Instead of posting why would someone argue over a topic not at hand or start a different topic in a thread just do not post.
Now on to my post.
Quote:
Originally Posted by Cardinal Grammeter
There was further talk in the thread that the mileage was due to a special super lean mpg chip that would "burn the pistons" if you laid into the gas. Which actually is a ridiculous remark since you could build a map that goes rich as soon as you develop load.
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That is one thing I did not include in my post about the different 3.8s the 3800 Series I (may have been Series II not sure about the switch over for them) sold in Australia used the OBDI computer after the US versions went to OBD 1.5/2. The computer there has a the PCM mapped out with Lean burn it is possible that the same or similar program was loaded on the US PCM in the car you are referring to. This part is only speculation but probable since the PCMs used in Australia for GM normally are several years behind the one the US version sold at the same time.
Back to the mileage at hand I currently drive a 98 Bonneville with all options other than the supercharger. In that car (see fuel log) I have achieved 29.2mpg mind you that it was mostly HW with many hills and it snowed during that trip and I averaged 70-75mph. I have similar experience with the 03 Grand Prix (~500rpm higher on HW than the Bonneville) on a trip from Cincinnati to DC in October I took the scenic route that has many steep inclines here most of the drive I was between 70-75mph. When driving HW only I saw 38mpg but that quickly dropped in traffic and I never had that on a tank.
Yesterday I drove to and around Cincinnati after filling up and had 26.8mpg down from the 36.7mpg when waiting for the light after getting off the highway. I made about the same trip home 5hrs later and when getting home I had 29.1mpg this was with a top speed of 58mph there and 67mph home over 35 miles with about 60% city. If the stall of the torque converter was lower I could have got better city mpg but it is a 2300RPM unit I know there are some as low as 1600RPM from the factory and units up to 3200RPM (I believe those are aftermarket only).
If you find any information on the differences I would love to know what they were.