I've a couple observations and questions. In the past three months I purchased a 2000 7.3 PSD Excursion. Being an avid hypermiler, I was able to average 17mpg in mostly city driving. Then the injectors started failing, among other things. So I upgraded to single shot injectors and tuning from Beans Diesel. Mpg has not improved, in fact I have yet to get as good of mpg on thier Economy program as I was getting with a terribly misfireing stock tune, now 16.5mpg. With my scangauge in the EX. I can clearly see the instant mpg increase as the I switch the chip to the more aggressive settings. I have been running in the second most aggressive setting for this past week and the average has increased by a couple mpg, will probably be around 18mpg. It seems most economy tunes just limit the fuel delivery on acceleration so lead footed drivers won't shoot themselves in the foot. Doesn't help at all when you foot is well trained. I'd like to see one of these aggressive tunes with low shift points on the ATX
Now concerning air dams...I would like to add one to the Ex., but I am concerned reading that Big Dave says his air dam, at 9" off the pavement, does not help mpg. Is that True? It's funny that my post at the begining of this thread says to go as low as possible (my escort is only 2" off the pavement) but now that I am faced with this for my wife, I must consider curbs and such because she will hit them and will not tolerate any noise of the air dam scrubbing the ground. I need to figure out a happy middle ground.