Robert ...RAB

"AMG modified the shift programming of the M-B electronic 5-speed automatic transmission in the development of the SpeedShift transmission, which is perfectly suited for the sporty driving style available at the wheel of the SL55 AMG. It provides increased dynamic performance when required and refined automatic shifting under normal conditions.

SpeedShift's unique performance characteristics include:

35 percent faster gear changes than the conventional transmission.

Automatic downshifts, even double downshifts, under heavy braking.

Pre-selection of optimal gear for acceleration by holding the gearshift lever in (-) position.

Holding a gear when cornering.

Torque converter lockup in all forward gears.

Lighter torque converter.

SpeedShift makes the SL55 AMG driving all the more exhilarating through its unique Manual shift program and steering-wheel-mounted shift buttons."

...RAB

Drew

thanks Robert (once again ... setting the information curve!)

This trani will show up in the US right? As an option on the AMG or standard?

Where the heck will the 'steeringwheel shift-buttons go'? (its pretty busy on the wheel already!)

JamE55

Is this something like the SMGII on the E46 M3 or F1 paddle shift on the Ferrari?? Same concept shifting?

Doody

this is not a manual gearbox automated, like the SMG or Ferrari F1 stuff.

this is still an automatic transmission, and the steering wheel buttons are no different than the kind you find on many automatic trannies.

hopefully though, the tranny will be fast and zippy and smart. apparently the trannies on the new AMG cars (C32, SLK32) are much zippier than the older models. in fact, i'm curious to know if this is the same shifting system/programming that those two cars have, or whether it's been further refined (obviously the mechanical side has to be different or you'd end up with lots of busted metal!).

doody.

JamE55

So how would you differentiate this new MB speedshift tranny vs the ones on the M3(SMGII) and the ferarri(F1 paddle shift)?? Sorry but i'm not really clear on how this would be different if it's semi-auto??

Doody

check this article on Edmunds out:

http://www.edmunds.com/news/innovati...3/article.html

these trannies are the fastest way to shift gears (hence their initial appearances via F1 racing). the computers and hydraulics can engage the clutch, shift, and disengage the clutch faster than any human can.

apparently the removal of an auto tranny's torque converter is a huge speed win. i'm no mechanical engineer though, so "grain of salt" here.

i do know for a fact that AMG has yet to ship a consumer vehicle with any sort of manual transmission or auto-manual transmission. until the SL55 information, i have stayed away from AMG cars because of this. it looks like i'm going to suck it up for the SL55 though - woe is me

here are a couple links on how automatic transmissions work:
* http://www.howstuffworks.com/automatic-transmission.htm (also an article here on how manual transmissions work)
* http://www.edmunds.com/ownership/tec...6/article.html

doody.

JamE55

doody

This is the exact same concept as the new M3 SMGII. I mean the shifting is also controlled by the cpu??? I think MB calls it it's own speedshift kind of like on the M3 BMW calls it SMGII and ferrari calls their own F1 paddle shift.

sultan

It has to be different than the one's in the C32 and SLK 32, because MB said that it is the first model introduced with the speedshift tranny.

awiner

JAME55, the BMW SMGII is basically a manual transmission that is computer controlled to make it automatic of manual (What ever the driver wants to do). The Merecedes SpeedShift transmission is still a automatic in design with a computer controlled override. There is a big difference however in the way the units work. The SMGII is really a nice system, if, it works as BMW advertises and it doesnt explode like the original SMG transmissions.

Doody

JamE55 - do read the articles.

the CONCEPT of all transmissions is in fact 100% identical: provide different gearings so the torque of the engine can be utilized most effectively.

in PRACTICE there are MANY different ways to go about it. the different ways have plusses and minus regarding how fast they can change the gearing; how the gearing changes when the driver isn't controlling it directly; and what sort of work the driver has to do to achieve these changes. some of these differences are substantial.

if they weren't, we'd all be driving the one "Universal Transmission" that every automobile would utilize

doody.

JamE55

Awiner: You're correct in the fact that the SMGII is a munual tranny and that it is a computer controlled to make it an auto. I'm just trying to understand what makes this different from the MB speedshift technology in a nutshell.

doody: No argument here.

jco-amg

Check out the article in November's EVO magazine
"Old Cog's new Tricks" it is a review of all the various semi manual, clutchless, gear boxes with the latest auto boxes including that of the C32, the sequentronic in the C coupe...360 modena...SMG....etc

JamE55

Thanks jco!

vinmanc32

I thought this was the first car to use the SPEEDSHIFT technology. It is not the same as SMG on the M3. Dont be fooled. they are different. I dont know of one being better or worse than the other, but they are most definately different. I think the shift patterns are great on the C32. Supposedly AMG reprograms the cpu for the tranny for different shift points to emulate the feel of a standard, and the road holding capabilities. In turns, for example, it will hold the gear with out upshifting.

jco-amg

In the Evo article they felt that the Speedshift up shifted as fast as a clutchless manual or expertly shifted full manual.....that it held a gear well through corners...etc..their biggest criticism is that it down shifted sometimes when they didn't want it too....ie...giving it full throttle out of a corner where you wanted to use the car's torque for smooth, controlled acceleration...instead the car down shifted resulting in wheel spin which engaged the esp..killing speed...and upsetting the launch exiting the corner....I found with the CLK 55 that this could be controlled reasonably well by either disengaging esp...letting you control the oversteer more effectively or with esp on...with careful ie....less aggressive....throttle application...but did result in a less effective exit had one not had to worry about a down shift.