seahonu

Curious on which setting you use, C-Comfort or S-Sport mode for the auto-transmission? I've had my CDI for just over a year and alternate between C and S modes. I drive pretty spirited and demand to have access to as much torque/HP as possible. I find that the S-mode does take it up to higher RPMs but that doesn't seem to get more "power", ie. sensing from my "butt-dyno". And that in C-mode, the power seems to come on stronger at lower RPMs, but shifts to soon. Thoughts?

Diesel Benz

Well I do use mostly "C", sometimes "S" and very infrequently "M".

If you kick down, it should not matter if you are on S or C except that the car needs to change first from the second to the first gear (if the speed is low enough for the first gear).

I did not find the W211 power curve but from the attached W221 figure you can see how the car should change gears. Taking a typical gear ratio of 1.4 between consecutive gears, the car should rev up to some 4200 rpm where it would go down to 3000 rpm with the next gear. You can see at 3000 you would get the same power as at 4200, the average power being maximised with that gear throughout the used rpm range.

philfna

I drive in C most of the time.

lkchris

Have run in S from day one, even for break in.

No reason for 2nd gear starts and rpm limiter except perhaps if it ever snows.

philfna

Yeah I would agree except it snows a lot here.

pinebaron

C for driving in my development and parking in my garage; S for everything else.

berrill

Could someone please explain the difference between C and S I notice no difference.

Diesel Benz

Which car do you have? I mean I guess it is a W211 but which model and which tranny specifically?

On the 7G-tronic the car starts with second gear on C and changes up at lower revs on C.

I may remember wrong but at least my W211 5-speed starts with first gear, not sure if all models do. In any case it would change up at lower revs on C. This may not be easy to notice though.

LaicepsYdobon

C stands for Comfort mode. From a stand still the car starts from 2nd gear forward and reverse. The transmission is mapped to shift before 3,000 rpm when driven in a normal normal fashion. The car is also more inclined to shift up to a higher gear to produce a more comfortable ride.

S stands for Sport mode. From a stand still the car starts from 1st gear forward and reverse. The transmission is mapped to shift after 3,000 rpm and is more on the reluctant side to shift up maintaining higher rpms to produce more torque.

According to the manual during the break in period the car should be in C mode until it settles in and the revs should not exceed 2/3 of the engine rev band.

I drive my car in C mode because I sit in bumper to bumper traffic every morning and the acceleration is much smoother in C mode because it starts from 2nd gear. On a side note I also noticed that breaking is also affected by which mode the car is in. In S mode I have more dead play on the break and then suddenly the breaks bite. In C mode there is no dead play on the break and the break bite feels more uniform.

philfna

Yeah the braking issue is annoying in S. I am in C a lot for the same reason...wish I had somewhere to let this all out.

berrill

I have the 320 cdi. I must say I notice almost no acceleration differences what so ever, in fact sometimes I find C mode has better acceleration. Maybe this is due to the huge torque the engine has at lover revs. I suspect this diesel pulls better at low revs. I have the 7 speed tranny. Thanks for the info going so see if I notice any difference today.

Cheers

Baron11

I have asked the question about starting off in 2nd gear when using the comfort mode or C, and my vehicle always starts off in first gear no matter which mode I am in. Is this normal?

Bryan

LaicepsYdobon

7 speed tranny with the torque of a CDI engine you will have silky smooth never ending power flowing from the engine. I have a 5 speed petrol engine that is why the S and C buttons make a noticable difference for me. Plus you are getting way better gas milage then me

LaicepsYdobon

How can you tell you start off in first gear even in C mode ? The only way I ever managed to get my car in first gear in Comfort mode was to start rolling (in 2nd gear) from a complete stop and then floor the accelerator forcing the transmission to kick-down to first gear. If your car does indeed start off from first gear in C mode its not normal. You might want to talk to your SA about it. It could be something as simple as the button which selects which mode you are in is not working.

Diesel Benz

The engine would pull fine at low revs but you would still get better acceleration when starting with first gear (except if you try it on a wet road, the rear wheels tend to spin even on a dry road).

If you use kick down, the car would anyway change to first gear and the only difference between C and S is that there is some delay from the shift.

It is pretty difficult to figure out which gear is on while accelerating at full power. It all happens so fast anyway.

seahonu

Thanks folks for all your observations on this C or S mode. I hadn't realized braking was altered too! I wish we could customize the behavior of C or S mode. I'm not quite happy with either mode. C is too delayed from a start and S hangs up in the high RPMs too long. Actually I find that C responds quicker for lane-changes, being able to push the throttle without a shift. S seems to be delayed abit with the shift-down on a lane-change. I'm wondering whether these modes were for the gas version and not the CDI.

frogstaple

I use S all the time. The kick-down into 1st when accelerating from a stop in C can't be good be good for the transmission.

Untertürkheim

C most of the time, there is enough torque to move without having to rev higher. Sometimes I put it in S just to have some fun, but I prefer the smoother shifts of C in most cases.

harkgar

C mode in winter and S mode in summer.

Toronto is so cold and icy it makes sense to use C now. In San Francisco it makes little difference apart from fuel economy.

LaicepsYdobon

If you are experiencing a kick-down from 2nd to 1st from a stand still in C mode means you have a lead foot. You should definitely stick to S mode

frogstaple

I know!

Polar Bear

This should answer the question about his lead foot and why he prefers "S."
http://www.youtube.com/watch?v=oTsN2eK0MQs

Baron11

I spoke with SA and he too said C mode should start off in second gear. I count the gear shifts and based on what I come up with is 6 shifts regardless of which mode. I have even tried rolling from a stop, then flooring the pedal, no downshift. Based on what I have seen/felt so far, it starts off in 1st.

Do we know for a fact that the 7speed tranny combined with the bluetec is supposed to start off in second? I know the 5speed cgi is supposed to, but I can't find definitive info on the 7 speed, bluetec combo. Any help is appreciated.

Regard,

Bryan

Diesel Benz

The info I was able to find states that the 7G-tronic would start on second gear when at C, on all models. It does appear to be like that for the 5 speed tranny 722.6 too, at least those I looked at (previously I thought some 5 speed trannies would start with first gear, could have been justified from the lower number of gears and longer first gear).

LaicepsYdobon

Yes all Benz's start off in 2nd gear if C mode is selected. The BlueTec has so much torque that you could even start in third and you would not feel any difference