1451 Air Mass Metering

Air Mass Metering

28 September 2006, 67,777

bought myself a used (three thousand miles old) air mass meter for less than one third of the price Saab wanted for a new one. I figure, if it lasts beyond twenty thousand miles then I’ve saved money. Always handy that.

And the difference?

Well, yeah, now the TiD is working as it should. All of the problems I’ve been having have been, I’m pleased to say, caused by a duff air mass meter. Now there’s much less turbo lag and materially better performance. The joys of a variable intake tract and a multivalve head means that the engine will stretch towards 5,000 rpm. Quite where it reaches I’m not entirely sure but it will exceed the 4,600 rpm point showing on the tachometer.

However just a few days after replacing the air mass meter we hopped onto an airliner and flew to Kentucky, the United States of America for a family visit. This particular trip was a combination of road trip and family visit, though and during our time we visited a total of seven states including Kentucky. We spent most of our time in the family Toyota Prius or a rental Chevrolet Impala.

I’ve discussed the Prius elsewhere but the Impala was a new experience for me. We had a mid-range model fitted with a 3·9 litre V6 and a four speed automatic transmission. The Impala is considered a “full size” and this specification came with a slightly unusual specification including traction control, anti-lock brakes, manual air conditioning, electric sunroof, single slot CD / digital satellite radio system and heated leather seats. And you know what, it wasn’t _bad_, actually it was materially better than I was expecting in several respects.

First off it was a lot perkier to drive than most full size V6 American cars I’ve driven. I can blame the big engine and high power output (233 bhp) for this. The transmission is not especially smooth and has tall ratios, third being 25 mph / 1,000 rpm and fourth 34 mph / 1,000 rpm. The ride is more American than European but this makes it wallowly and comfortable. There is a degree of body roll even during moderate cornering and I only encountered understeer, just as I was expecting. In many respects then the Impala was simply “as expected.”

But there was one surprise: fuel consumption. Or lack thereof. Over eight hundred mostly freeway miles the car returned just shy of thirty two to the gallon. That’s a North American gallon though. In UK gallon terms the figure is closer to thirty eight. For a variety of driving conditions and speeds up to seventy miles an hour this is good going.

These sorts of consumption figures make me wonder why I’m bothering living in the United Kingdom... Over similar conditions I’d expect the Saab to return low fifties to the United Kingdom gallon.