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Originally Posted by supermileage
It has also been suggested that we use a NiCom or Nikasil coating on the cylinder. Does anyone know more about this and the possible benifits?
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Sounds like you guys are off to the right track, the engine is truly where you are going to make or break your mileage. Our biggest focus points were the weight and efficiency of our engine. Both of these we did a ton of SimuLink and Matlab calculations and really found out aerodynamics play little role in the equation. I'm not sure if the rules have changed at all but when I was a part there were speed requirements (or should I say speed limits) in place and we discovered at the speeds we were traveling it played a very small role in the efficiency or performance of the car.
I would immediately suggest sleeving the engine but paying alot of attention to the thermal properties of the engine as believe it or not, the motor can obviously run "too cold". In most applications heat is of major concern (when it comes to robbing power) but since the motor runs so little I can suggest actually heat wrapping the motor to keep heat in. When we did it we actually machined off all the cooling fins and actually wrapped it in reflective heat (the gold foil type) shields, I know Laval uses simple aluminum foil to effectively do the same thing. There have been many good suggestions on the site but I would be careful when considering options as you want your motor to be reliable and trustworthy because having a motor that only starts 1/10 of the time is not friendly to deal with.
The biggest area's you will gain is by minimizing all losses of efficiency from where the fuel enters the bottle to the contact the drive wheel (and obviously front or "steering" wheels do). CVT's are by nature pretty inefficient and I think you would have better luck running detailed calculations and sticking with a fixed gear ratio than messing around with CVT's. Ultimately you would need such a small CVT and it would have to be fairly well tuned and precisely matched to your vehicles power outputs to the point it would become time-wasting to tune and match. Since you have an idea on the speeds you need to travel in the competition this should serve as a great baseline to begin calculations and simulations for optimum gear selection. Classically, direct drives or chain drives are more efficient than CVT's, of course a transmission could fix this but you have to ask yourself whether the extra weight/complexity of the project is truly worth the effort of investing time into.
Anyways, my 0.02 before heading out of the country for awhile...
Good luck and hopefully some others will put in their thoughts on this as well...