A recent thread discussed inserting bike engines into a production car and how it was just not reasonable to attempt due to the production car simply being too heavy.

What is the average dry weight of a 2 passenger road going BEC?

Furthermore: Let's assume a 1 to 1.2 liter engine as a baseline and the goal is to run reliably (not burning a clutch every weekend) and have spritely acceleration.

At what weight does a vehicle become too heavy to be considered reasonable for bike power? 1,000Lbs? 1,200Lbs? 1,400Lbs? more?

Thanks for your responses,

You will have to get your convertor out but a good BEC IMO should weigh in at 500kg's max, i got under this easily and have sub 4 secs 0-60 times and 130 mph top speed.........

hope this helps......

I think it really depends on what level of performance you are after. Performance is usually a priority for people going the bike route.

I think you could get away with a car weighing around 1300 to 1350 lbs if you use one of the bigger bike engines e.g. Hayabusa or ZX12. The As One is in this weight range with a 230hp 1400cc hayabusa. With a stock Busa I still think performance would be brisk by normal road car standards.

For my car I am aiming for a weight of around 1100 lbs with a 230hp busa engine. This will give a power to weight of around 460 bhp/ton which should be sufficient! To give you an Idea, a 996 Porsche turbo has a power to weight of 260 bhp/ton and it ain't no slouch.

For a heavier car you will definately have to up rate the clutch. For the Busa there are plenty of options. If they can get a clutch to hold 300 ft/lbs in the Dax turbo Busa I don't think you would have any problems.

About 550kg seems to be the accepted limit for the litre+ engines, otherwise the clutches sh1t themselves. Below 1000cc, and the weight has to go down quite a bit too.
I race a ZZR1100 engine pretty hard, in an off-road car weighing 386kg, and have never looked at the clutch.