[ribiero]

I am very pleased to hear that Honda are working on a variable compression engine. I believe this could be a technological leap of efficiency for petrol engines. Saab manufactured many examples of these in the early 2000's, and demonstrated them at motorshows around the world. I recall seeing the specs, which seemed fantastic. from memory, the 1.6 could produce 240bhp using high turbocharger pressure and low compression, and conversely at high compression and lower turbocharger pressure performed as a 1.6 with high compression should, namely efficiently and miserly. It ran flawlessly too, the electronics controlling throttle openings ,with compression ratio, fueling, and boost pressure, were fully sorted, thus throttle response suffered less from turbolag than conventional turbocharged engines. Sadly GM cancelled the programme. I wouldnt want to suggest any conspiracy on GM's part, market reluctance for efficient smaller engines has always been a hard sell. It just appeared to me at the time, that a manufacturer that would be willing to cancel an engineering project with tangible benefits, couldnt claim to be engineering led. Good luck to Honda, a company that always innovates, and looks to exploit concepts, making them work mechanically. If not always financially.