MPG? (Hypermiling, Scanguage question)

[rfernatt]

Originally Posted by forestacademy

Sudo Bump

I woke this up to ask it get moved to the MPG section of the site

Done. (Hopefully correctly...)

[rfernatt]

Originally Posted by gurps

I would think that IF the fuel is cut off when coasting in gear, then this would be the most efficient instead of coasting in N and then braking a lot. OTH, coasting in N where you will not be coming to a stop at all, but will have to increase speed at some point, I think, would be more efficient.
I have a DashDaq and I'll have to see what OBDII parameters it has that I can record, to find out if there is actually a fuel cutoff


T

Fuel is cut when coasting in gear in both the smart and my automatic Frontier according to SG II. The MPG gauge goes to 9999 MPG and the GPH gauge reads 0.0. I have a 1.5 mile hill I coast down every morning in gear.

[T12121]

Originally Posted by rfernatt

Fuel is cut when coasting in gear in both the smart and my automatic Frontier according to SG II. The MPG gauge goes to 9999 MPG and the GPH gauge reads 0.0. I have a 1.5 mile hill I coast down every morning in gear.

if you adjust your cutoff it will show it correctly for you MPG and GPH. The only time I see 9999MPG is when I have the engine turned off.

[gabe1475]

Originally Posted by gurps

I would think that IF the fuel is cut off when coasting in gear, then this would be the most efficient instead of coasting in N and then braking a lot. OTH, coasting in N where you will not be coming to a stop at all, but will have to increase speed at some point, I think, would be more efficient.
I have a DashDaq and I'll have to see what OBDII parameters it has that I can record, to find out if there is actually a fuel cutoff

T

Agree. Neutral if you plan on speeding up before you stop, and Drive if you would need to use the brake due to an unexpected red light or have to stop for any reason.

[unicycle]

Originally Posted by gabe1475

Agree. Neutral if you plan on speeding up before you stop, and Drive if you would need to use the brake due to an unexpected red light or have to stop for any reason.

I agree, too. Early on, I thought switching to N was a great idea. I listened to a few posters who suggested that I'd do even better keeping the car in D, and then I sat back and watched my fuelly.com readings. When they seemed to hold or even improve, I kept with the technique.

Now what I do is to accelerate 5-10 mph above my desired speed, then coast back to that speed, rinse and repeat. Called the Pulse & Glide technique, it really seems to work. And I've noticed even better mpg's when doing the pulse with a pretty heavy foot (always staying in 5th gear): rather than slowly pulsing up to the desired speed, I nearly floor it for a few seconds (to the 'ceiling' speed) and then let the car glide back to the 'floor' speed.

In March, I began driving more slowly, and that has made a significant difference, too, so it's hard for me to know which technique is working, but I must say that switching back and forth bw N and D seems to actually hurt mpg's a bit, as well as probably doing a number on your gear shifter.

[gabe1475]

For P & G, I find what helps most is using N for P&G where the bottom of the glide is greater than 40 (this will keep you in 5th gear, anything lower will result in the car shifting to 4th gear). If you are doing P&G where the lower end of your glide is less than 40 keep in drive. Here are some examples of how I pulse and glide at different posted speed limits:

Speed Limit -------------- 35 40 55
Upper MPH of P&G -------- 40 50 65
Lower MPH of P&G -------- 35 41 55
Gear Selection durring glides D -N -N

(Sorry does not line up verry well)

I was able to get 60MPG on the way home yesterday (according to scangauge and calibrated to the car already). It gets a bit more complex with several lights, but there is a huge difference in the MPGs.

What would be nice is if there was a way to bump start the smart as you would not be using any fuel during the glides (assuming your AC is off). Let me know if anyone knows any way to do this whithout using the ignition.

[pogipie]

from what i understand after reading this post......your coasting in neutral traveling at any speed.....you can put it D while moving? without damaging anything?

[TMACK]

Originally Posted by pogipie

from what i understand after reading this post......your coasting in neutral traveling at any speed.....you can put it D while moving? without damaging anything?

Yup, not a problem. Just shift from D to N and back to D. I do it all the time.

[gabe1475]

Yesterday on my way home I almost got stuck in the right lane with the person at the front not able to make the right when I saw an opportuninty to jump over so I gunned it. The car took off like a bat out of hell, and the car had a sound similar to a tuned sports car. The woman in the next lane looked at me like I had lost my mind. I don't usually drive like that, it was actually the first time I tried full throttle (did not want to try durring break in). I was able to save a few drops of fuel by not idling throught the next light as well, add that to your hypermiling techniques!