Hey guys, I have recently been driving in "reduced" engine mode, or "eco", or "slippery" depending on which model year of C43 you have. The point is that the engine is set to reduced. I never thought I would say this but the car feels noticeably more relaxed on upshifts and it also downshifts quite softly compared to moderate and dynamic engine mode. I also just love the overall "smoothness" of the car and it's still fast enough for normal day to day driving.

I know that it's probably not healthy for the engine to cold start and then switch to dynamic/sport+ mode right away, since the car needs to warm up and all. If someone can confirm this actually, because I couldn't find anything in the manual mentioning that there are any risks with switching to dynamic/sport+ mode right after a cold start, but it just makes sense to me to not do this. However, is it okay for me to switch to reduced/eco mode right after a cold start? This reduces engine power but it also causes the car to shift at a lower rpm as well. I'm not sure if it's better to just leave the car in its default moderate engine mode until it warms up and then switching to reduced mode. I would like to switch to reduced right off the bat though, since I really do enjoy the ride quality in that mode.

 

As long as you aren't lugging the engine, you should be fine. But definitely don't beat on your engine when cold in Sport+.

 

I know that the car won't be aggressive in Sport+ until it is warm (at least mine won't be).

 

You are way overthinking this. If they didn't want you to select certain modes right away, they would lock them out until conditions are met. Key is to let things reach operating temperature before you get on it. In S+, the transmission program tends to keep rpm higher, so you are more likely to be less gentle while its warming up, but you could always manually upshift. When I leave my house, I generally head straight for the highway. It's less than 2 minutes away. As soon as I'm on the onramp I put my C63S in I*, which I've setup mostly like S+, so engine in Dynamic, but with the suspension in Sport and the transmission in manual mode and I simply take it easy, upshifting early etc. until everything is warmed up.

As for Slippery mode specifically, it's an even gentler mode than Comfort and if the roads are actually slippery, what would be the point of not using it right away? It reduces and flattens torque and power and keeps the shifts smoother to minimize sudden changes in tractive force that could cause the tires to lose traction in slippery conditions. I'm not entirely sure, though, why it's even there in the C43 given it has AWD. I have yet to really see a need for it even with the more powerful C63S and only RWD. Comfort mode with proper throttle modulation and short shifting is just fine. I suppose one could use Slippery mode in dry conditions, I guess what you have at that point is a stiffer riding C300. Are you sure you bought the right car for yourself?

 

After setting it in I* while getting into the highway - do you floor it and just change the gears earlier or you are still relaxed with the gas pedal? I'm asking as I have similar situation (5 mins instead of 2 to enter the highway, so still not 70 Celsius degrees most of the times), but as I live in Switzerland, entering the highway is one of those rare moments where I can really enjoy the power of the car .

 

Yeah, I like the "dual personality" to actually be dual haha. I also like the reduced engine that slippery mode puts the car in since it smoothens everything out. I do like the sportiness, but I also like comfort. I would go for an equivalent E class but that is more $$ than I want to spend. I do get on the car hard at times though, so a C300 wouldn't have suited me.

 

Relaxed on the gas pedal, unless I have a short merge window, however with 500+ HP and 500+ lb ft of torque, I rarely need to floor it to get ahead . Part of warming up the car is to not put full load on the engine while it's cold, so no wide open throttle until things have reached operating temperature.

Yes, I get the dual personality aspect, but Slippery/Reduced mode is a reduced power mode. That makes sense in a powerful car, especially RWD, so it's less likely to wanna kill you in adverse weather conditions, but it's not a mode that's meant to be used for normal driving in dry conditions. A car with less than 400 HP really doesn't need a reduced power mode. There are some cars like Ferraris where the wet mode is also meant for slow city driving and traffic, but then Ferraris don't have a Comfort mode, other than the bumpy road suspension mode. The normal drive mode for a Ferrari is Sport. AMGs have the Comfort mode for normal driving and then Sport, Sport+ and Race for different levels of sporty/dynamic driving. My opinion has always been that if one doesn't like the engine and transmission characteristics in the normal mode, then the car isn't right for them. It's one reason I moved on to AMG from Audi Sport, because Audi's normal mode (Auto) is becoming more and more the new Eco mode with a sluggish and frustrating response. I have definitely considered using Slippery mode occasionally in the city or perhaps even in stop&go traffic, but if it ends up being the primary mode one drives in, then I really think it's the wrong car. I think for what you are looking for, Audi would be the better fit. Even the RS models. They are softer and more relaxed for daily driving.

