Hyper Milage Driving Techniques, Tips, Theories??????

[AudiVWguy]

Hey Everybody,
Just thinking about this today, and was thinking about all the in town driving I have been doing lately. I thought it was about time to start a thread about ways of driving to maximize the fuel consumption on the VW Diesel. I do a lot of driving in the 40-45 mph streets with plenty of stop lights.
So, what I'm having trouble understanding is acceleration techniques for the diesel. One one hand, every engine revolution is an injection of fuel into the engine. But this is also relative to how far the accelerator pedal is pressed, farther down--more fuel in.
I was just trying to get beyond the mechanical stuff, and work on adjusting the nut behind the wheel.

Acceleration    Hard or soft?

Engine Breaking or neutral (Idle) up to a stop sign.

Engine off at long lights?

How much drag is the alternator at night?

I'm sure everybody's has theories, so lets put our collective heads together and see what kind of trouble we can get into now...... :shock:

[burn_your_money]

I find that the slower I accelerate the better my mileage is. Especially on the highway.

I usually downshift to a stop, but it depends on how far away I am from a stop light. I try and time it so that I don't actually have to stop.

I never shut the engine off unless there is something like a train. Idling uses very little fuel so I figure it's not worth the extra wear and tear

When I am on the highway I limit my speed by the RPM gauge, not the speedo.

[jtanguay]

in most cases the injection quantity at lower rpm to produce more torque requires less fuel than higher rpm to produce more HP.  best part about diesels is that they're not like gassers which get fouled plugs when you lug the engine.  so make use of the lower rpm torque.

best fuel miser practice IMO is to always look ahead.  i can't help myself but laugh when someone passes me to speed up to the red light  :roll: not only do they needlessly waste gas, but they also wear down their brake pads.  i bet these people complain the most about fuel prices  :lol: sometimes i get the urge to drive like that, but its very seldom.

for acceleration, you need to learn the car, and know how much pedal you can give.  if the car isn't accelerating faster when you put the pedal down further, then its wasting fuel.  i know the TDI engines will actually stop injecting fuel if you're coasting to save fuel.  i think that the IDI governor spring will do slightly the same, but still inject a small amount of fuel.  if there was a way to completely stop injecting fuel upon deceleration/coasting, that would be very beneficial.

a neat way to make a diesel hybrid IMO would be to have large capacitor banks to store acceleration energy and drive a small electric motor.  thats one way to recoup idling losses...  but thats getting a little more complicated.

[subsonic]

If you can drive in the best Torque range of the engine, that seems to work very well. Lower end of the tq range in the highest gear it will turn.
At idle the diesel burns next to nothing.  Disregarding driving styles about down shifting etc, you will save more fuel by coasting in neutral. Long down hill, run it in neutral.

As far as accelerating, I try to get up through the gears and up to my cruising speeds.  Don't need to wind em out, but I am not going to crawl up to speed either. Run a tire size that will get you the best rpm at your desired cruising speed, add a bit more air to them.
Get the junk out of your car. if you have to haul 50 pounds less junk, it will help.

[AudiVWguy]

Does anybody have a consistent daily commute to experiment with different driving techniques?

[drrtybyl]

The comments about coasting and slow accel are spot-on.  I've found that slightly over-inflated tires also help improve coasting efficiency.  Braking while coasting up to lights also usually makes it possible to keep moving at 15-20mph through the intersection without ever stopping.

[DCC]

Just a few tips:

- Mild driving (obvious)  
- Gentle acceleration (you can still cruise at reasonable speeds and get low comsumption)
- Closed windows
- Turn off electric gizmos when not needed (i.e. rear window heating)
- Wheels with right pressures
- Don't step on it when going uphill, just let 'er go a bit.. you'll recover speed when going downhill.  :wink:
- Low revs (Use the torque, Luke!).

And here's the best tip:

ALWAYS look ahead. Braking is your enemy, so try to anticipate to traffic... it's always better to slow down and roll slowly till the light changes to green than getting to a full stop. Same with overtaking and driving on highways.

[burn_your_money]

Does anybody have a consistent daily commute to experiment with different driving techniques?

I drive the exact same way to and from work every day, however the weekends would throw everything off.

I find that keeping your cruising RPMs up, rather then as low as you can go without lugging the motor saves about 100kms a tank.

[Vincent Waldon]

When I am on the highway I limit my speed by the RPM gauge, not the speedo.

And how does the OPP feel about this approach?! ;-)

[burn_your_money]

And how does the OPP feel about this approach?! ;-)

No complaints yet

It actually keeps me to 110 instead of 120+ because I try and stay at or below 3000

[OmnibusX]

I did a test last year in connection with a jobb i did, driving Wideload car for 2 trucks down to Oslo (Norwegian capital)

 

The trip it 900km one way. on the way down there i used 45l diesel, the same as i always use every 10km, and i always drive like i stole the car



But on the return with this big thing on the car i used 56l diesel. so in my experiens you realy need to work hard to get this engin to use mutch over 0.5l on 10km

[AudiVWguy]

I've applying all the techniques and it really slowed me down that much.
One thing interesting that I noticed is about rpm's and shifting. I've been accelerating to 3K and shifting, Throttle about 65-70%. This has been working out well, keeping up with traffic flow. One gear higher than I normally have used in the past. (45 mph 2K in 5th)
One thing i tried that has some potential. When you are accelerating through 2nd gear, rev to 3500 then shift into 4th. This puts me at 2K in 4th gear. Now I'm in cruz mode and if traffic allows, I'll move to 5th. This moves all the fuel used in third out of the equation. The trade off is revving 2nd to 3500. The time from 3K to 35K is a little over a second. It feels weird to make that shift, but it works pretty smooth. Of course this idea won't work if there's a stop sign/stop light every block.
I encourage others to try this technique and give me some feedback.
Cheers,
-JB

[8v-of-fury]

One thing i tried that has some potential. When you are accelerating through 2nd gear, rev to 3500 then shift into 4th. This puts me at 2K in 4th gear. Now I'm in cruz mode and if traffic allows, I'll move to 5th. This moves all the fuel used in third out of the equation. The trade off is revving 2nd to 3500. The time from 3K to 35K is a little over a second. It feels weird to make that shift, but it works pretty smooth. Of course this idea won't work if there's a stop sign/stop light every block.
I encourage others to try this technique and give me some feedback.
Cheers,
-JB

I have tried this with my 1.7 it works well.. Assuming you dont want to accelerate anymore when you reach 4th cuz its a gasser lol. But 2500 in a diesel puts it close to max torque, NICE.