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2016 Kia Optima LX 1.6T
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Hey y'all. I have a 2016 Optima and I had a question about using ECO mode. When I first got the car, from what I read in the manual and some other people's experiences online I thought it was a good idea to drive in ECO mode when I'm in stop-and-go traffic, going around the city not too fast and hitting red lights, and other situations when I don't need a whole lot of power/acceleration and want better gas mileage. SPORT mode for when I need to zip around or get up to speed quickly, NORMAL for the in-betweens and everything else.

I went to the dealership to get my car just generally checked out (they said it's in "immaculate" condition; I got lucky with this car I guess) and mentioned these driving habits. The guy there told me that unless I want to destroy my clutch I shouldn't drive everywhere in ECO and that I should only use ECO mode when I'm driving at a constant speed and not changing speeds very often—basically the same conditions, he said, that you'd be using cruise control (basically never in the Seattle area). I might be misunderstanding something, but this seems to go against pretty much everything else I've heard about ECO mode. Was he the one mistaken? Or is there just something I'm missing here?

Any insight on this?
 

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The 3 modes all do the same thing, adjust the shift points based on pedal pressure, as normal. Wear is the same regardless, fuel efficiency is what will vary among the 3. I call BS on what the stealership said.
 

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2012 Black SX Prem. & Tech.
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I thought the Kias were known for having robust transmissions.

They wouldn't have that reputation if the dealership was correct.

You'll come to learn not to trust anything the dealership says. The people working there have no incentive to learn how cars work. They just learn how to say things to get people to buy cars.
 

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Ok, here is why Sport mode saves your clutch, and Eco burns your clutch. Sport will get less MPG. Eco will get better MPG. The way it works. Need to explain this so everyone can understand. So, let's say you have a 10 speed bicycle. The front chain gear attached to the pedal crank has two spring loaded friction plates with sand paper in between. When you use the bicycle in 1st through 3rd gears, you can never pedal hard enough to make the two friction plates slip, so it just feels like a normal gear set, no slippage. When I tell you to put the bicycle in 10th gear from a stop, on an uphill, and pedal hard enough to get moving and continue up the hill, you will be standing on the pedals to get the bike moving. Because the friction plates only have so much friction between them (pretend there are 2 dinner plates with sand paper on them for grip, with a spring pushing the two plates together), when you try to pedal up the hill in 10th gear, the pressure is not great enough between the plates and this causes them to lose grip and slip. The sand paper between the plates begins to wear away, they slip and wear, but you are able to accelerate the bicycle and begin moving up the hill. Now, when I tell you to go up the same hill, but this time do it in 1st gear on the bicycle, it is much easier, and the two pressure plates never slip, and therefore never wear out the sand paper between them.
So, same goes for when you are talking about your car transmission. If you do all the high-strain stuff in 1st or 2nd gear, the friction on the transmission or clutches is lower because the gear ration is easier. If you are in Eco mode, the "bicycle" is in something closer to 10th gear on a bicycle. Harder to pull hills, harder to take off, more pressure between the sand paper plates, the plates will slip more, the sand paper will wear out faster, and you will need a new clutch pack sooner. This is more important on DCT transmissions, as a regular old-school automatics have a fluid driven torque converter as opposed to a dual clutch system (clutch being the two sand-paper covered plates pressing against each other).
So, with that said. When on a road trip on the highway, no notable traffic, use Eco. Normal driving, use regular mode. When in stop and go, use Sport mode. When driving aggressively, use Sport mode. The goal here is to minimize the clutches pressing together, slipping against each other, and wearing out. The burning friction is much higher if the engagement is being done in a higher gear (like trying to accelerate the bicycle in 10th gear).
 

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Difference between a bicycle and car A/T, is that the bicycle will stay locked in that gear and will never move, while the car transmission, when a load is detected it will shift to the appropriate gear, even in ECO mode. Now, in the crappy DCT, as they are computer controlled, would believe that they work the same, whether the car has 160HP or 400HP, in ECO, Sport or any other mode.
 

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Yeah I feel like, for the analogy to work, you need to have the same power output, which would result in the slippage you describe in the analogy to sandpaper bike.

But for the car, I think the analogy doesn't apply, because the power output is NOT the same, you get less power to avoid slippage, and so if you demand more power, the transmission will just downshift.

I think that's the key difference: with our cars in ECO, the gears are held longer before downshift because the car will produce lower power output as expected. So instead of slipping to get more power, it just gives you less power and you are OK with that because it's in ECO and you realize it's just in a higher gear with lower power, because you don't need the power.
 

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2016 Kia Optima 1.6T LX
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Well, to dig deeper, my analogy is correct, but, the slippage only occurs when the clutches are disengaging and then re-ingaging. I feel it most when putting around slowly in a parking lot, or starting and stopping in stop and go traffic. I guess you have to identify when the clutch system is engaging and disengaging the most. That is when you want to use Sport mode. Once the clutches are engaged, they probably won't slip in any mode unless they are truly worn out. It is that transition time. A good example, put car in Eco, slow to about 3 mph, maybe even 1 or 2 mph. Because you didn't stop, and you are in Eco mode, the transmission will likely stay in 2nd gear instead of 1st gear. When you accelerate, the clutches will be scuffing more as they transition from disengaged to engaged. As opposed to.... doing the same in Sport mode, which will likely put the transmission into 1st gear before you slow to 3mph. Now accelerate again. The scuffing or friction to the clutches is less because it is easier to get the car moving in 1st gear as opposed to 2nd gear....
 

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the slippage only occurs when the clutches are disengaging and then re-ingaging.
Would you say, the clutches experience the same wear under low load or high load?

Would ECO mode put less torque on the clutches because you are in a higher gear, with less power output?

Under sport, the clutches get more wear because there is more torque or power output that the clutches must overcome.

This is an interesting topic. Is there any literature or analysis about what makes clutches wear out in transmissions? I thought it was mostly from how much torque you are putting out when shifting, so that staying in higher gears longer babies the clutches and makes them last longer when you use ECO?

So with ECO, you shift less frequently. Wouldn't that be a factor? In sport, you shift more often, so you wear the clutches faster. I feel like the torque difference, and the difference in number of shifts, both favor ECO to give you longer transmission life?
 

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"So with ECO, you shift less frequently." ECO shifts more frequently IMO. When I'm in town with ECO on I'm in 6th gear sometimes. An engine and transmission are lugging in 6th gear going 40 MPH. I might also add, My wife (a Karen) hates ECO mode also :D
 

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I just sense ECO needs more pedal pressure to downshift (when trying to accelerate once in highest or higher gear) compared to ECO Off, which needs very little pedal pressure to downshift.

The other rather apparent difference is the lower RPM shift points of ECO, trying to save gas by not revving engine too much for accelerations purposes. In general, I'm like a lot of others above, don't like ECO mostly because of pedal pressure needed to downshift to accelerate, so I leave it off.

Now previous owner (close friend) drove it in ECO for 186,300 mostly highway miles before handing the car over to me. At nearly 209,000 now and have been using it in ECO Off. Fuel efficiency does drop a small amount too in ECO Off mode yet it is a very fair tradeoff, I think.
 
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