The current 2017-2018 ruleset brought a few big changes to Formula SAE, the most exciting being a significant increase in the maximum allowable engine displacement from 610cc to 710cc. This change has upset the current status quo, and meant that several new engine options are now in play, dramatically expanding the range that teams can select from (four cylinders, V and parallel twins, and singles). Monash Motorsport conducted a period of intense research and simulation between late 2016 and the early stages of our 2017 Design Period to try and decide which engine would ultimately be the best fit for our team for the next two to four years. Our requirements for a good compromise of power and weight led us to select the new single cylinder KTM 690cc Duke-R engine for 2017, which we plan to run naturally aspirated.
The single, 690cc cylinder, sits in contrast to the four cylinder configurations used by many of the other teams in the competition. In our experience, a single cylinder provides a number of significant advantages over multiple cylinder engines, with one of the most critical being power to weight ratio. While a four cylinder engine of the same capacity can produce more power, the additional weight it brings can undo this benefit – particularly in dynamic events where cornering speed is critical. The 690cc Duke-R is also expected to produce a large amount of low-end torque, a characteristic shared by many single cylinder engines.
Monash Motorsport has elected to run the engine using natural aspiration. While a well implemented turbocharger can deliver an attractive performance boost, it adds complexity to the design and tuning of the powertrain package. With our ambitious goal of fielding ‘one team, two cars’ this year, we’ve made the decision to run a simple yet effective design.
Using a naturally aspirated engine will see improvements to driveability of the car, in particular the elimination of ‘turbo lag’. Turbo lag is the apparent lack of engine power that occurs when the driver first begins to accelerate, a phenomenon caused by the turbocharger requiring high velocity exhaust gasses to be effective. We are eagerly anticipating the improved throttle response of the car as it accelerates, particularly out of hairpins.
Finally, the KTM 690cc Duke-R promises exceptional reliability, boasting a service interval of 10,000km – a drastic increase over the 50 hour service interval of the KTM 500cc EXC. When combined with the lower complexity through the removal of our turbocharger, Monash Motorsport aims to complete our most aggressive driving target yet – 900 testing kilometres before competition.
Monash Motorsport has benefitted greatly from our partnership with KTM, which began in 2011. The Monash Motorsport team would like to express our gratitude for the advice and support the KTM team provides, and we look forward to continuing to achieve great results with KTM engines.
– Michael Strauss (Combustion Powertrain)