World Solar Challenge – can they make it?

Prompted by a comment by Puplah on today’s snippets post, I just did a little research and some calculations. Team Ethanol are participating in the World Solar Challenge and driving a Saab 9-5 BioPower SportCombi in the alternative fuels category of the event.

The question at hand was whether or not they have enough fuel to get there.

Here’s their fuel supply, from their own photo set at Flickr.

Team Ethanol

That’s a 200 litre drum. Add the fuel tank in the 9-5 and they’ve got 275 litres total supply.

The journey from Darwin to Adelaide, in general terms as I don’t know exactly where they’re starting or finishing, is 3,027 kilometers.

Assuming it’s a manual vehicle (lower consumption), the Saab 9-5 uses 6.8 litres per 100 kilometers, but that’s on petrol. If we use the 30% rule of thumb as advised on the Saab UK website then that brings the car’s fuel consumption on E85 up to 8.84 litres per 100 kms.

With 275 litres of fuel, that means they’ve got 3,111 kilometers of fuel at their disposal. I know there’s not a lot of traffic lights between the two cities (like, none) but they better hope that:

    a) they have a tail wind.
    b) they don’t have too many stops or delays, and
    c) they don’t spill any fuel when they’re refuelling.

84 kilomoters of reserve ain’t that much. It’ll be interesting to see.

And if there’s something wrong with my math here, please let me know.

E85 calculation

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  1. Have they done any mods on the car?
    Some ultra-low resistance tires in a narrower size might get them 5% further.
    They could also remove one side mirror and tape-down the grille and door seams to gain a bit. I am surprised that they are keeping the roof rack.

    I assume that the 6.8l/100km is the official rating. I am sure that Team Ethanol will have figured out what speed they need to run in order to get the absolute best mileage.

    Are they allowed to draft other cars? That can give a significant advantage.

    For those who don’t know, drafting is the practice of following another car very closely in order to gain an aerodynamic advantage. This technique is the only way to win a race at Talladega.

  2. Well, I’ve worked with those drums in a previous life….
    The drum actually contains 210 litres if you tip it of. The drum actually contains 210 litres if you tip it of.
    So it would get them another 110-120 km, right?

  3. As I commented in the earler post of this thing, if the car has been properly run in (20-30k km) and they average 90km/h then they should get an average consumption of about 8,5-9 litres/100km.

  4. At a steady 100kph, my regular old-fashioned petrol manual 9-5 can roll up and down a highway at 6.5l/100km.

    If I cruise at 80kph ( which is next to impossible for me – it is against my religion) I have been able to get that down to 5.9l/100kph. At one point on the eastern freeway in melbourne (a very smooth, flat piece of tarmac) i’ve even had the average read out to me as 3.6l/100km.

    If they were to aim to stay between 60 and 80 kph in 5th gear, use no more than 1/2 throttle and only use the brakes when they’re about to run someone over, thy can manage much better that 8.84, i’m sure.

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