[CU2] To all the new Euro Auto owner out there!!!!

[SPQR]

Inefficient combustion? Doesn't sound like Honda.....
ECU tune FTW!

No it doesn't. But I've said it before: I think that the cause is the higher compression ratio of the CU2 engine compared to the CL9 engine. As Honda has said that they are working on a software fix, they'll probably retard the ignition timing (changing the compression ratio is not feasible) and/or adjust the VTEC in the hope of encouraging a more consistent charge mixture.

All measures that could potentially reduce power and torque.

The Honda bloke is wrong to describe pinging as pre-ignition: They are two different conditions as I had previously described. He has correctly described a post combustion event which is pinging/knocking but not pre-ignition. Pre-ignition of the charge by definition happens before the spark ignition. To say that a post combustion event does not lead to damage is not necessarily correct as it could increase pressures in the cylinder.

[Type R Positive]

No it doesn't. But I've said it before: I think that the cause is the higher compression ratio of the CU2 engine compared to the CL9 engine. As Honda has said that they are working on a software fix, they'll probably retard the ignition timing (changing the compression ratio is not feasible) and/or adjust the VTEC in the hope of encouraging a more consistent charge mixture.

All measures that could potentially reduce power and torque.

11:1 cr is sweet F.A. in the scheme of things.
Is it the cause of the problem? I doubt it very much.

[SPQR]

^^^ 11:1 compression ratio is considered a high compression ratio (up from 10.5:1 in CL9). Engines are more likely to ping/knock with a high compression ratio.

Some interesting info at Wiki: http://en.wikipedia.org/wiki/Compression_ratio


Some quotes form Wiki:

"A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air-fuel mixture due to its higher thermal efficiency. High ratios place the available oxygen and fuel molecules into a reduced space along with the adiabatic heat of compression - causing better mixing and evaporation of the fuel droplets. Thus they allow increased power at the moment of ignition and the extraction of more useful work from that power by expanding the hot gas to a greater degree.

Higher compression ratios will however make gasoline engines subject to engine knocking, also known as detonation and this can reduce an engine's efficiency or even physically damage it."

"Due to pinging (detonation), the CR in a gasoline/petrol powered engine will usually not be much higher than 10:1, although some production automotive engines built for high-performance from 1955-1972 had compression ratios as high as 12.5:1, which could run safely on the high-octane leaded gasoline then available."