Quote:
Originally Posted by UltArc
Today, I drove 38.1 miles in one direction, getting 39.8 mpg w/ cruise control locked on at the speed limit. This did include getting started in a parking lot and waiting at a red light, hurting mpg.
2.9 miles @ 55mph
12.3 @ 65
22.9 @ 60
I later drove this backwards ( the opposite direction, return trip) and saw 40.2 mpg. Temperature was not noticeably different, one trip from 0930, the way back was at 1800.
Of course when I usually drive, I speed, and hypermile. So EOC, and cruising at 4-9 over, building on down hills, losing speed uphill- usually engine on performance gets me 35+, not including my EOC.
I originally paid attention to this because someone on here (couldn't remember who) brought up something along the lines of not knowing about a vehicle getting 30+ mpg at 70 mph. So I thought I would keep track, find my rough figure on the Cd chart, and look to see at 70 mph.
Anyway, knowing my vehicles info (wet/loaded weight, frontal area), general driving figures (drag from road, air density), I am trying to calculate my CD by looking at the tool for it. I was placing lower and lower to find, but putting in .2 for CD gets me 35 mpg at 60 mph. I know my CD is NOT that low, yet I was getting BETTER mpg.
Does anyone have any tips, help, or ideas on it?
|
*You've got to have a baseline MPG for the stock vehicle determined at the same speed as future testing will be accomplished.
*You need to be fully warmed up before you begin any testing.About 23 miles of steady 50 mph driving is the minimum.
*Top off right next to the highway you're going to do your testing on,get on the road directly,and up to speed, and then hold that speed as constant as you can before you stop for fuel again.
*Or drive as far as 1/2-tank,then do a u-turn.
*Run the reverse leg and return to the same station where topped off,at the same pump,parked in the same direction.
*Top off the tank.
*Divide your miles by you gallons and see where you're at.
--------------------------------------------------------------------------
When you have this baseline any new drag coefficient will be easy to reverse-engineer from the new mpg at the baseline speed.