The Society of Automotive Engineers sponsors a number of design competitions for engineering students, including MiniBaja, Formula SAE and SuperMileage. One of the newest is the Clean Snowmobile Challenge, started in 2000. Snowmobiles have had a well-deserved bad reputation for creating a lot pollution of both the air and noise variety. The school where I earned my engineering degree (once known as GMI and now called Kettering University) has a long history of participation in these competitions and they are showing their snowmobile at the SAE World Congress.
Competitors are judged on the performance of their snow machines including acceleration, efficiency, noise, cold-start, handling and more. They also have to prepare a technical paper and oral presentation on their work including cost and overall design. The current machine is based on a 2006 Polaris IQ with a fuel injected four stroke 749cc twin cylinder engine. The team at Kettering modified the engine to run on E85 and recalibrated the Bosch engine management system. On the output side they added a pair of custom three way catalytic converters which feed into an exhaust system using three mufflers in series. The handling was improved by using a shorter track that has the added benefit of lower weight, which benefits fuel economy. In their analysis the students estimated the changes would add $611 to the original $9200 price. Kettering finished 2nd overall in the 2007 competition.
[Source: Kettering University]