why5-speed instead of 7

[is64fun]

well i thought a lot but could not come up with an apropriate idea why mercedes used automatic transmission in slr. moreover, why did they used 5-speed isntead of 7-speed which is newer technology? any idea

and the second question: the f1 transmission in ferraris, do they faster than the manuel gearboxes like carrera gt or the smg2 in bmw? and is selespeed different form those???

[TT]

Well for the SLR.. it was developped not really yesterday, and 7 gears gearboxes are still pretty new. The E60 M5 got one but its development started after the SLR's.. and of course also Merc is working on their 7 speed box, but I guess they were not ready for the SLR.

As for Ferrari's F1 tranny or BMW's SMG2, they maybe spoil a bit the fun of a good H gate, but for sure you can't be that fast with a manual box :D

I'd still take the wooden manual stick of the CGT anyday even if I will be slower than a 150 milliseconds F1 thing :D

[Buba81]

well i thought a lot but could not come up with an apropriate idea why mercedes used automatic transmission in slr. moreover, why did they used 5-speed isntead of 7-speed which is newer technology? any idea

and the second question: the f1 transmission in ferraris, do they faster than the manuel gearboxes like carrera gt or the smg2 in bmw? and is selespeed different form those???

As far as I know, and I'm sorry, because I can't deliver a link or proof of it, Mercedes will bring the 7 speed gearbox to the slr in the future...
But it has so much torque, the 5 gear speedshift does the job quite well... I mean, its not an ordinary 5 gear C-class automatic gearbox after all, this thing is really fast...

I actually don't know if the ferrari F1 Gearbox is faster tahn any of the others, but I think so... It's around 15 milliseconds in the most recent version... Again, no link for the proof, but a freind of mine owned a couple of Ferraris and also has a dealership (merc though;-) ), so I guess he' quite well informed...
But, anyone, fell free to correct me...

Have a nice and sunny sunday°!

Buba

[is64fun]

you are right. i also know that it is not a normal 5-speed c-class gearbox. but they are in f1. so they should know how to make it. their teammate mclaren developped a gearbox for the f1 car with 2 clutch. they might also take this in consederation. meanwhile as i know in f2003 or in f2002 the time for gearchange was 0.017 sec :) queit fast ha

[is64fun]

meanwhile thanks tt :)

[Ford Capri 2.8i]

I think simply that every big brand is making a lot of investment in this sort of gearboxes(and of course BMW, Merc and Ferrari are taking advantage of their formula 1 experience)....and i think that the future of the gearbox will be the gearbox with the 2 clutch similar to the VW group since it seems that its smooth, quick, the fuel consumption is not different from the manual gearbox.....we have just to wait for a little while in order to improve the 2 clutch gearbox making it as soft as the traditional automatic gearbox

[mindgam3]

The main difference between the F1 and the road versions of semi automatics are that F1 boxes dont need to be concerned about smoothness and not as much durability, at least not to the same extent, they just need to ram it in gear the quickest way possible.

Even on the early 360 models, there have been many complaints of their F1 clutches going after 5k, especially when left in automatic mode. The semi technology is improving all the time though and I guess in about 5 years or so semi auto boxes will be even faster, alot more reliable and a lot more smooth. I wouldnt be suprised if semi auto boxes were offered in just about all cars in 10-15 years

[Ford Capri 2.8i]

Apart from the good text of mindgam.......just to say that the semiautomatic gearbox(its efficiency when changing the gears is obvious comparing it with the manual equivalent) is spreaded from a long time ago in every race car cathegory such as the rallying, the hill climb championship F3000, the touring cars, and even in some of the cheapest championships.....such as the renault clio cup, or the rallying citroen C2 challenge in France

[Ford Capri 2.8i]

i forgot saying...apart from the text of mindgam, i agree 100% of his statements apart from the contribution that i made in the text before

[cooperluke]

wooden manual stick of the CGT anyday



It's the only slightest detail I don't like in the Carrera GT!! I think it has nothing to do with the car!! It should be in carbon fiber, or titanium, or kevlar!!
Wood? It seems like the one from a Jaguar, or a Rover...

That is why I don't buy one!! :) :) :)

[CSedl87]

The wood is from one of their race cars (I forget which one) that won Le mans. Back in the 60s/70s they didn't have use of CF or Kevlar, so the only way they could save weight was with balsa wood (which the shifter is made of), and Fiberglass. So it's an ode to it's predicessors.

[ZfrkS62]

mindgam3 pretty much hit the nail on the head.

