P&G (Pulse & Glide) follow-up discussion

[unicycle]

I just completed a full tank of P&G driving. This info should be considered much more relevant than my previous post, tho it wasn't way off the mark, either.

Recap:
In my earlier post (Pulse and Glide (Hypermiling trick)), I detailed (and linked) the technique and described my improved MPGs. At the time, my ScanGauge was apparently set incorrectly so that my MPGs readout was skewed too high. I was hopeful that I was getting just over 50mpg.

Subtopics to avoid here:
The other post already has an overabundance of discussion about driving techniques, the potential to piss off other drivers, courtesy, road rage, and so forth. None of that actually applies to my own commute bc I travel at odd times. Similarly, none of that discussion belongs in THIS thread. If you feel that you must comment on those topics, please create a separate thread and rant away.

Old data:
I set my SG at the most recent fillups at +13%, and this apparently led to much more accurate data (lower MPGs than before, too). For the tank that ended 3 days ago, I only used P&G for the last few gallons. Still, when I did it, I noticed a definite improvement on current MPGs -- about 5-10% increase.

New data:
MILEAGE...For the most recent tank, all of which had the benefit of P&G. I had over 47 mpg, and I think that this measurement is accurate bc it came off both the SG and from my fillup calculations (miles driven divided by fuel used). This 47 represents approximately 5% more than I had been getting recently (my avg up to this point has been 43 mpg over 25 tankfuls).
SPEED... I drive at an avg speed of about 60 mph, pulsing up to 65 and gliding back to 55.
FREQUENCY: I believe that under ideal conditions (flat terrain or a mild downhill), you need to use the technique about 2 times per mile, meaning that you use the accel pedal two times per mile. I probably used the technique an avg of once per mile since conditions (terrain, other cars, etc) didn't always allow it.

Considerations:
PSI...Not only did I use P&G+Coast, but I also had increased my tire pressure to 40 psi per tire. On the face of it, that could have accounted for ALL of the increase in MPGs. BBBUUUTTT...
A/C... this most recent tank came under the hottest weather I've driven in since I got the car, and the A/C was on about 80-90% of the time, which is much more than it had been used during the previous tanks.

Summary:
I'm going to guess that the increase in psi was obviated by the increase in A/C usage, meaning that the mileage gains were most likely due to P&G.

Findings:
I'd guess that for a smart car, P&G+Coast is worth about a 5-10% bump in mileage, depending on speed chosen, topography, and frequency of the technique.

[Bum-bling-B]

Unicycle - since it seems like we are right around the same mileage 8k-9k miles I noticed a sharp increase in mileage but that could be anything. Just a thought though- I know there's no magic # of miles on the car that makes it increase in mpg's.

This is my first tank I've ever made it to half at precisely 200 miles. Also, my P&G is more like 65MPH then down to 61MPH. Barely a P&G for the most part. I maintain with the flow of traffic too - when there is traffic. I still zip along. Seems like everyday I get stopped and someone mentions how they see me zipping around. They do use the word zip a lot and it is females that always say that. I take it for, "hey, you don't hold up traffic in that tiny car".

The other thing is I intentionally set my Scangauge to read the MPG's low. Same effect as setting your watch ahead 5 minutes. Reading lower MPG's makes me try harder for better mileage.

[jwight]

I think I'm missing the idea of P&G entirely, so I've decided to work on keeping the rpm between 2K and 3K whenever possible. For our traffic and roads, that seems to be the smart's "sweet spot", giving acceptable performance without sucking too much gas. No ScanGauge, no hypermiling techniques and the occasional urge to get on it away from a stop light, so max mpg won't happen but for me, it's a good compromise.

[unicycle]

Originally Posted by jwight

I think I'm missing the idea of P&G entirely, so I've decided to work on keeping the rpm between 2K and 3K whenever possible. For our traffic and roads, that seems to be the smart's "sweet spot"

I haven't tried gauging RPMs, but I'm told that you're right about the #s.

For P&G, you could try watching the RPMs while gently speeding up to, say, 70 and then letting off the accel pedal until you hit 60, rinse, repeat. Even without the neutral-gear glide, you should still improve MPGs.

Any idea what your mileage is with the RPMs in the 2000s?

[ASmartMan]

Howdy

As most know I've have and will try (if I ever find non E 10 gas) Hyper Mileing tricks

The 1 thing I can say is, the moment you put a SG2 or any kind of instant MPG meter in your car, you'll get better mileage.

