Driver Profile Selection - Coasting Function

Quote:

---

Originally Posted by tonymy01

The N gear uses fuel though (as in, for the engine to run, it runs at idle in N, you can see the MFD shows litres/HR on the instantaneous view), the coasting I was referring to was in gear,foot off throttle, the engine shuts off fuel entirely (as the engine is being kept rotated by the drivetrain).

---

That's how my manual works. In neutral it uses .5L/hour with aircon off and .7L/hour with aircon on. When lifting off in gear it shows 0L/100km and feels like it's going to roll on forever.

btw The other day my touchscreen showed 227km travelled in 2.53h at 79km/h with 980km range and average 4.5L/100km. Just typical country driving with other traffic at speed limits. I reckon that's pretty good for a petrol engine. It makes me wonder if it could ever do 1200km on a tank full like the readout predicts.

The only way I can imagine this works given the engine has quite high compression is that it somehow opens the exhaust valves early to reduce the compression during the compression stroke.

The way I get the car to roll further is foot off the accelerator and push the gear stick into s mode. It will hold the gear box into higher gear and will not down shift so soon.

Quote:

---

Originally Posted by Mountainman

That's how my manual works. In neutral it uses .5L/hour with aircon off and .7L/hour with aircon on. When lifting off in gear it shows 0L/100km and feels like it's going to roll on forever.

btw The other day my touchscreen showed 227km travelled in 2.53h at 79km/h with 980km range and average 4.5L/100km. Just typical country driving with other traffic at speed limits. I reckon that's pretty good for a petrol engine. It makes me wonder if it could ever do 1200km on a tank full like the readout predicts.

---

wow, impressive!
i hope mine gets low soon after run-in, 500km so far, 28km avg and 8.4L/100km.
keep it up!

noticed sometimes when im coasting downhill at 70-80km/h, there is no 'eco' icon on MFD, and engine rev is about 3k, consumption was showing 0L/100km. so why it keeps rev up instead of like coasting when rev is under 1k?

Actually DSGs have had coast available for quite a while. Depending on the attitude of the car, it will also hold a gear to help you on a descent.

Coasting in a standard manual is not something looked on too favourably. If you "dead stick" (i.e. put the transmission in neutral without the vehicle being at a standstill), it would be an instant fail in a driving test, and would not be looked on favourably by an insurer either.

Trying to re-engage the transmission after coasting can also place you at risk. There is a huge difference between an automated manual doing this and the driver doing this.

My Father had a Rover 90 and he used to change gear, once mobile, without disengaging the clutch. Was that the big round knob near the gear stick?

Quote:

---

Originally Posted by Idle

So what's new? I had a 1950's Rover with selectable freewheel — which also made clutchless changes a doddle.

Plus in the 1940's lived at the top of a long hill.

My 1923 Dodge would roll about a mile and a half with the motor turned off and went faster — and ever so much smoother — than it could under power (alas, rolling in "angel gear" is now banned...)

---

Quote:

---

Originally Posted by brimway

My Father had a Rover 90 and he used to change gear, once mobile, without disengaging the clutch. Was that the big round knob near the gear stick?

---

Yes — it was a Rover feature for many years.

currently the coasting function is only active in ECO MODE, I want to enable coasting function, with the engine in Normal Mode, does anyone know that can be done.
cheers Neil

Quote:

---

Originally Posted by wai

Actually DSGs have had coast available for quite a while. Depending on the attitude of the car, it will also hold a gear to help you on a descent.

Coasting in a standard manual is not something looked on too favourably. If you "dead stick" (i.e. put the transmission in neutral without the vehicle being at a standstill), it would be an instant fail in a driving test, and would not be looked on favourably by an insurer either.

Trying to re-engage the transmission after coasting can also place you at risk. There is a huge difference between an automated manual doing this and the driver doing this.

---

Yes, DSG and other more recent automatic gearboxes (e.g. ZF) have had this feature for a while. Rather than the gearbox changing up to the highest gear possible (i.e. to keep the revs as low as possible like old slushmatics do) when you take your foot off the accelerator, these boxes change down so the car "coasts" as if the engine is not there, keeping the revs higher. The ECU shuts off the fuel to the engine so the only thing turning the engine is effectively the momentum of the car (from the drivetrain). Similar thing to "engine braking" which manual drivers were taught to do on downhill bits so that your car was more stable and your brakes didn't get a beating (albeit done for reasons other than economy).

You can do it with a manual and it definitely does not involve putting it in neutral which, as you said, is very bad practice and if someone's doing that to save fuel it just shows that they don't know how their car works. As someone mentioned before, neutral will return the engine to idle speed and as there is nothing else keeping the engine turning it will start using fuel again. The fuel cut off in this manner is something that has been done for many years and if you look at old car brochures (e.g. E34 BMW of the late 80s) the feature was sometimes called "fuel cut off on the overrun".

I am really looking forward to trying all this and seeing what difference it make in economy...still 2.5 months to go!