Phantom, Yes!
Lean Burn begins to raise its "ugly head" so to speak, again.
The Honda Civic Vx was a VTEC (variable cam timing) that had LB from 92-95 and consistently got 50 mpg highway. This was not an anemic 45 hp Metro XFi, but a robust 95 hp.
Officially, it seems that no US car maker openly embraced LB probably for fear of EPA wrath (I'm speculating!), however, the Japanese had another take for whatever reason and virtually every Japanese manufacturer had LB engines, many of which were sold in the US, but ALL were sold all over the world for many years.
There is talk that the Ford Escort had an "unadvertised" lean burn calibration that was sold in this country. I discovered this info while searching the internet for information relative to this thread.
If there was a LB map sold in Australia, it is entirely possible, Buick may have put some of them in service for some test program. It is also possible it may have been inadvertently been released to the public.
Inadvertently Released to Public: 1969 GM vinyl dash material: This particular year would not crack - even if baking in the sun of a junk yard with the window knocked out. My guess is that they received a tank car full of deviated material and decided to use it. It is pretty much an accepted fact that vinyl dashes crack with age. Unfortunately, a solution to that problem existed back in 1969.
Another thing that is interesting is the comment that TBs can be pretty tall geared: 1800 @ 60-65 mph is extremely tall. This would be very effective for mpg.
Also, I was thinking when was the 55 mpg federal mandate? I just checked and it was rescinded in 1987. Phantom, I wonder what some of your mpg, pure highway might have been driving the speed limit of 55? Almost no one drives that slow. If they were driving the speed limit during the road test I'm thinking off AND they measured an instantaneous 44 mpg while on the level, that might not be so hard to do.
Given the mass and HP of the car, ANY variation from perfect steady state cruise at 55 on level would result in significant reductions in mpg. Since they had the 5th wheel running, what they reported was meaningful because if it could be demonstrated, then it would hold for a pure highway trip in OH or the billiard flat Mid-West states.
If someone measures big mpg at 45-50 mph, while of interest, it is not a legitimate "highway" mpg spec since who drives 50 mph. This could be part of the explanation.
I think the big next question is did Buick ever use the lean burn maps on production cars. If they did, I would think it near impossible to confirm/document. The ECU code used on the Australian computers might be of interest IF it was ever found in a US car.
I move at the speed of awesome.
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