MBStar

Can anyone explain the difference between the Manual
shift and the "optimal" gear selection on SL500 (not 55 and NOT Sport pckg)

Tapping to the left shlould result in a "manual style"
downshift (presumably by one gear).
Tap-and-hold to the left for one second, should result in the "optimal" gear being selected presumably
"optimal" for the throttle position). The implication
being that tapping to the left will not result in the
"optimal" gear but rather just one gear down
regardless of throttle position.

In fact, what really happens is that both tapping and tapping-and-holding results in the same result:
7Gtronic dowshifting to a gear dependent on throttle position (presuamably "optimal")

So again, WHAT IS the diffenrence?

jettie1767

On the SL55, you actually have Manual 'M' Mode which is different from just dowshifting/upshifting in 'D' mode. The Manual mode on the 55 is really manual meaning you have to do the shifting yourself. The only time it will downshift to 2 or 1 is if you come to a full stop. With the automatic down/upshifting, the car overrides your selection if it feels it's not the optimal gear to be in.

CASL55

I checked "do it all the time". By that I mean I use the paddles all the time. However, I never use the button on the transmission tunnel to select manual. I use the steering wheel paddles to force downshifts, but by staying in S mode, I let the car do the upshifts. The delay in M mode is not great, but is great enough that I can't always hit the red line and not bounce off the rev limiter; in S mode, the car runs right to the red line every time, if I've got my foot in it.

Being able to downshift to the lowest gear you're going to need in a given corner just before you turn in means no ugly downshifts in the middle of the corner to upset the car. After the apex and after I get the wheel unwound, I tap the right paddle to select the highest gear I'll want before the next corner, and let the car decide when to shift.

This is all in an SL55. The transmission in an SL500 may work differently.

Jim

CASL55

I was waiting for someone with all the inside technical data to answer this question, but that hasn't happened, so here goes, from my experience in several, but not all MB models.

On the AMG cars in C or S mode, hitting the left paddle or tapping the lever to the left lowers the maximum (numerical) gear selectable by one from the number displayed on the dash. Holding the left paddle or holding the shift lever to the left sets the maximum gear selectable to the gear that affords the highest engine speed short of the redline. That gear should provide the fastest acceleration (ie, the highest torque multiplication possible without overrevving the engine.)

On the non-AMG cars, tapping the lever to the left lowers the maximum (numerical) gear selectable by one from gear the car is actually in, which might be lower than the one displayed on the dash. Holding the lever to the left does the same thing as in the AMG cars.

Does that make sense to you? Does it square with your experience?

Jim

MBStar

Thanks CASL55, I see you also have an E500 which being an '05, also has a
7 G-tronic. On my SL500 (no AMG pck.) a tap causes a downshift by any
number of gears from one (with a steady speed, and steady accelerator position)
to 4 gears (with a decisive press on the accelerator). This throttle pedal
response is dependent not just on the depth but also the rate of pressure
on the pedal (rate of change detected similarly to how fast one takes the foot
OFF the accelerator - to activate the brake assist).
Tap and hold for 1 sec. , and you get essentially the same response under acceleration.
Under steady speed and throttle position, "tap" downshifts one gear,
while "tap-and-hold" for 1 sec, downshifts by several gears for unknown reason.
Thus revs increase and you now have "engine braking"

My point in all this:
They had it good with the way 5 speed trans. worked: tap = downshift by one gear
(regardless of the accelerator position) and "tap-and-hold-for one second"
and you have the optimal gear selection (now dependent on the where you plant the pedal.
You see I think they have let their engineers go out of control there at MB:
they took a good thing and messed it up: an example of "over engineering"
Just because you CAN do something doesn't mean you SHOULD do it.

If they produce the "manual mode" for guys like me who like to shift,
then why screw it up with too much technology.? I can see auto downshift on stop
and auto upshift at red line (I hate the feeling when the rev limiter actuates)
but this new set up is dangerous. Imagine coming out of a good corner and stepping on it
just after the apex, and just tapping once or twice on the shifter expecting
a one or two gear downshift respectively, and getting a sudden 3 or 4 geardown
with the rpms now going to the red line, the associated loss of traction and a whipeout.....
or at least lost time as you correct this by letting your foot off the accelerator or upshift frantically.
I get the feeling no one understands this on this forum: possibly because they don't shift
like most SL owners...
hey thanks for showing some interest...

lkirchner

The biggest change that I see in using the manual shift is that it brings out the roar in the exhaust and the dollar bills at the gas pump.

CASL55

Actually, since my 2005 E500 is a wagon, it has 4Matic and a five-speed transmission.

I believe that behavior is consistant with what I described. At a steady speed, the transmission is in 7th, and one tap takes it down to 6th. With your foot hard on the gas, it's in a lower gear, say 4th, even thought the display says "D", and one tap takes it down one gear to, say, 3rd.

Yes. You get the same response as under full throttle acceleration; the tranny is already in the lowest gear shy of the redline, and tapping the lever to the left will yield no change, as a further downshift would overrev the engine.


I think I explained the reason. Tap and hold is to get you ready so that, when you stomp on the acceletator, you will have the maximum possible acceleration without waiting for the tranny to downshift, because it has already done so.

My E500 5 speed has downshifts that (from your way of looking at it) are dependent on the accelerator position. My SL55 has downshifts that are not.

I can't argue with you there. I *much* prefer the way my SL55 operates

You are preaching to the choir. I totally agree with you. All the tranmissions should operate the way the AMG ones do. (And, from what you say, the way the five-speed regular transmissions used to.)

Jim

MBStar

Unfortunately, in 2005 even the 5 speed got the "new concept" that was introduced in the 7-speed transmission in 2004.


Thanks very much, I'll try to use it that way in preparation for the apex


As above, in 2005 they screwed up even the 5 speed transmission, save for the 5.5 Liter AMG cars.


Nice to know someone else feels same way...Thanks for your input and support..