Coasting?

[pulsar]

I have only seen my 2019 G70 3.3T coast once in the 4 months I've owned it and that was for about 5 seconds. I did the 13.5 S/W upgrade about 2 weeks ago and it sounds like it may never happen again...
Enjoy,
Carguy55

I have a 2020 3.3 sport and sometimes drive in smart mode. I’ve seen the coast feature activate several times. If on a slight incline and I let off throttle some I see the coasting light come on. Not convinced this feature really adds to MPG though? Sort of like the theory of not using your air conditioner saves you gas. Mythbusters debunked that as an insignificant difference.

 

[Carguy55]

I'm always in eco mode and seldom in a hurry, so I'm a little surprised that it doesn't "coast" more often though I agree there is probably no real fuel savings unless you're driving out of the Rockies or the like.
Enjoy,
Carguy55

 

[joschneider]

I'm always in eco mode and seldom in a hurry, so I'm a little surprised that it doesn't "coast" more often though I agree there is probably no real fuel savings unless you're driving out of the Rockies or the like.
Enjoy,
Carguy55

If you were, it wouldn’t activate. It turns itself off if the grade is higher than 5% either way. I’ve had mine activate several times post 13.5 update but it’s always on a mostly flat road and doesn’t last long

 

[Carguy55]

Well, I drive on mostly flat roads here in SE Michigan and never coast...

Enjoy,
Carguy55

 

[joschneider]

Well, I drive on mostly flat roads here in SE Michigan and never coast...

Enjoy,
Carguy55

I couldn’t tell you why. But the manual does call out that it only works with + or - 5% grades

 

[Ishikaro]

I have a 2020 3.3 sport and sometimes drive in smart mode. I’ve seen the coast feature activate several times. If on a slight incline and I let off throttle some I see the coasting light come on. Not convinced this feature really adds to MPG though? Sort of like the theory of not using your air conditioner saves you gas. Mythbusters debunked that as an insignificant difference.

I can guarantee that it no longer coasts on relatively flat roads it once did (after my software update). I can also tell you that my work commute mileage went from 9.8 L/100KM (24MPG) to 10.9 L/100KM (21.6MPG) after this change.

I hope they don't try to fool me during tomorrow's drive, and if I can confirm that they deliberately neutered this feature, I am going to raise hell. You can't just remove a feature, call it an upgrade, and not tell anyone. Hell the owner's manual still says that this feature exists...

At the very least, I will ask for reimbursement for all the fuel wasted for the lifetime of the vehicle. Premium gas is REALLY expensive in Canada compared to the states. I just paid $1.51 per liter for 91 octane ($4.30/gallon), and I could be saving around 10% with coasting in my commute!

 

[danygenesis]

I've owned my car for more than a year now. I drive almost all the time in Smart mode. in the flat roads of Florida and the car coats a lot

 

[Husky]

I couldn't get my car to coast the other day, despite all the conditions being met (and after figuring out that you have to have touched the gas last, not the brakes). Although I believe this feature's value is dubious, it's still annoying that it doesn't seem to want to work.

 

[pulsar]

I couldn't get my car to coast the other day, despite all the conditions being met (and after figuring out that you have to have touched the gas last, not the brakes). Although I believe this feature's value is dubious, it's still annoying that it doesn't seem to want to work.

You have the coasting feature activated, correct? From the factory mine was not until I toggled it on.

 

[OMG70]

I couldn't get my car to coast the other day, despite all the conditions being met (and after figuring out that you have to have touched the gas last, not the brakes). Although I believe this feature's value is dubious, it's still annoying that it doesn't seem to want to work.