So if you have a SG2 or what ever to measure instant MPG and plan on doing a Hyper mile test, pull it out for the test

I know it sounds strange, yet I was able to go from 44 MPG to 56 MPG by being a slave to the instant MPG reading of my trip computer.

Just a thought

ASM

[Karl Roth]

Originally Posted by unicycle

I haven't tried gauging RPMs, but I'm told that you're right about the #s.

For P&G, you could try watching the RPMs while gently speeding up to, say, 70 and then letting off the accel pedal until you hit 60, rinse, repeat. Even without the neutral-gear glide, you should still improve MPGs.

Any idea what your mileage is with the RPMs in the 2000s?

I would think keeping it in gear would help. The engine management adds fuel in neutral to keep it running and shuts it off on overrun. Have you corrected for odometer error as well?
have fun
karl

[unicycle]

Originally Posted by Karl Roth

I would think keeping it in gear would help the engine management adds fuel in neutral to keep it running and shuts it off on overrun. Have you corrected for odometer error as well?

There is some punctuation missing in that first sentence somewhere, but I think you're saying that the engine mgmt adds fuel in neutral but shuts it off in overrun. I'm not sure what 'overrun' means - is that where you're foot is off the gas when the car's in D? Anyway, the car quickly decelerates in D, even down a gentle slope, but not in N, and this seems to make up for the effect of the engine mgmt system. Turning the car OFF would save even more gas, but I'm not trying that again after learning how the brakes stop working (I nearly crashed into the trees below my driveway after an attempt of this). I certainly wouldn't advocate that on a hway (nor is it legal).

Yes, I corrected for odo error, too, by which I think you mean speedo error? I added 2 or 3 mph, and now the speed of the SG2 matches the speed on my GPS.

Originally Posted by aSmartMan

I know it sounds strange, yet I was able to go from 44 MPG to 56 MPG by being a slave to the instant MPG reading of my trip computer.

I'd love to hear some specifics from you about your driving style and tricks. As far as I know, the only way to hit 50+ mpg in the smart is to drive REAAALLLLY slowly, and I'm sure that's not what you're doing (I mean, sub-50mph). I'd say that 56 mpg is probably a result of human error. I've hit just under 418 miles on one tank. Going 56 mpg would put you at nearly 450. You'd be hitting 400 miles on a tank with one bar left. I seriously doubt that this is happening (esp'ly since you aren't using P&G or mentioning other hypermile tricks), but if it is, you'll have to fill us in on how.

[jwight]

Any idea what your mileage is with the RPMs in the 2000s?

I've just started trying to stay in that range so I'll have to do a couple of tanks and get some new numbers.

Karl, glad you mentioned odometer error. I know the speedo on our car is off by 2-3 mph (fast); I suspect the odo is off also but haven't checked against mile markers. If the odo is reading low, that will inflate the mpg numbers by some amount.

[Karl Roth]

Originally Posted by unicycle

There is some punctuation missing in that first sentence somewhere, but I think you're saying that the engine mgmt adds fuel in neutral but shuts it off in overrun. I'm not sure what 'overrun' means - is that where you're foot is off the gas when the car's in D? Anyway, the car quickly decelerates in D, even down a gentle slope, but not in N, and this seems to make up for the effect of the engine mgmt system. Turning the car OFF would save even more gas, but I'm not trying that again after learning how the brakes stop working (I nearly crashed into the trees below my driveway after an attempt of this). I certainly wouldn't advocate that on a hway (nor is it legal).

Yes, I corrected for odo error, too, by which I think you mean speedo error? I added 2 or 3 mph, and now the speed of the SG2 matches the speed on my GPS.


I'd love to hear some specifics from you about your driving style and tricks. As far as I know, the only way to hit 50+ mpg in the smart is to drive REAAALLLLY slowly, and I'm sure that's not what you're doing (I mean, sub-50mph). I'd say that 56 mpg is probably a result of human error. I've hit just under 418 miles on one tank. Going 56 mpg would put you at nearly 450. You'd be hitting 400 miles on a tank with one bar left. I seriously doubt that this is happening (esp'ly since you aren't using P&G or mentioning other hypermile tricks), but if it is, you'll have to fill us in on how.

Overun, fancy way of saying the driver has lifted foot from throttle. Stay home save more gas. Trick of the day
karl

[ASmartMan]

unicycle

I'm a 450 owner and all the details are here The Final Chapter Has Begun
, the biggest trick was under 45 Mph and shifting up as fast as the MB computer would allow, all back roads

I became a member of the 450 Miles per tank club with that test and this fall (cool enough so AC is not needed) I may try for a 500 mile tank (seeing it only took 8.1 gal to refill)