Jerry Schwartz

What does "W" do electronically & mechanically ..
(1) does W still use all 5 speeds/gears ?
(2) Is gas mileage mpg more or less in W ?
(3) Is W mode more horsepower or quicker acceleration ?
(4) If W provides quicker acceleration, is there any harm to leave car in W all the time ?
(5) How does W improve driving in wet/icy conditions ?

MarkL

I don't have my owner's manual in front of me, but on the C240/320, I believe "W" mode starts in 2nd gear for less chance of wheel slip. Also, I think there's a different reverse gear ratio.

BTW, I've got a 6-spd so I can't attest to its operation -- but I did READ about it in my manual

young

that's right, 'w' starts in 2nd gear. for 'winter' mode. not too useful yet and i need it for the hills that i live in.

DrMike

The "w" mode does automatically what I was taught to do when starting the car on a slick surface: drive like you have a raw egg between your foot and the gas pedal--press very gently.

Jerry Schwartz

Maybe the MB Tech has the rest of the answers ...

Jerry Schwartz

So what gear does the auto start in when in "S"

MarkL

1st gear! "S" is the "standard" mode.

MB-BOB

From page 253 of Sedan owner's manual on "Winter" mode...

- The vehicle starts out in 2nd gear...
- The "W" mode helps improve traction and driving stability of the vehicle.
- The gear shifting process occurs at lower vehicle speed and lower engine speeds than in the "S" program mode.

I'm not mbtech, but my ideas are (some repeating from previous posts):
1) W uses 2-3-4-5 only, start from stop in 2 rather than 1.
2) I would think mileage during icy/wet/snowy conditions would be slightly worse, regardless of starting gear chosen (due to conditions rather than gear selection). In dry conditions, the "short-shifting" at lower rpms might seem to provide better mpg, at a slower acceleration penalty. I wouldn't pay that penalty, myself.
3) Given that the shifting process occurs as lower RPMs in all gears (less aggressive), I should think acceleration would be slower to any given speed.
4) IMO, I would not leave in W all the time (due to item 3 consideratoins). I've heard suggestions that W is good in stop and go traffic (keeps from constantly downshifting into 1st) But I haven't tried this... not sure I want to. Besides, manual cautions not to engage "W" unless from the "park" lever position... not switchabe on the fly... inconvenient, if you have mixed city/hwy driving conditions.
5) W is only intended to assist in getting you moving from a stop in snowy/icy conditions by limiting wheel spin normally associated with 1st gear (less wheel spin in 2nd). Advancing the gear changing map for other gears is also intended to limit wheel spin in "iffy" conditions. Hence, using "W" in other than snowy conditions would be a waste, IMO.

This topic is covered in your owner's manual. I have a C320 sedan, so don't know the exact pages in your Coupe manual.

If you want mbtech208's attention to this, suggest you move or repost this to the MB Tech Talk forum, posed as a general question for all MB's with auto trannies (I guess most if not all have W/S modes).

mbtech208

What do you need me for? You guys have hit all the main points of winter mode!

pokerFACE

Shifter has to be in Park or *Neutral* to toggle between W/S.

W also lets you start in a second Reverse gear. BTW, this is extremely slow gear (umm.. low/high. dunno) and it's a pain. I'll use the second forward gear, but you won't go anywhere too quickly with R#2.

It snowed here in Toronto last Friday. My C240 auto on allseason Continentals did fine. My only problem was switching lane on the Gardiner Expressway when the ESP light went off.. scared me for a bit when all I did was a slow graceful lane change and I didn't feel any instability. Must have been black ice?

MY friend on the other hand, ugh.. 325xi on Pirelli 210 snowsports.. er.. plowed right into a curb. $2400 in repairs. 2 bent rims, and suspension damage. They want to charge him $500canadian per 16" wheel!!!

Jerry Schwartz

Did your ESP light go on (illuminated) or go off ?

jswedberg

That's not true. The manual suggests this as safest, so you aren't surprised by the gear changes, but you can toggle between W and S while in motion.

Also, W mode will still use first gear if you stomp on the gas hard enough from a stop.

MB-BOB

Actually, I'm not sure how W mode works in conjunction with ESP. I'm probably missing something, but to me, ESP is like driving in W mode... if you're too aggressive on the snow, isn't ESP going to do its stuff to restore traction, thereby taking the place of W mode? (Plus you retain 1st gear and normal upshift points on less slippery pavement).

So, aren't ESP and W mode redundant? If not, which system has priority? Which system works first?

MarkL

I would perhaps compare "W" mode w/ the traction control component and not ESP. I believe ESP is a separate function from "plain-vanilla" traction control. Elsewhere on this board, people have mentioned that turning off ESP via the dashboard switch does not disable traction control. Traction control simply controls wheel spin, whereas ESP monitors vehicle direction vs. inputs (i.e., steering angle vs. yaw rate) to apply the brake at one or more "corners" to bring the car back into its intended path.

I guess you could say that by using "W" mode, you will avoid having the traction control engage since you may be less likely to have a wheel spin on takeoff to begin with.

pokerFACE

Yes it did. I was just changing lanes (maybe a 10 degree turn on the steering wheel), and the ESP flashed. I know that snow repeatedly compacted by tires on teh hwy turns into ice, so it was probably that.

Well so far, given that I'm one of the worst out there I'd liek to testify that ESP and W mode work.

Oh, I just remembered. That night it snowed I pulled into my driveway and waiting for the garage door to open so I can park the car. I got stuck on the driveway! It was still in W mode and the ESP light kept flashing.. that was annoying as hell. WTF? Okay, the driveway leading to the garage was on a slight upgrade, but I get all the way home to get stuck at the door of my garage?

Jerry Schwartz

I do not have experience with ESP. Is ESP engaged all the time ? When the ESP triangle symbol is on the computer display , does that mean that ESP has engaged or does that mean ESP has been disabled ? When pokerface says while in his driveway, ESP was flashing, does that mean ESP was engaged ( On) ?

pokerFACE

ESP is by default on all the time. It's (supposed to be) always at work cleaning up any possible traction or stability problems, and from experience, it only flashes in the dashboard when you just did a major screwup (which doesn't explain my lane change incident). Generally, the ESP light flashes if it has to intervene in a major sense. If you turn the ESP off, it's still partially active (only traction control), and the ESP light will remain lit constantly, and flash if wheelspin is detected.

ESP was flashing on my driveway because there was ice when I tried to pull into the garage. Some wheelslip, so intervention by braking and torque reduction.

pokerFACE

btw, ESP is the directional stability program. It also amalgamates ASR, which is a traction control using braking of drive wheels plus torque reduction. ASR is an advancement of what they had before.. ETS, which merely brakes drive wheels during wheelslip in acceleration (up to a certain speed only. ASR supposed to take effect in any speed).

What I don't know is if you shut off ESP, which leaves you with traction control only, is if you are left with ASR or ETS (the difference being the availability of torque reduction)

Oh well.. I'm not stupid enough to turn it off in adverse weather conditions