Pulse and Glide: Geo Metro

[Daox]

I do what most would call aggressive P&G. I do it constantly pretty much everywhere I go. General rule I use is 5 mph over the limit to 5 mph under the limit. When my car was in near stock form this got me in the high 50s for mileage, or roughly 200% EPA.

For metering acceleration, I use LOD on the scangauge and keep it around 75%. This translates to very low throttle input at low rpms.

[ESmooth]

Same for me as Daox. I regularly P&G on the freeway with a 5-7 MPH window, ideally behind a truck to get some drafting effects and not have someone riding my bumper. With a consistent average speed, the cars behind me dont seem to be too affected by my changes as long as they keep a steady speed themselves. When Im behind a truck, people seem to expect slower speeds and maybe some more dramtic speed changes or just go around as soon as they can.

As long as you arent doing big changes in speed, P&G is effective even at highway speeds. Its most effective if you are adding in engine off coasting at lower speeds with little to no traffic.

[SVOboy]

I've found that at highway speeds, even when P&G can be effective, DWL is more so. This is just anecdotal however, has anyone tried to do a decent comparison?

[fairdinkumfrankies]

ESmooth and Daox sum up what I have done. I am very new to this also and I don't have an opportunity to drive under 40mph as I drive mostly highway. My bests results were slow lane, drafting, killing the ignition on long hills (when no one is following closely), keeping the air off, and never exceeding 65mph.

[ESmooth]

My results are far better with P&G than with DWL, even at painfully slow speeds on the freeway that i found to be almost dangerous. With the combination of accelerating at known optimal BSFC levels and high tire pressures/aero mods/drafting for improved glides I am easily able to beat 40MPG on trips where DWL was in the mid-high 30s at best. My personal best was 54mpg on a trip while P&G drafting a truck at 50-55mph.

[SVOboy]

I suppose I should also note that my experiences with P&G are different because of honda's lean-burn technology, which to a certain degree makes a constant state of driving in lean-burn very advantageous for fuel economy when compared to the fuel spent during the pulse portion of P&G. I should try it out at higher speeds in another vehicle sometime...

[ESmooth]

Very true, I dont have lean burn in my EX so I cant take advantage of that feature making P&G the better choice.

[MetroMPG]

MadisonMPG - the slower the speeds at which you P&G, the more advantageous that technique is, vs. driving with load (DWL).

I'll echo what others have said: P&G gives better results than DWL. But I don't do P&G much any more in normal highway driving (a repeated P&G routine, that is) because it's kind of a pain in the butt (to me), and it makes sense to me that it's harder on the car.

Skylark: you're right that pulsing briskly will show worse instant MPG than pulsing slowly. But the brisk, low MPG pulse is more efficient when it operates the engine in its best BSFC zone. You'll end up using less fuel to reach a given target pulse speed because you spend less time accelerating.

Of course, this mostly applies to cars with manual transmissions, where the driver has more control over engine load (through gear choice, no torque converter).

[skyl4rk]

Thats the theory that I had heard as well, but on long, comparable runs, I could achieve better mpg with a very light acceleration compared to a moderately brisk acceleration. My Versa has an odd engine, a Renault design, I believe. It seems to like higher rpms and light acceleration.