BMW's SMGII has proven itself to be nicer on the clutch than the 6spd. And the SMGIII that is coming in the M5 should have even smoother shifts than what the M3 has when in programs S1-2 or in the automated modes. Even the next version that comes on the regular cars should have a smoother transition. As i've said in the other posts, (Leaked numbers on E55 vs M5) BMW will probably be replacing the automatic transmissions with the SMG in all their cars except the 7 series. Just as soon as they get the shift quality smooth enough.

As the article that is linked in the M5board.com meets Chris Bangle, said. Optimal shiting at 8300RPM manually will not be consistent. That is where the SMG takes up the slack.

As for the automatic over the manual in SLR. I asked one of the Mercedes techs I work with, why Mercedes didn't put a manual behind that engine, he said it's because they don't have one that is strong enough to handle the power of the engine. this doesn't surprise me since Mercedes hasn't had a manual transmission in the US since who knows when.

[sentra_dude]

mindgam3 pretty much hit the nail on the head.

BMW's SMGII has proven itself to be nicer on the clutch than the 6spd. And the SMGIII that is coming in the M5 should have even smoother shifts than what the M3 has when in programs S1-2 or in the automated modes. Even the next version that comes on the regular cars should have a smoother transition. As i've said in the other posts, (Leaked numbers on E55 vs M5) BMW will probably be replacing the automatic transmissions with the SMG in all their cars except the 7 series. Just as soon as they get the shift quality smooth enough.

As the article that is linked in the M5board.com meets Chris Bangle, said. Optimal shiting at 8300RPM manually will not be consistent. That is where the SMG takes up the slack.

As for the automatic over the manual in SLR. I asked one of the Mercedes techs I work with, why Mercedes didn't put a manual behind that engine, he said it's because they don't have one that is strong enough to handle the power of the engine. this doesn't surprise me since Mercedes hasn't had a manual transmission in the US since who knows when.

Don't forget about the little C-Class and the base model SLK...both are available with real three pedal manual transmissions. ;)

[ZfrkS62]

i think i remember him mentioning something about the C class but i haven't seen an SLK with a manual. If they're out there than ok, but as i think i've established thus far, i'm not a Mercedes fan :wink:

[Wutputt]

Well for the SLR.. it was developped not really yesterday, and 7 gears gearboxes are still pretty new. The E60 M5 got one but its development started after the SLR's.. and of course also Merc is working on their 7 speed box, but I guess they were not ready for the SLR.
Isn't the easiest explanation the fact that Mercedes' current 7G-Tronic auto transmission can only safely handle 700 Nm of torque and the SLR has 780 Nm of torque? And Mercedes had made a special reinforced 5-speed auto transmission (for their very ‘torqueful’ AMG-engines) that can handle 1000 Nm of torque.

So I think it was more a budget case:
Make a reinforced version of their brand new 7G-tronic transmission which would cost a lot of money to develop or use a transmission that can handle all the torque of the SLR and that is already available.

[jakaracman]

...
As for Ferrari's F1 tranny or BMW's SMG2, they maybe spoil a bit the fun of a good H gate, but for sure you can't be that fast with a manual box :D
...


Actually you can be faster than any of these, except maybe F430 improved F1 gearbox. SMG (and SMG2 too) is slow.

[Wutputt]

In the sportiest mode, when the the system makes use of the elasticity of the powertrain to induce specific speed oscillations, a SMG II for the M3 can shift in 80 ms. I don't think there are many drivers that can shift faster.

[jakaracman]

The fastest paddle shift currently is F430 with shift time of 150 ms (and that a good driver can do manually). SMG does it slower. For example, the old (2002) SMG needed approx 250 ms, the new one is a bit faster, but not much.

[Wutputt]

Well I also though the Ferrari F1 gearbox was the fastest. But I red in an ATZ article written by some engineers of BMW, BMW M, Sachs and Getrag the shifting time varies from 800 ms in the most comfortable mode to 80 ms in the most sportiest mode. In this mode the gearbox uses speed oscillations caused by the elasticity of the powertrain in such a controlled way to shorten the sychronisation phase.

[ZfrkS62]

Actually you can be faster than any of these, except maybe F430 improved F1 gearbox. SMG (and SMG2 too) is slow.


