Team Challenge Results: What did you learn about FE?
This thread is intended to let team members talk about the things they did or didn't do during the Team Challenge to get better FE. What works? What doesn't? What was responsible for the increased FE?
I'd like to start by saying that the Team Challenge was one of the best things I could've done for better FE. If you look at my gaslog you'll see I was stuck around 38-39 mpg for months. I was set in my ways. I had heard about other driving techniques that help improve FE, but I never tried them, so I didn't know what I was missing. Entering the Team Challenge was like someone telling me, 'GO FOR IT!'
In a nutshell, I did two things that bumped my mpg up from 38mpg to a best tank of 45.5mpg.
First I started using Pulse and Glide properly. When I first started using this technique I didn't really see any results, probably because I was only gliding short distances, and the motor remained running. I also learned that the ecu has both an accelleration enrichment function as well as deccelleration enrichment. By frequently and quickly actuating the gas pedal on and off each time I began and ended a glide I was telling the ecu to squirt in a little extra fuel. So I learned to ease on/off the gas a little slower when going into and out of a glide.
The second thing I did right was to change my commute route. I had read about others who changed their route and improved their FE, but I was set in my ways. My standard route was direct, flat, and had consistent traffic to give me a corridor effect with frequent drafting opporitunities. (caution, I used to race road bicycles for over a decade, so I have excellent drafting skills, don't try this at home! or wherever ) So I didn't want to spoil a good thing. I knew of an alternative route that was just slightly longer but never considered it until I decided to take the scenic route home one day. My P+G habits kicked in and I found myself pulsing up mild grades and eoc down them. Taking that route just once while P+G'ing improved my FE and gave me a record tank without really trying! It's almost an ideal route for P+G: the hills are about 1 to 2 miles long with brief flat sections between the hills. I can climb the hills at 55mph in 5th gear (2k rpm) with engine vacuum around -5, (thank you omgwtfbyobbq for posting the VE graph) then eoc downhill at 55 to 65 mph for another mile.
The exit off the freeway is so perfect. It's like a surfer catching the ultimate tube ride. I can shut the motor off at about a mile from my exit and coast downhill. I'm still going about 50mph where the exit leaves the freeway, so I don't have issues with faster traffic. There the road turns uphill just enough to slow me to about 25mph for the cloverleaf offramp, which goes downhill again. There's no stopping after the exit, just a merge onto a quiet suburban road where the speed limit is 40. There's still no reason to turn the engine on yet since the speed limit drops to 35mph two blocks later. It's still downhill, if I'm lucky traffic will cooperate and I'll hit the 3 lights just right and keep coasting into the neighborhoods where the speed limit drops to 25. Next there's two stopsigns, so I'll start the engine and pulse up to 30mph, which only runs the engine for about ten seconds each time. I like to use 1/2 throttle to accellerate away from a stop while shifting at 1500 rpm.
Of course I had to use gas to climb up that hill, but the climb was done while the motor was in it's most efficient range (and lean burn helps). It's similar to how an Energy Efficient Appliance (like a refrigerator) works. The motor runs strongly for a short period, then shuts off. It's better than running lightly yet constantly.
DRW what an outstanding post. I also have gone over my commute route and found that by slipping over to a parallel street I'm able to hit the dreaded traffic light section of 4 light with better success. I'm now catching 3 out of 4 green instead of 1 out of 4. This alone has raised my FE segment by 2 MPG. I'm also finding that I'm walking and riding my bike more and if at all possible I'm driving during off peak hours.
The second thing I did right was to change my commute route.
That is also a big thing for me. I started taking my alternate rural route way more often to drive at lower average speeds. I have played with P&G a little but i need a kill switch to do it easier. Also should ask others with metro clones the best technique for P&G with this type of car. The injector kill switch will be coming to the metro experience soon .
Best tank= 81.23 mpg on july 1st 2008
SAVE SOME GAS, SAVE THE WORLD!
The one modification I made (the 1000 ohm "evry" mod shunt) was for a power improvement, not for an economy boost.
I chose to not do anything differently for the competition other than think further ahead and to anticipate better.
I didn't use P&G, EOC, codfish or anything else.
I didn't add wheel fairings, remove the interior and spare, add a grille block, or delete the power steering or alternator.
I did try a different route but went back to the original, "squandering" fuel because it saved time.
I ceased backing into the drive to allow a bump-start in the morning after one night.
I don't draft because I consider it to be 'tailgating' and just rude behavior.
I ran the tire pressures up to the 44 psi sidewall posted pressure but lowered them back within a few days because I didn't like the resulting ride.
I went back to summer tires a bit early, maybe not a good things since we are supposed to get 5-8 inches today.
I changed my oil to ELF CRV fully synthetic, I had planned to do it anyway but did it 2k early.
I stuck to the rural route instead of the highway to and from work/town, I typically take it to and from work but often when I am in town I took the highway home, but stuck to the slow way this tank. The slow way is actually less distance, but takes longer. 11 miles at 35 mph vs. 12 miles at 65mph.
Nothing else odd to the car, no mods.
On this tank (next cycle on the competition) I did disconnect the alt and hope to keep it that way for the entire tank. More to see what difference it makes then anything else. I have never ran it that way a whole tank (800+ miles).
You can bump start in reverse. Not sure if your set-up allows it.
Also, drafting doesn't have to be NACSAR-style. A safe following distance on a large vehicle can still help noticeably.
Reverse is almost an identical ratio to 1st. The diesel compression puts a lot of stress on the C/V and clutch. Third (at about 10 mph) is less stressful and allows continuing to roll forward once running. Bumping in reverse still requires stopping (in the street) before moving forward.
Drafting is less effective than I thought. Drafting a tandem UPS trailer set (long length and lower than most) last night had an instantaneous mpg of 75 mpg at 65 mph at about one car length. Dropping back to one second (about 100 feet) returned 65 mpg. Two seconds returned 60 mpg. A steady 65 mph with no lead returned about 55 mpg.