We’ve been trying to sort out all of the numbers being tossed around about the Thunder Star 1200 TDI diesel motorcycle. The more we looked, the less sure we were of anything. Close examination of several magazine writeups revealed different numbers within the same article! For instance, Streetfighters magazine had both 180 kilometers per gallon and 180 miles per gallon, an easy slip but quite a difference. The power output numbers are also a bit murky, with kilowatts and horsepower along with newton meters and foot pounds to deal with. The back and forth conversion errors seemed to be rampant everywhere we looked. So, I thought we should ask Star Twin to clear things up and I just received this reponse from the Thunder Star’s designer, Jeroen Bernart:
The ThunderStar 1200 TDI fuel consumption varies with the load of the machine. In a race setting the bike produce approx 95 bhp and 220 Nm of torque. When riding on the road (yes, the machine is road legal) it consumes approx. 5 liters every 100 km (race version). In addition, when we reduce the power output (approx 70 bhp, 160 Nm) the fuel economy comes close too 2 liters every 100 km.
It is difficult to provide accurate data, since it is still a prototype. This means we change a lot on the machine and have not done real fuel economy test. As for the power output, we are also experimenting with different mappings. This results in different power outputs so I hope you can imagine we can not give a final power output.
So, according to Jeroen, the output is 95bhp and 162 foot pounds in a race setting with fuel consumption at 85 miles per gallon. Reducing power to 70bhp and 118 foot pounds yields 212 miles per gallon! (Correction, 117 mpg. Thanks, Nick!)
I think we should wait on the final numbers for fuel economy since, as Jeroen said, they’re still experimenting and have not done a real test. It’s also interesting that he never mentioned the 250 foot pounds we’ve seen before though he did say 220 newton meters, a similar number though a different unit of measure, which may be the source of those previous numbers.
In all fairness to Star Twin, I think they have built a tremendous motorcycle and some of the numbers quoted probably arose from incorrect conversions of the numbers they gave out, an easy mistake to make with internatonal measures but, as with all things technical, something that should be checked. I am eager to see a controlled test to find out what the numbers turn out to be, however, I believe Star Twin has a real winner here which needs further development. This bike needs to be produced.
Previous posts on the Thunder Star: here, here, here, here, here and here.
hoyt says
Paul, any chance of finding a sound bite of this bike?
kneeslider says
There’s a brief video clip on the Star Twin site. It goes by and you can hear it but it’s not very clear.
Mark says
This bike sounds perfect, the hp and torque sound equal to that of the bikes during the late eightys and early nintys. The possibilities of mpg or kpg are astounding. If they are going to produce it let us all know it would be a motorcycle revolution.
Nick says
Just a quick correction. The 2L/100km converts to about 117mpg, not 212. Still excellent mileage though!
kneeslider says
Thanks, Nick. You’re correct. I recalculated and you’re right on, I have no idea where my original number came from. Batteries must have been low in my brain.
C says
Check out gizmag.com I think it is based in Austraila and they have a good write up on this new diesel bike.
From what I remember in the gizmag article, basically this is a prototype bike and they did everything they could to make it as light as possible, i.e. a lot of carbon fiber parts.
In addition, they made their own engine and transmission castings out of Aluminum.
100% Biodiesel can be run in any diesel engine. The only issue with this is that some older diesel engines need new fuel lines because biodiesel is an a cleaning agent. Also when you start running biodiesel it will actually clean out the gunk in your engine (if you were running petroleum diesel before).
VW TDI engines have no problem running on 100% Biodegradable diesel fuel, therefore I do not see why this engine would be any different.
Anders Glarbo says
Info has arrived in english :
http://www.startwin.com/pagina/bikes/special/thunderstar/thunderstar.htm#
Hans N Stol says
How soon will we be able to buy one of these?
And for how much?
Hans N Stol
Tom says
Clearly the wave of the future. Audi is slaughtering the gasoline powered cars in the Rolex Grand American and American LeMans Series, so it’s no stretch of the imagination to see this diesel powered bike become a major force in say 24 hour endurance racing.
Back in the early 1950s a Cummins 401 cubic inch straight six truck engine fitted with a crude turbo system almost won the Indianapolis 500. Thanks to it’s awesome fuel mileage no pit stops were needed. Imagine a diesel powered Indy car then in modern form.
And very enviornmentally friendly as well.
ADEILTON SILVA says
There are great news for those that loves diesel motorbikes.
We Brasilians are improving our ilimited Biodiesel (From mamona´s and animal´s fat).
Brasil got the fuel and the Europe got the power.
The future is in our hands.
John Sheldahl says
It only that bike was a twin, I’d buy a couple in a heartbeat and take them MOTO ST racing.
It would be very much like the AUDI’s clobbering the other racers in Grand Am and ALMS.
That would also make for one hell of a Sport Touring machine, probably the ultimate mount for the next big Iron Butt type Rally.