As I was searching for more documentation on the Thunder Star torque, horsepower and rpm figures, Andy, who is conveniently located over in the UK, was kind enough to forward an article that appeared in the March 2005 issue of the UK magazine “Streetfighters.” Their writeup had a few more details on construction but some of their numbers raised even more questions.
Their article cites mileage of 180km per gallon which translates to about 111 miles per gallon, which is still great but a bit off the 150mpg figure.
Their numbers for horsepower and torque are the same as the Sport Rider article:
80 horsepower
165foot pounds at 4500rpm
Remapping yields:
120 horsepower
250 foot pounds at 5500rpm
Something just doesn’t sound right here …
They also mention the search for investors so they can move the bike to production, that scary period when you hope to keep the bike alive and hope someone else doesn’t beat you to market.
What’s the real story? We’re on the trail and will continue to report as more info comes in. To be continued …
Andy Pugh says
The hike from 80 to 120hp sounds plausible to me, all you would need to do would be to give it more fuel and more boost.
I work on diesel engine mapping and the degree of control we have over the engine with modern control systems is immense. The hard limits are nearly all to do with either turbo temperature, emissions or durability. The engine is going to spin up so much more quickly on a bike than a car that the turbo will have an easier job. A slightly higher spec turbo would add a disproportionate amount of headroom too. Emissions rules for bikes are very different than for cars, and lets be honest, you don’t need the same durability in a bike as a car, 100k miles will be enough for most people.
The bike duty cycle might also help. It makes very little difference to durability going from a potential 80 to a potential 120 if the bike spends 90% of its time making 60hp.
bob fedyski says
Why should a bike’s durability be less than a cars’? I don’t think 100,000 mile durability is acceptable.
That said, with fuel prices going where they are, economy sells. Link that to fun and seems one would have a hell of a product. I’m lookin’ forward to the chance to get a bike like this. Probably 70% of my travel is by motorcycle, and the potential of a bike like this will bring a lot of new riders to the road, and we all know that the more people that ride, the more awareness of riding is created, making it safer for all.
Andy Pugh says
100k miles is a long way for a motorcycle, there is no two ways about that. Average annual mileage for a bike in the UK is aboiut 3k, I think. I have taken a couple of my bikes past 100k (I gave away my FJ1100 at 137k miles) and engine life wasn’t the issue, but that point the rest of the bike was worn out. (Bodywork cracking up, suspension worn out, corrosion, just plain ugly). Having said that, the FJ could have really used a rebore at that point, so you could argue that the FJ, a famously durable bike, was worn out at 100k. I would be surprised if more than half the bikes out there make it as far as 50k without being scrapped for other reasons.
I hate to think how little my 36kmile 2004 R1 is worth now.
But my main point came later. You can’t run a bike engine at 120 hp for very long before you have to slow down. Even with 120hp max power the bike is likely to spend most of the time running at constant speed and 40-50 hp at most, at which point the higher potential power has no real effect on durability.
bob fedyski says
I guess I was spoiled. I rode beemers for 25+ years. The old airheads were well known for going over 100,000 miles. Actually, many were known for 2 and even some 300,000 mikle bikes. This was back in the late ’70’s. ‘Til rearranged body parts, I rode 15,000-20,000+ miles a year, and had no trouble riding a bike (BMW airheads) a couple of years and selling for the same I’d paid. Currently on a Triumph Sprint w/ 53,000+ miles, but resale is shot. It’s still a great bike, and I’ll probably put another 50,000 miles on it.