So immediately after updating my software, I used to coast more often, but now I have noticed that it takes a while before the car will use coasting in the morning, even on flat roads. Once i get on the freeway to work (3 miles from home), the car will start engaging it. Curious if it might have something to do with temperatures or driving behaviors and if the function "learns" in a way that tries to estimate when you would want coasting or not

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[Ishikaro]

Just came back from Genesis and here is some additional information:
- The feature was neutered as it would drastically reduce the life of the transmission and somewhere around the 6 year mark, the transmission would need to be rebuilt at a cost of approximately 14K CAD.
- Instead of the 7 conditions for activation in the first version of the software, there are now approximately 30 conditions (most of which are not visible to the driver, and not disclosed in the manual) that need to be met to trigger this feature. Essentially, there is no way to reliably trigger it by the actions of the driver (very convenient way for Genesis to maintain that it's working as intended!)
- They said if enough people complain, there will be pressure on the software manufacturer to release an update to allow the feature to trigger more often; however, the likelihood of people complaining is very low as people purchasing the car now have never experienced the eco-coasting feature as it used to be, and for many people they never bothered to turn it on in the first place when they purchased the car.
- Owners retain the option to downgrade the software on the ECU but this means foregoing all future updates and possible warranty issues upon transmission damage

I personally can play around with the drive mode and cruise control settings (randomly changing them over and over for a few minutes) and that seems to make the eco-coast work as it once used to. I duplicated this during the test drive with the technician and asked him how this can be considered 'working as intended' when none of the other 23 mystery conditions are being met but he maintained that the as far as Genesis Canada is considered, the car is working as intended and by playing around with the settings, I am probably satisfying some of the mystery conditions... again smells like a load of BS to me.

 

[joschneider]

^i just don’t understand how coasting could cause damage, let alone enough for them to say it reduces the tranny life expectancy by that much. If it’s true, I’m turning mine off completely

 

[OMG70]

^i just don’t understand how coasting could cause damage, let alone enough for them to say it reduces the tranny life expectancy by that much. If it’s true, I’m turning mine off completely

Without any research, I'm imagining slightly mismatched rotational speed between the pieces that are uncoupled. When they rejoin there is some sort of grinding that occurs. Assuming you drive only in eco, this could add up, right? What I'm thinking of is basically the worlds best manual car driver. Their clutch will last far longer than others, but inevitably will need to be replaced at some point.

A more traditional automatic than one with coasting would stay permanently coupled, right? So then there's no ability for the trans to have that grinding. Like you said, turning mine off next time I get in the car

Disclaimer: I know very little about cars and none of this is researched at all

 

[pulsar]

Without any research, I'm imagining slightly mismatched rotational speed between the pieces that are uncoupled. When they rejoin there is some sort of grinding that occurs. Assuming you drive only in eco, this could add up, right? What I'm thinking of is basically the worlds best manual car driver. Their clutch will last far longer than others, but inevitably will need to be replaced at some point.

A more traditional automatic than one with coasting would stay permanently coupled, right? So then there's no ability for the trans to have that grinding. Like you said, turning mine off next time I get in the car

Disclaimer: I know very little about cars and none of this is researched at all

I thought most of the coupling and de-coupling of power takes place with the torq convertor so we should not have metal on metal grinding? I’m sort of confused to how this wears out our transmission sooner? I have a 2020 so wonder if I already have the updated transmission software, or as soon as I update the infotainment center Genesis will make other changes to my car and not be all that transparent about it?

 

[OMG70]

I thought most of the coupling and de-coupling of power takes place with the torq convertor so we should not have metal on metal grinding? I’m sort of confused to how this wears out our transmission sooner? I have a 2020 so wonder if I already have the updated transmission software, or as soon as I update the infotainment center Genesis will make other changes to my car and not be all that transparent about it?

I'm definitely the wrong guy to ask, but I found this on a stack exchange forum

"It is fine to coast in an automatic in neutral as long as the engine is running. If you stop the engine completely and coast (as is often the case when being towed), you can damage the transmission.

The reason is that the transmission circulates fluid for lubrication and cooling, and this circulation is powered by the engine. Rotating the drive wheels (coasting or being towed) without the engine running causes transmission parts to be moving without sufficient lubrication or cooling, which will wear them out much more rapidly."

Maybe when the torque converter decouples you run into a similar issue where the lubrication in the transmission isn't happening? Like I said, all poorly informed guessing on my part. Maybe @Toddasaurus or one of the members in the car industry could lend a hand here

 

[Ishikaro]

I thought most of the coupling and de-coupling of power takes place with the torq convertor so we should not have metal on metal grinding? I’m sort of confused to how this wears out our transmission sooner? I have a 2020 so wonder if I already have the updated transmission software, or as soon as I update the infotainment center Genesis will make other changes to my car and not be all that transparent about it?