The SMG in the normal cars maybe. I don't know as i really havent driven any of those. But the SMGII has gotten faster. There have been a few bullitiens from BMW to reprogram the SMGII control unit so i think the times previously posted have gone out the window. I do recall hearing the the M3 shifted faster than the Ferrari gearbox but i'm not sure if that still holds true. You would be amazed what can be accomplished just by reprogramming. :twisted: :D

[T-Bird]

Since I've seen here that people were saying that Mercedes didn't start developing the 7 speed until after the SLR is somewhat wrong the transmission was being developed for about 2-3 years now and it is built by ZF industries not MB. (the same company who builds them for BMW, Audi and Corvette among others)

[Wutputt]

and it is built by ZF industries not MB.
I don't agree with this part. ZF is idd a major player in the transmission world for passenger cars. But the 7G-tronic MB uses, is developed by MB. Mercedes is still one of the few carmakers that develop transmissions in house. If I'm correct (but I'm not sure) ZF didn't even launched their 7-speed conventional automatic transmission.

[T-Bird]

From what I've heard from ZF engineers they helped develop the 7 speed with MB and BMW (key-word helped) but from how I interpreted it they produce it for MB.

[jakaracman]

Ive just driven M3 with SMGII and the new 911 with manual gearbox. You can shift the 911 faster than SMGII shifts (which is, as you say, faster than original SMG)...

[Wutputt]

Also if you put the transmission in S6 mode?


From what I've heard from ZF engineers they helped develop the 7 speed with MB and BMW (key-word helped) but from how I interpreted it they produce it for MB.
MB has it's own transmission plant, so it would be weird if they would let ZF to produce the transmission. For BMW's 7-speed SMG I don't really have an idea which partners BMW used to develop the transmission. But I'll try to find out in a couple of hours.

[ZfrkS62]

MB has it's own transmission plant, so it would be weird if they would let ZF to produce the transmission. For BMW's 7-speed SMG I don't really have an idea which partners BMW used to develop the transmission. But I'll try to find out in a couple of hours.


BMW's manual transmissions are made by Getrag.They're the only company i'm aware of that BMW has ever used for their manuals. BMW has been working closely with them to affix the electro-hydraulic unit on the shift tunnels to achieve the automated shifts. ZF is mainly an automatic supplier, much like GM's Hydramatic division.

[Wutputt]

Well did some research for BMW's new 7-speed automated manual transmission, the SMG III. But didn't find any reliable info regarding the partners they used to develop this new transmission. But since we now which partners they used one can guess which one they used. The SMG III probably was closely developed with Getrag.

I know previous SMG’s were built on existing ZF Friedrichshafen (5-speed) or Getrag (6-speed) manual transmissions. The clutch actuation and some of the hydraulics were developed by Sachs (owned by ZF nowadays) and the electronics were produced by Siemens (for the M3) or Magneti Marelli (for the 325 and 330i). BMW wasn't really satisfied with the result of the SMG I so, the development of the SMG II was done closely with Getrag, like you said ZfrkS62.

But sadly, like I said, I haven’t found reliable info regarding the SMG 7-speed gearbox of the E60 M5. But I guess the manual transmission is provided by Getrag, the clutch actuation by Sachs and electronics by Siemens, all under the authority of BMW. But I can’t be sure of it of course. Firstly cause there aren’t 7 speed manual transmissions for passenger cars on the market. So as opposed to the SMG I and II there isn’t a manual transmission were this new SMG III is based on. But since BMW had a good experience developing the SMG II with Getrag, one can guess the SMG III was also developed in co-operation with Getrag and the rest of the SMG II partners.



T-bird, I looked it up on DaimlerChrysler's website, and the Mercedes' 7G-tronic is produced in the Mercedes plant at Stuttgart-Untertürkheim. Did also some extra search regarding the partners they used for the development, but I only found the following. The 7G-tronic or codename W7A700, is an in-house Mercedes transmission. Basically it’s a further development of the Mercedes 5-speed automatic transmission by replacing one of the 3 planetary gear sets with a Ravigneaux gear set. The electronics are provided by Siemens but programmed by Mercedes. I didn’t found any reliable info that there were other co-operations during the development with other companies besides Siemens. But that doesn’t mean there weren’t. It’s maybe possible that Sachs (now owned by ZF) took part in the development of the hydraulics of the 7G-tronic. But since Mercedes is a competitor of ZF when it comes to producing automatic transmissions this isn’t really likely.

