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Old 09-04-2020, 06:12 AM   #76
Join Date: Sep 2020

Hi folks,

Complete and total thread necromancy here, but this thread comes up as one of the top hits on google when searching for info on heron heads (congrats!), so I thought it was worth putting some information here that might be useful around the likely context for the B230K and why it might not have been developed further.

During the mid-to-late 80s, manufacturers were expecting the next big wave of emissions legislation in Europe. At the time, it looked like the future was in lean burn engines, running with ultra-efficient combustion to reduce hydrocarbon output and improve economy. My main knowledge around this comes from the Rover M16 engine which was developed around this time to run on mixtures as lean as 18:1, but I expect the B230K was developed in a similar set of circumstances. Ford Europe and Peugeot were doing similar things at the time too. These engines require very efficient breathing, and a design that's resistant to knock (a benefit of the Heron head).

Unfortunately for these manufacturers, when the Euro I legislation actually came through i 1992 it was much more stringent than anticipated, fuelled by a surge in environmental concern about other noxious gasses produced by engines (principally NOx, which lean burn engines produce more of). The only real solution to these new rules was using catalytic converters to treat emissions downstream (which don't like lean burn engines). So, most of the lean burn designs (either in production, or being developed) became dead ends overnight. It's probably this that killed the B230K head, and why it wasn't developed further.

It would be very interesting to see what a turbo'd heron head might do, given its efficient porting and resistance to knock. I know the O-Series turbo used a heron, but a lot of the information about that seems to have been lost with the moving of the Rovertech forums to FB. The VW VR6 engine is also a Heron that seems to have been turbo'd quite well, but like hell I'm wading through VW forums to find good information on it!
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