 

I'm not sure if the transmission in your C63 is different, but 1st gear in the 9spd auto on the C43 is VERY rough. It's got the shortest gear ratio I have ever seen, shorter than supercars and much sportier cars. I hate that it lunges forward unless I CAREFULLY ease it in 1st gear off the line, which is bothersome to have to do every time. Reduced engine mode seems to help with this a lot. Again, I like this reduced power mode mainly for smoothness. If the 1st gear wasn't utter crap in the C43 and the automatic down-shift into 1st gear wasn't also super unrefined, then I would not need to use reduced engine mode either. It's not because the car is too fast, it's its unrefined characteristics.

 

They are not the exact same transmissions as the C63 has a wet clutch in place of the torque converter, but they are the same in terms of gear ratios. The coupes actually have even shorter gearing due to a shorter final drive. The C43 sedan appears to have the same final drive ratio as my C63S Coupe of 3.07:1 and a first gear ratio of 5.35:1. So exactly the same overall ratio. Obviously the programming is different and the engine characteristics are different. Yes, it's a short gear, but that's not really the problem. I'm aware of the complaints about the C43 transmission's shift quality. There've been many discussions on this topic, and I've largely concluded that it has to do with the fixed torque split AWD system of the C43, and perhaps a not quite harmonized transmission programming. The C63 has the advantage that it only powers the rear wheels, so things like differential binding is not an issue. The fixed torque split essentially acts like a semi locked differential at all times. Other AWD systems have variable torque splits. 4Matic+ for example sends 100% to the rear under normal conditions, so it's essentially RWD until lack of rear wheel traction causes it to send power to the front wheels. Audi Quattro uses a torque sensing center differential that changes its ratio based on available traction, and in the A3 platform it uses a Haldex system that primarily drives the front wheels and engages the rear wheels when needed. Similar to 4Matic+, but the wrong way around. The C43 has a certain characteristics based on its mechanical underpinnings, and if you don't like it and have to revert to a driving mode that's only meant for limited situations in order to be happy, then I don't think the car is a good fit. Just my 2 cents.

 

Let's just say that I have to do that to compensate for the shortcoming of this car's transmission, unfortunately. Everything else about it is just perfect though, so I wouldn't say that the car isn't a good fit just because of that one transmission issue, and that issue is not anything to do with what I prefer, it's actually a fault on Mercedes part from how I see it.

 

Sorry to resurrect this oldie, but I’ve been wondering if reduced or comfort is best for mpg when highway traveling at 70 to 80 mph? When driving around town, for example, I’ve noticed that mpg is not significantly different between engine modes, while feathering the gas pedal. My experience is that a super light gas pedal touch calms the beast when launching. Also, I find that using the HOLD function to be a terrific way to launch smoothly, no matter the mode.

 

At those speeds, I highly doubt the driving mode will make much difference. What will greatly impact MPG is speed. A constant 60 mph vs. 80 mpg will have a big impact on MPG. That said, I will venture a guess that few people who bought a c43 will seek a higher MPG in lieu of having fun with the car.

 

I get that the transmission in C43 have its shortcomings as superswiss pointed those out. However, it would be nice to be able to come to a complete stop in 2nd gear. It's really the shift from 2nd into 1st gear that is very abrupt. A lot of cars can come to a complete stop and remain in 2nd gear. The E350 can do it with its transmission I am certain of that, and I think the pre-facelift C43 was able to remain in 2nd gear at a stop as well. It's very unfortunate that there is no way to do that with the facelift C43.

 

There is a good reason the car has a transmission and oil temp gauge that start out blue in color and then turn white -- everything mechanical in this world needs to come up to operating temperature before being stressed (especially metals) or it reduces the lifespan of the material, and can cause pre-mature failures. The smartest thing to do is drive the car responsibly until the temp indicators are both white in color - it makes no difference which mode you're in - it's all about the force applied to the gas pedal....once things are warm, anything goes.