[is64fun]

and it is built by ZF industries not MB.
I don't agree with this part. ZF is idd a major player in the transmission world for passenger cars. But the 7G-tronic MB uses, is developed by MB. Mercedes is still one of the few carmakers that develop transmissions in house. If I'm correct (but I'm not sure) ZF didn't even launched their 7-speed conventional automatic transmission.

absolutly i agree with you. MB develops its own transmissions. they are creating the technology

[ZfrkS62]

But sadly, like I said, I haven’t found reliable info regarding the SMG 7-speed gearbox of the E60 M5. But I guess the manual transmission is provided by Getrag, the clutch actuation by Sachs and electronics by Siemens, all under the authority of BMW. But I can’t be sure of it of course. Firstly cause there aren’t 7 speed manual transmissions for passenger cars on the market. So as opposed to the SMG I and II there isn’t a manual transmission were this new SMG III is based on. But since BMW had a good experience developing the SMG II with Getrag, one can guess the SMG III was also developed in co-operation with Getrag and the rest of the SMG II partners.


if you look at the M5 pics that bmwmpower posted earlier, they show a cut-a-way view of the 7spd SMG and you can just barely make out the word GETRAG near the tailshaft of the transmission.
Before the M5 gets shipped to the states i'm sure some of us here at the shop (i hope i get to be one of the first :D ) are going to have to be sent out for training on it. so when that starts happening i'll let fill you in on some of the stats. Unless there's a German BMW tech that lurks in these forums that beats me to it...

i'm pretty sure Siemens is the one to have developed the SMGIII electronics, just probably built off the SMGII platform.

[Wutputt]

if you look at the M5 pics that bmwmpower posted earlier, they show a cut-a-way view of the 7spd SMG and you can just barely make out the word GETRAG near the tailshaft of the transmission.
Woow, some good viewing there! I didn't noticed that, thanks ;)


Before the M5 gets shipped to the states i'm sure some of us here at the shop (i hope i get to be one of the first :D ) are going to have to be sent out for training on it. so when that starts happening i'll let fill you in on some of the stats.
Can't wait until that happens. Should be a nice experience to have some training on it.

[Wutputt]

ZfrkS62, now I noticed it too. It idd clearly is Getrag transmission:

http://img48.exs.cx/img48/2742/P0016224.th.jpg (http://img48.exs.cx/my.php?loc=img48&image=P0016224.jpg)

[ZfrkS62]

if you look at the M5 pics that bmwmpower posted earlier, they show a cut-a-way view of the 7spd SMG and you can just barely make out the word GETRAG near the tailshaft of the transmission.
Woow, some good viewing there! I didn't noticed that, thanks ;)


Before the M5 gets shipped to the states i'm sure some of us here at the shop (i hope i get to be one of the first :D ) are going to have to be sent out for training on it. so when that starts happening i'll let fill you in on some of the stats.
Can't wait until that happens. Should be a nice experience to have some training on it.

especially since i think we get sent to the performance center in South Carolina for training...which means we may get to take them around the track there :lol: ::crosses fingers ::

[jakaracman]

Also if you put the transmission in S6 mode?

It's S5 now (the fastest shift mode)

[Wutputt]

I'm pretty sure here in Belgium the M3 SMG II has a S6 mode. If I remember correctly you'd have to switch of DSC to select it.

[jakaracman]

Yes, it is S6. I've counted the "dots" on the display wrong (went to the car and counted them again, and look, there are 6). But it's still slower than manual shifting.

[Pokiou]

As for Ferrari's F1 tranny or BMW's SMG2, they maybe spoil a bit the fun of a good H gate, but for sure you can't be that fast with a manual box :D



no way man... i reckon manuals are quicker.. but tthe advantage of autos is that in turbo cars and super charged cars u dont loose boost power when shifting gears.. but at the end of teh day .. a 5speed auto and a 5 speed manal .. the manual wins. !!! thats my opinion

[Wutputt]

An SMG, Ferrari F1, Selespeed, Sequentronic,... transmission isn't an automatic transmission. It's an automated manual transmission. It's the same as a manual transmission except for the fact that the selecting/shifting process and the clutch are automatically actuated. Like a normal manual gearbox an automated manual transmission will still interrupt the power supply when shifting, unlike an automatic transmission. So you'll still loose boost with one of those if the car is equipped with a turbocharged engine.

The only exception on this rule are the double clutch automated manual transmissions like the PSK, DSG or PSG. These can shift without interrupting the power supply, like a conventional automatic transmission.



Yes, it is S6. I've counted the "dots" on the display wrong (went to the car and counted them again, and look, there are 6). But it's still slower than manual shifting.
:lol:
You're the one who drove it. So if say they are slower, than it is.