Daily Log = 40% better FE in 40 days

[Diesel_Dave]

I wanted to encourage everyone out there who drives a regular route to keep a daily log. I started mine back in May and over 40 days (work days) I've improved my FE by around 40%. According to my in-cab display the average of my first 3 days (6 trips) was 29.1 mpg. The average of my last 3 days was 41.2 mpg. FYI, I know it reads ~15% high. I went through 4 tanks and my 1st tank was 25.74. My last was 33.91. That's a 31.7% improvement.

I've done a few physical mods (upper grill block, bed cover, tire pressures), but most of it has been driving style and route selection. I actually didn't spend any money at all on mods during the 40 days.

So if you're not keeping a log, I would encourage you to start. I found it helps a lot to see what's working and what's not. It's also fun to see how well I can do. Every day you see if you can set a new record.

[JethroBodine]

Alright Dave. Thanks for feeding my OCD. I'm now keeping a log and will see if I can get another 40%out of my car. I'll try to make a nice graph( not as nice as yours, I'm sure) to see what's what.

[graydonengineering]

Nice improvement! I have kept a log for over a year now and it has proved very valueable! Becasue of my log, I know I improved mpg by more than 2 miles on average after getting a scan gauge. I also can see just how much my AC kills my average.

[Kodak]

That's impressive. What is it about mornings that make for better numbers? Traffic, temperature? Or maybe it's not the time of day at all, but the fact that your return trip is uphill.

[SwamiSalami]

Originally Posted by diesel_dave

i wanted to encourage everyone out there who drives a regular route to keep a daily log. I started mine back in may and over 40 days (work days) i've improved my fe by around 40%. According to my in-cab display the average of my first 3 days (6 trips) was 29.1 mpg. The average of my last 3 days was 41.2 mpg. Fyi, i know it reads ~15% high. I went through 4 tanks and my 1st tank was 25.74. My last was 33.91. That's a 31.7% improvement.

I've done a few physical mods (upper grill block, bed cover, tire pressures), but most of it has been driving style and route selection. I actually didn't spend any money at all on mods during the 40 days.

So if you're not keeping a log, i would encourage you to start. I found it helps a lot to see what's working and what's not. It's also fun to see how well i can do. Every day you see if you can set a new record.

nice.

[Diesel_Dave]

Originally Posted by Kodak

That's impressive. What is it about mornings that make for better numbers? Traffic, temperature? Or maybe it's not the time of day at all, but the fact that your return trip is uphill.

There are a few reasons for that. I think the biggest factor is that, for most of the days in the log, I made a stop on my return trip. We're in the process of moving to a new house. We bought it at the end of May and it needed quite a bit of work. I stopped on the way home pretty much every day, did about 2 hours worth of work, then went the rest of the way home. I think the biggest FE hit came from the fact that everything needs to warm up again. Another part of it is that I have to drive an additional 1 mile into and 1 mile out of the neighborhood (lots of unavoidable stop signs).

That being said, we moved in to the new house 5 days ago (after the data you see in my bar chart), and my morning commutes still tend to be better than the evening ones. I'm still trying to figure out exactly why. There's no significant elevation change--it's pretty much as flat as a board here in most places. It's warmer in the evening, but in general the higher temps help me at least a little (when I compare morning to morning ot evening to evening). I think traffic is the biggest factor--it tends to be heavier on the way home for whatever reason, so I can generally do less P&G.

Here's also another thing that may be making a difference: My commute is mainly highway with a few miles of in-town driving on both ends (unavoidable stop signs, etc.). There's about 1 mile of in-town near my house and about 3-4 miles of in-town driving near my work. I wonder if that may make a difference. I know my efficiency stinks before things warm up. I wonder if the combination of warm up and in-town make things really stink. If the engine is warm (at the end of a trip) maybe in-town only slightly stinks. In the morning I only have about a mile of really stinky efficiency & 3-4 miles of slightly stinky efficiency--in the evening I have 3-4 miles of really stinky efficiency and 1 mile of slightly stinky efficiency. Just a theory, I don't know.

[Diesel_Dave]

Originally Posted by JethroBodine

Alright Dave. Thanks for feeding my OCD. I'm now keeping a log and will see if I can get another 40%out of my car. I'll try to make a nice graph( not as nice as yours, I'm sure) to see what's what.

Thanks!

If you get another 40% out of your car that would be totally awesome. Maybe I'm wrong, but I think driving style makes a much bigger difference on a big, heavy vehicle like mine, as opposed to a lighter vehicle.

IMO, if you drive correctly you can largely offset the effect of increased weight. If you drive "normally" with a heavy vehicle you leave tons and tons of energy at each stop sign & red light. By timing the red lights and costing up to stop signs you can get a lot of that energy back. With a lighter vehicle there's not as much room for improvement.

[slowmover]

I wonder if the combination of warm up and in-town make things really stink.

I guarantee it does.

When I am trip-planning the weekend "errands trip" I always use the non-stop route to the freeway (1.5 miles farther at 3.8 miles) as the stop-n-go absolutely kills mpg in a 7k+ diesel truck. (I run all miles town or country at 1,700-1,900 rpm, cold engine or hot). Then I use the freeway to go to the farthest point of the errand trip. The farthest point may be past the closest path to the first stop, but avoidance of stop-n-go is paramount.

When I first had this truck -- and living in this city -- I averaged 18-mpg in-town the first calendar year. Nothing special in driving style (for me). The last two years that average is 20+ mpg/city for the same work, but the addition of trip-planning made the difference. (I drop below 20-mpg due to extended idling for A/C use in June/July/August/September).

If possible I use a RHTO (right-hand-turn-only) plan from the first errand stop to the other stops as I/we make my/our way back to the house.

But avoidance of stop-n-go trumps all other approaches.

Imagine that you had a 1973 Chevy 454 P/U hooked to a heavy trailer (worst year for emissions devices and worst of the big blocks for fuel economy) to make your run. 4-mpg for quite a ways. Worse in stop-n-go.

I can do the same in the wife's 2WD XJ, but the spread in mpg is not nearly as large, nor is S&G penalized quite the same, so RHTO works a bit better in it.

FWIW I couldn't agree more about record-keeping. But it should also, IMO, be tracked against temps, etc. These are basic. The changes I am willing to make need to be balanced against always doing them, so until a compromise is made one needs records to backstop the work.

Thus my additions to your other thread about temp control/heaters. Your employer may not allow you to plug in while at work, but front-loading the morning commute with a "warmed truck" might offset the S&G penalty in leaving work, etc. Or, an ESPAR or WEBASTO heater.

I cannot remember if you have manifold pressure & exhaust gas temperature gauges; if not, both of us need them to do our fine tuning.
600-60-6, or, 600F EGT or less, 60-mph or slower, and 6-PSI or lower.

.

[Diesel_Dave]

Originally Posted by slowmover

I cannot remember if you have manifold pressure & exhaust gas temperature gauges; if not, both of us need them to do our fine tuning.
600-60-6, or, 600F EGT or less, 60-mph or slower, and 6-PSI or lower.

.

No, right now I haven't added any instrumentation to the engine yet. A Scangauge could give us intake temp & pressure as well as exhaust pressure. EGT would have to be added as there isn't a stock sensor for it.

Right now, my problem is the time to do all the stuff I want to do

[Diesel_Dave]

I just saw #28 on the list of 100+ Hypermiling Tips:

28) Combining errands: do the longest leg first
When combining multiple trips into one journey, go to your farthest destination first, and work your way back. This ensures the vehicle is warmed up as much as possible before subjecting it to multiple starts and stops.