[jrobson]

I'll look around later see if I can find the site.

Rovers VVC isn't infinately variable is it? (By that I mean lift from 0-XXmm in infinate steps)

There are distinct advantages that a infinately variable top end add to the system:
1. At low lift(part throttle) there are no pumping losses, this means that your BSFC figures are more steady accross the load range and in real world driving you will certainly use less fuel since a lot of driving is done at low loads.
2. At low lift the valve springs are not compressed much, so much less energy lost there, you may argue that the valves return much of the energy, however there is some lost, lets not forget much lower friction.
3. You can idle at 300rpm, a lot of fuel is saved in traffic vs a engine idling at 850rpm-1000rpm and remember those poor BSFC figures when the engine is under very low load. In any developed country, even here in our undeveloped country A HUGE AMOUNT of driving is done in traffic everyday by the average person. (Let's take an example, engine with 250g/kwh @ 2000rpm 75% load and with an infinately variable head vs a 200g/kwh @ 2000rpm 75% load engine with conventional head, if you sit in traffic for 45minutes at 2% load a day which engine would use the most fuel?)
4. Engine response must be quite nice, btw how is response with your sluggish looking bottom end? No offense of course, just saying it "looks" sluggish

My opinion is that if you want to put BSFC figures out, compare it to the industry standard at 100% load and let it be what it is, but of course that is just my personal opinion. If your graph is indeed correct then it looks like your engine is right around the same level as a very good conventional engine, but I could be wrong, perhaps everyone is publishing 75% results and not 100???

Edit: Okay I just looked at your site again and "14.5:1 of 238g/kWh (34.4%)" that looks "pretty much the same" as a decent conventional engine to me at the same ratio. Sorry I was just scanning this forum, though you got 207g/kwh at 14.7:1.