn it in two separate motions. The ­Ilmor system makes the boat act and behave more like an aircraft vectoring movement. If the operator wants to move the boat and rotate its position simultaneously (for example, while docking in a tight spot or orienting the boat for anchoring), the Ilmor ­One-Touch joystick does this seamlessly.

Anchoring Assist is another new and useful feature, and it’s really detailed. It features three different modes:

  • Heading: Also called “Sunset” mode, this locks only the heading and allows the boat to drift around the heading. 
  • Location: Locks the location of the boat but not the heading direction. Most often, this mode keeps the drives in reverse, and keeps engines in a low idle mode. This minimizes the shifting from forward, neutral, ­reverse and back again. 
  • Anchor Assist: Maintains heading and location. This involves the most forward-­neutral-reverse shifting, but due to the smooth clutch-pack design, Ilmor’s drive shifts so seamlessly that it’s barely noticeable, and it doesn’t place any undue stress on the driveline components. It also keeps the location tolerance very tight (about 1 foot!).

In Throttle Forward mode, the system features Smart Heading—a “­point-and-shoot” autopilot—independent of chart plotters. Slight ­steering-wheel movements can adjust your course; big movements ­disengage the mode.

Ilmor user interface
Big, bold, easy-to-see buttons are a hallmark of the intuitive control of the Ilmor graphical user interface. Courtesy Ilmor

Other systems might suffer from poor GPS reception when going near electrical lines or under bridges. Ilmor’s system incorporates three different ­independent measurement sensors: inertial, magnetic/­heading and GPS. All three sensors work together to provide input to the system for precise headings, with no input loss from outside-source interference. This is unique in the industry. If input loss in any ­parameter is experienced (for example, when poor GPS reception is experienced), the other two input sensors ensure that the boat stays on its ­prescribed heading.

Planing Assist (trim assist) is an electronic ride-attitude feature. The system is unique in that is uses a closed-loop ­input based on boat-fuel economy, unlike other systems that use an open-loop input that relies on rpm only to determine trim angle. The Ilmor system also detects porpoising, and compensates with trim-angle adjustments to minimize hull bounce. It’s easily overridden, simply by pressing the up or down trim button on the throttle lever. The system incorporates only drive trim, not trim tabs.

The combination of ­muscle and electronic refinement make the latest One-Drive package an extremely attractive option when considering a sterndrive for a new boat or repower. While the complete system is a bit intimidating at first and will undoubtedly require some time, study, and practice to become proficient in operating it, it’s ultimately very intuitive and therefore will quickly become second ­nature. A robust ­dealer network with trained ­technicians makes ­Ilmor technical support readily available. For sterndrive enthusiasts ­looking at a new boat or a repower ­setup, Ilmor’s latest ­One-Drive is a sophisticated package ­worthy of serious ­consideration.  


Ilmor Engineering Inc.

Plymouth, Michigan


Ilmor Marine LLC

Mooresville, North Carolina

844-GO-ILMOR (844-464-5667);,

Formula Boats

Decatur, Indiana