Yes, 2020 models have already been updated.

 

[Toddasaurus]

I really don't think torque converters are able to completely decouple like that. They have an element in them that allows them to directly drive the transmission; otherwise, all of the power is transmitted essentially like a fluid coupling.

Engineering Explained has a really good video explaining how torque converters work. He doesn't explain how the direct drive coupling works (though he does mention it briefly), rather just general operation of the TC.

Either our transmissions are able to decouple somewhere inside along the clutch packs, or at the transfer case. I would assume the latter of the two.

For the record, I don't know how it all works. These are just educated guesses. I haven't studied much about our transmissions other than some basic attributes of the valve body.

 

[TinsleyC]

My car doesn't have the automatic feature for coasting but on occasion I will shift to neutral while driving just to coast. I often have long runs of road between traffic lights at major intersections and the car will coast in neutral much longer than it will in drive. I do wonder if this wears anything out.

 

[Husky]

You have the coasting feature activated, correct? From the factory mine was not until I toggled it on.

Yes, it's enabled. Although it's puzzling that it won't coast when it seems that it should, I still believe it's of little value. Under what conditions would it remain in coast for any length of time (assuming it even did when it was supposed to)?
If you're going down hill, it won't be activated if it's a steep grade, but in any case you would be picking up too much speed before long and need to tap your brakes, taking you out of coast.
If you're going up hill you certainly won't be coasting.
If you're on level ground you can coast a little, assuming there's no need to speed up or slow down, but before too long drag is going to slow you down and you'll need to give it some gas, so not coasting.
I think coasting is mostly a marketing "feature", for a car whose gas mileage is on the low side compared to the competition.

 

[ECF]

Former transmission design engineer here (for off highway applications so my experience is not exactly apples to apples) though some of my former coworkers did transmission/powertrain design for OEM automanufacturers. I don't own a Genesis (though strongly considering) so I can't definitively say that they use the same hardware architecture, but on the applications I've worked there's a single speed oil pump that lubricates the transmission which is driven by the engine. So the faster the engine turns, the more lube oil goes the transmission. If Genesis does the same (which other automakers do), then when you coast and the engine gets decoupled and it's speed drops to idle (let's call it 1200 RPM) from 2400 rpm at 70-75mph (feel free to correct me if I have the wrong engine speeds listed) then lube flow to the transmission would drop by 50% but the ground speed still stays the same.

Neutral is a specific clutch engagement position where the output shaft spins but does not receive power from the torque converter. When in neutral the transmission still spins regardless of what the engine does so if the car has appreciable ground speed but little/no engine speed, the transmission can overheat due to lack of lube flow. This is the same reason why you tow FWD drive cars with the back wheels on the ground and why you tow RWD cars with the front tires on the ground (you want the wheels that aren't connected to the transmission to spin).

@Toddasaurus the feature in the torque converter (TC) you're talking about is the lockup clutch (LUC). In "converter drive" there is a speed differential between the flywheel side of the TC (impeller) and the transmission side (turbine). At low engine speed this speed differential creates torque multiplication and can help initial acceleration (TC output is slower than the engine flywheel) but at high speed this is known as convertor loss or drag (when you want the output shaft to spin as quickly as the engine but can't because of the fluid coupling). The LUC connects the impeller to the turbine to achieve a "direct drive condition" which engages (and disengages) when the TC output speed sensor hits a certain value. This makes the TC output shaft speed the same as engine flywheel. This can be seen almost like an "extra shift" but the feel may not necessarily have a pronounced feel. To try it, go into automode and let the car shift into 8th gear on it's own and keep the ground speed constant. You should see the engine RPM drop again (slightly) this is the LUC. The benefit of the mechanism is only realized at higher speeds to reduce fuel consumption so I'm not sure if the transmission software would enable LUC at anything other than 8th gear.

@TinsleyC based on the above I highly recommend you not shift into neutral when driving.