Originally Posted by
Chip
Subtle differences in the angle of the pent roof, the shape of the transition from pent roof to the squish parts, valve angle, and also not just in the chamber but the way that the YB has a nasty angle in the exhaust port which hinders flow and results in more heat.
Massively complex subject, and not one Im really qualified to comment on beyond on the basics, I certainly wouldnt be capable of designing a head like the honda engineers etc do, takes years of experience and trial and error mixed with some massively sophisticated computer hardware and software.
You have to remember the YB was designed by a couple of blokes who didnt have anything like the data available today, and had to fit on an existing engine which constrained where oil and water ways and head bolts were etc which has an impact on design too.
Also the YB head was developed for about 20 quid as an internal project at cosworth, would have been a different story with proper ford money behind it right from day one.
I mean I'm aware what the engineering gap will mean between the two, something only the Japs can do is intricately refine on a budget, the German alternatives have always paid the price so to speak. Honda show up every brand in the industry IMO, so glad this green revolution hasn't sacrificed vtec too. Even they CR-V hybrids look trick... & massively tuneable.
TBH I'm glad mainstream Ford didn't get hold of the YB in the era the Cossie dropped, the fact they bolted so much to a boggo Sierra shell, if they'd gone into huge internal development the rest of the setup may have suffered, or keeping it to standard & pricing them well out the market, a la RS200... & what would Cossie owners have as fodder for the pound for pound brilliance that is the YB
skyline is 6 cylinders, that changes everything, as its got more valve area as a result of having the extra valves, so the same cam results in less opportunity for airflow on the YB
600cc's & 3000 revs make all the difference then, fair enough... again ignoring the 5 year engineering gap. If only they brought out new incarnations of the YB, that's where I'd want major Ford involvement! look how far the RB engine came before the R35. Ford could still hold real clout amongst the "EVO" elite. Far reach to keep the comparison going that long I know.
Issue got rinsed before the last FRS dropped, but still...