People in the Top Ten - Percent Above EPA Rating list...how do you do it?

[theholycow]

I saw that my car Effram had made it to 9th place in Percent Above EPA Rating before I retired it, and got the idea for this thread.

So, Top Ten - Percent Above EPA Rating people, how did you get there? What were your most successful strategies and modifications? What do you think didn't work?

[theholycow]

For me, these strategies/modifications are what worked:

1. Engine-off coasting. Effram was really good at it with electric power steering. Deciding when to EOC (vs. when to engine-on coast) is a matter of how long you'll be coasting, not how far. At lower speeds I'd EOC for short distances.

2. Pulse & Glide (engine-on) when EOC wasn't really appropriate. This was especially useful on the highway where Effram's short gears were a real handicap. P&G compensated for the short gears, even with a little fuel spent for double-clutch rev matching.

3. WOT + shortshifting. Low RPM, wide open throttle, using my gears to control my rate of acceleration.

P&G and WOT+shortshifting strategies leveraged Effram's decent torque, probably used the best BSFC conditions, and reduced pumping losses. They also reduced waste from extra revolutions worth of engine friction and reciprocation. It has been said that engine friction goes up as a square of RPM rather than merely proportional with it.

4. Tires at maximum PSI (51psi for Effram). This reduces rolling resistance and enhances cornering ability.

5. Avoiding brake use. Not slowing for turns, trying to plod through green lights instead of racing to red lights, etc. This avoids discarding energy that I've already spent fuel to make.

6. Grille blocking...honestly I don't think it worked for me but I did it so I'll list it.

7. Deceleration Fuel Cut Off. Effram wasn't cooperative enough for DFCO to be a major player. It helped, but not much.

[pgfpro]

So, Top Ten - Percent Above EPA Rating people, how did you get there? What were your most successful strategies and modifications? What do you think didn't work?

Strategy wise I use a well known test freeway. Its very flat and usually very hot during the summer months. On some sections I will use EOC. But for the most part I always look for semi trucks and draft them. Not to close though I don't want to put myself in danger or upset the driver.

Modification wise my biggest contributor is my lean burn engines. But I have melted a few down so its been a costly adventure.

My next biggest modification would be the tire pressure and new wheel bearings.

My biggest modification that didn't bring the results that I wanted is my newer engine running without a turbo charger. I knew right away that this N/A engine wasn't going to produce the numbers I wanted. So now I have to make a tough decision as what to do now. Put a turbo back on the Del Sol or keep looking for a good 91 CRX body to finish my testing???

[cems70]

My only mod is a full grille block in late fall, winter and through late spring. Besides that:

1. Tires at maximum pressure (and 5 - 10 psi over max since weather turned colder)

2. Engine-off coasting. I'm religious about this. I do EOC if it's at least 1/4 - 1/2 mile or if the engine will be off for at least 20 seconds (i.e. if I see a light turning red ahead).

3. Avoiding brake use. Gotta preserve the momentum.

4. Pulling all the way through into parking spots so I don't need to use reverse to back out.

5. Never letting the engine warm up before driving (only about 60 secs during the winter from a dead cold start to allow the oil to flow).

THC, it's hard to believe that grille blocking didn't work for you. I've been doing this for 21 years starting with my 1986 Honda CRX HF. It took so long for the engine to warm up that I figured blocking the grille would allow the engine to warm up more quickly. Same with my 1995 Honda Civic VX and my current Honda Civic DX (w/ VX tranny). It's been so long since I measured how long it took the VX engine to reach operating temp with and without the grille block. But if I recall correctly, it was around 1.0 - 1.5 miles less with a grille block during the winter. The other obvious benefit is better aerodynamics (eliminating the parachute effect). And the radiator lasts longer since small grains of sand, pebbles and other debris from snowplows don't sandblast and corrode the radiator.

I've never tried P&G because it's mentally draining to pay attention to it.

[theholycow]

cems70, I didn't have good purposeful scientific A-B-A testing for the grille block, but whenever I removed or replaced it I never was able to measure a difference. If you've driven mostly older Hondas, it's possible that differences in design and programming between older Hondas and a 2008 VW make it respond differently to that mod, although it's tough to imagine the aerodynamic advantage being meaningless.

P&G gives me something to do when I'd otherwise be bored. If I wasn't going to be bored then I can see it being draining.

[FrugalFloyd]

I don't enter my fuel log on this site, but my 90 day fuel record would put me in your top 10 with 74% above EPA. I do the same things HC mentioned in his second post, except I accelerate at 85% load per my Scangauge or Ultragauge (whichever one is plugged into my car).

I'll add going slow to the list of tips. A 45-60 mph P&G can get me 52 mpg. 25-40 mph in 4th gear can get me 60 mpg. 15-30 mph in 3rd gear can get me 68 mpg.

Steady state driving is the same way. 70 mph = 32 mpg. 55 mph = 43.5 mpg. 40 mph = 53.7 mpg. 31 mph = 54.5 mpg