 

So this is interesting actually. When I first got my C63 it would always downshift to 1st before coming to a complete stop, and that was indeed very jerky, but after a few thousand miles it stopped doing that all of a sudden and now it no longer downshifts into 1st until the car has come to a complete stop. I have no idea what I did, but it clearly is something that it adapted to. It doesn't start in 2nd gear as the PFL did, which I never liked, but if I just do a brief stop it remains in 2nd. It even does this in manual mode now. I can creep around and keep it in 2nd unless I come to a complete stop for long enough. So this has something to do with the transmission properly adapting to your driving style. I've said this before, I only let the transmission shift automatically in Comfort mode around town or just cruising on the highway. I manually shift in all other modes. I have this theory that hauling around in the different modes, and driving in S+ around town will result in a more aggressive adaptation of the transmission, because it can never really figure out how you really wanna drive. My transmission basically only ever learned my casual driving style and I never mix it with my dynamic driving style.

 

Wait, so can you actually stay in 2nd gear at a complete stop? I'm assuming no. What I wish for is that the transmission can actually be shifted into 2nd gear at a complete stop. That would be nice when I'm hauling 4 people around lol

 

No, not at a complete stop, but it doesn't downshift to 1st until the car is completely stationary. Before that it would downshift to 1st while I was still moving. If the car still has a bit of a momentum it stays in 2nd, so basically during what we call a California Stop it won't actually downshift to 1st. If I just stop for a fraction of a second it also won't downshift all the way, so I often continue in 2nd at a stop sign and I'm not rolling right through. I do stop to almost zero before continuing. Starting in 2nd from a complete stop is a different story. I don't actually like that. It's very laggy and awkward. Had a GLC 300 loaner recently and it would do that. Had to drive in S+ where it started off in 1st to not annoy me.

 

Ah, yes. Mine has to be completely still for it to shift to 1st, and this is what causes the jerk when I'm coming to a stop. I hate it haha. I prefer the car to downshift to 1st around 12mph because then it's not as jerky for me.

 

So, it jerks while you are completely stationary? Yeah that would be annoying. I guess that's a side effect of the torque converter. With the C63 the downshift to 1st happens with the startup clutch open, so it's completely imperceptible. Before that it was annoying, because it downshifted maybe around 5mph and re-engaged the clutch so it lurched due to the high engine braking effect.

 

Yup, odometer will actually display 0mph, and then the moment right before the car completely stops moving, it shifts into 1st gear and jerks. Makes my passengers think that I can't stop smoothly lol. To avoid this, when the transmission automatically downshifts into 2nd gear, I will immediately manually downshift it into 1st gear, and that makes it smoother. Either that or I push the shift lever into neutral and just stop smoothly that way, but that's more work cause then I have to shift back into drive.

 

Since Reduced engine mode has less umph than other 3 modes, I was wondering if it also translates into better mpg. It's not that I'm being cheap, but on my semi-annual 800-mile trips (which do not afford much opportunity for fun) better mpg determines whether I stop once or twice for petrol. Meanwhile, I have found using Sailing mode, which requires Comfort or Reduced AND auto stop/start, does seemingly hike mpg in relatively short highway trips. As always, YMMV.

 

At constant speed it makes no difference. The engine makes only enough power to maintain your speed. The glide mode is more likely to save you some fuel. Constant speed with cruise control also helps, however, glide mode is deactivated if cruise control is active.

 

I never noticed change in color before! DUH!! So many things to learn. Thank goodness for this forum. At 74, I've still got a lot to learn!

 

I notice that when I drive in Reduce mode, my MPG is a bit better in the city, mainly due to it limiting throttle input. However, if you can lightly step on the gas and not accelerate too much, then I would think that you'd also get the same result. I'm not sure if the engine being in Dynamic mode actually makes MPG suffer though. I do hear the engine (not the exhaust) more when ever I am in Dynamic mode and not just because it raises the RPM either, so I'm not quite sure what else Dynamic mode does.

 

I had the same issue with my 2019 facelift. Stopping in first, jerky downshifts coming to a stop, then moving off in 1st and rodeo jerking even with a steady foot. Or trying to take off quickly and it’d rodeo and cough and cut power in the middle of an intersection. What made worse was with the start/stop system restarting the car in 1st and if you didn’t have the brake pedal pressed very firmly, the car could lunge forward and hit pedestrians crossing in front of the car. The C43 is really not a well designed/programmed car. So many shortcomings, almost as though they didn’t properly finish development of the car. Normal Comfort drive mode on the facelift has such a retarded pedal it’s like Eco mode in most cars. Overall, unacceptable in my book.