How do you Pulse & Glide your diesel vehicle ?

[JacobAziza]

yeah, I've had quite a few ignition switch failures - and that was before I learned about P&G.
Plus there is the risk of accidentally locking steering wheel, and the inconvenience of having to reach over.
So I put a kill switch and remote start on my gear shift lever.

I don't imagine it could be good for a turbo though, and it is totally dependent on roads, traffic, aerodynamics, and more.

My point wasn't that it would work for everyone, just that it can work in theory for a diesel, even though there are no pumping losses due to the lack of throttle plate.

[So_SiMpLe_]

I see with the on board computer with my 1.4 TDI engine that if you are on a plain straight road from 35 to 45 mph for example is better if you just press gently the throtle, if you do it hard you'll take less 1/3 of the time but waste 4 to 5 times the fuel.

[Small4Seater]

But remember that the faster you get up to speed, the more time you will spend where the engine is efficient (but accelerate too fast and some engines go into "sports mode" and are even less efficient)

My 1.4 diesel is very inefficient when accelerating, so I try to keep acceleration as brief as possible.

[So_SiMpLe_]

When you go at constant speed at 80kph, with the 1.4tdi I can get about 3,6l/100km, while accelerating I get about 5,5 or so, if smoothly and plain straight raos of course.

[MaxHedrm]

The question I have for you P&Gers is how much variation is there in your speed?

My concern is that while you may be saving yourself a few bucks in fuel, you could be causing more consumption overall by interfering with traffic patterns. Not to mention the safety issue of slowing with little warning to those behind you after accelerating away from them. As little attention as people pay on the road these days you are just begging to be rearended. And speaking of attention, I'd rather you be putting all the attention you are paying to shutting things down and starting things to your actual surroundings ... though this is probably a silly concern, since it seems you guys are probably more attentive than 98% of the drivers on the road, it's just something that comes to mind.

[savefuel]

I average about 15-20% EOC with my VW GOLF TDI 1.9. P&G mainly depends on road topography, weather conditions, time of day (day/night) and mandatory speed reductions (approaching a speed limit).
The key is to manage gliding in neutral, gliding with gear engaged but foot off the accelerator or engine off coasting (EOC). This is a constant decision making progress with adds to the fun of hypermiling! Driving a turbo, I allow the engine to stabilize on idle RPM prior shutting it off. The engine reengagement is being done by applying a suitable gear while the car is still coasting and release the clutch. I only do P&G on slight downhills with speed variations of less than 15 mph (eg. 60 to 48, acc. to 60 ...). Of course You get the best results on daily commutes!
A nicely maintained 1.9 VW GOLF TDI (vehicle weighs in at 2900 lbs with driver) delivers 50/55 mpg w/o P&G at 50/55 mph.
With P&G the mileage can be boosted by another 10/15 mpg (also depending on traffic and topography).
And we're talking of US-Gallons here, of course.
(Increase the USG mileage by 20% to get IMPG mileage)

[Arragonis]

I don't P&G in traffic or if anyone is following closely. If they are tailgating then sod them they can go my pace or go past.

SoSimple - try this.

a) On your flat road reset the average and then cruise at your 35-45.

b) Then repeat pulsing to 45 and letting the speed drop to 35 and repeating.

c) Then repeat b with higher tyre pressures.

If I do these in my 1.9 TDI then I will get the best result on the computer with C every time. The problem as Euromodder pointed out is that if I do this for a full tank when I refill I see no improvement over just driving gently. My last tank had no trip with an average below 55 but the overall tank ended up at 50 which is more or less where the previous one was without P&G.

[Piwoslaw]

Originally Posted by MaxHedrm

The question I have for you P&Gers is how much variation is there in your speed?

For me about 20km/h between min and max, but only if I am more or less alone. As traffic gets tighter the difference drops to 15 or 10km/h, below that I'll probably start driving in gear, but coasting whenever possible (before intersections, for example). Usually a variation of 10km/h at speeds above 60km/h won't make much of a difference to anyone following me at a reasonable distance. If someone starts tailgating then I gradually slow down to reduce chance of injury/damage.

[JacobAziza]

When I used to drive steady, it was at 45mph.

Averaged over 7 tanks I got 26.4MPG after my last mod, (but before I began P&G)

I then began P&G.
Averaged over 8 tanks, my average has been 28.97mpg

I experimented with different speed ranges, and settled on 45mph to 55mph and back. On a flat road it takes about 5 seconds to accelerate from 45 to 55, and about 15 seconds to coast back down, so the engine is off 3/4 of the time.
Averaged over the most recent 5 tanks (after settling on a method) my MPG has been 29.65mpg

And since the minimum P&G speed was my old steady state speed, I am actually averaging a higher overall speed for a 3.25mpg gain.

Whether steady or pulsed, I am always in the slow lane, and I have a very large, very orange truck - most people see that I am slow moving, and go around on their own.
For those that get close enough to read them, my bumper stickers let them know that I am going slow on purpose, and encourage them to pass.
When I see someone coming up behind me fast (in my super wide rear view mirror), I turn on my hazards to make absolutely sure they notice me well in advance.

[WayneD]

Originally Posted by UFO

That's exactly how to P&G a diesel, as it has no throttle and it's most efficient at the torque peak, usually around 2000 rpm.

.

That's interesting!
over here in England I own a Ford Maverick 2.7ltr Diesel 4X4, it's red line is 4500 - 6000 and I have found if I drive at between 2300-2500 on motorways it gives me a speed of 56 mph and a fuel economy of 42 mpg (if there is no head wind), or around 37/38 mpg with winds which is actualy better than my old small car that had a 1.2 litre petrol engine in it.
around the city as long as I keep my revs between 1300 and 1500 ( approx 30mph) I can get between 28 and 30 mpg if there are no hills