Quote:
Originally Posted by enkeivette
No. If you lug hard enough you'll actually tip into the boost, well I will. Same goes for my mom's SRT.
What the other Adam is trying to get across is that an Avalanche (being a heavier car with more wind resistance) will have more load on the engine at the same speed/ rpm. And therefore be more likely to downshift and/or make less vacuum.
BTW I checked with my Mercedes Tech friend, and yes a vacuum reading is used to determine mpg. Once again more vacuum, more efficient.
Also, noticed that my friends Jeep Grand Cherokee 4L I6 Auto will downshift trying to maintain speed at 55mph on the 15 freeway going up a slight grade.
C6 Standard Equip:
3.42 Diff
T56 .5 OD (6th)
285 35 19 = 26.85"
1177rpm @ 55mph  Do I even need to say anything? C'mon. |
Ugg, this is getting so stupid. First of all, if you're just CRUISING on the freeway, 55mph at 1177 rpm would be JUST FINE. I was cruising in the Cobra yesterday in 6th at 55mph and my RPM was about 1400. Guess what, it was no big deal. If I needed to go up a grade or something, I would downshift to do it. Otherwise, the car could quite happily cruise at that speed and RPM for hours no problem - and I would get better mileage than if I was going 75mph. Again FOR MOST CARS, going 55mph will net them better mileage than 75 and the car would have no problem doing it in overdrive. Also most cars, especially automatics (which comprise a huge percentage of cars on the road) can easily be in overdrive comfortably cruising at 55 and again would get better mileage than 75.