Posted: Thu Nov 17, 2011 1:06 am
As you said, an Australian-only harness would make things more expensive.
So why the change to a mechanical dizzy & ECGI?
Was it so that we could have more pollution than California?
(And I think Japan had tighter controls than USA & Ca anyhow. Certainly the new Tokyo diesel nano-particle standard is or was the toughest in the world. In fact Isuzu was the only diesel to comply.)
And how the heck refabricating a mechanical dizzy with its new timing can be cheaper than re-mapping an existing system beats me.
The knock control doesn't make sense. It is easier to retard timing digitally than to successively retard etc with analog circuits.
But the knock control on the ECGI/Jetronic Piazza does that irrespective of the mechanical dizzy's timing - it retards the dizzy's firing point (or rather, it adds less delay) and it would simply do the same to a mapped firing point.
And to add it to any mapping is easy - it's essentially just a few lines of code (if knock noise is there, retard x-degrees; if still there, retard again; if no knock start advancing (or after delay, reset to map) etc etc). But if not, do it as per my last paragraph.
The move back to a mechanical dizzy still makes no (technical or fiscal) sense to me.
The body manufacture method (or prod line) changed in 1985 or 1986. Although the bodies looked the same, the later body was a better construction.
At the time the Aussie order was placed, the body ordered was officially superseded.
So was it that GMH were slow to approve a much earlier proposal, and decided that programmed ignition was far too advanced for mere Australian mechanics or maybe too money-saving for customers?
Did GM influence GMH to further GM's politics with Isuzu (or GMH!)?
Hmmm...
So why the change to a mechanical dizzy & ECGI?
Was it so that we could have more pollution than California?
(And I think Japan had tighter controls than USA & Ca anyhow. Certainly the new Tokyo diesel nano-particle standard is or was the toughest in the world. In fact Isuzu was the only diesel to comply.)
And how the heck refabricating a mechanical dizzy with its new timing can be cheaper than re-mapping an existing system beats me.
The knock control doesn't make sense. It is easier to retard timing digitally than to successively retard etc with analog circuits.
But the knock control on the ECGI/Jetronic Piazza does that irrespective of the mechanical dizzy's timing - it retards the dizzy's firing point (or rather, it adds less delay) and it would simply do the same to a mapped firing point.
And to add it to any mapping is easy - it's essentially just a few lines of code (if knock noise is there, retard x-degrees; if still there, retard again; if no knock start advancing (or after delay, reset to map) etc etc). But if not, do it as per my last paragraph.
The move back to a mechanical dizzy still makes no (technical or fiscal) sense to me.
The body manufacture method (or prod line) changed in 1985 or 1986. Although the bodies looked the same, the later body was a better construction.
At the time the Aussie order was placed, the body ordered was officially superseded.
So was it that GMH were slow to approve a much earlier proposal, and decided that programmed ignition was far too advanced for mere Australian mechanics or maybe too money-saving for customers?
Did GM influence GMH to further GM's politics with Isuzu (or GMH!)?
Hmmm...