The Answer to SMG vs. 6-speed - The Unofficial BMW M5 Messageboard (m5board.com)

Yupkwondo · 13th February 2003, 06:43

After all this SMG, 6-Speed debate...what would be the possibility of a transmission that could do both. I know it's not in development,(well as far as I know) but if you thought about it, I don't see how hard it could really be. (Take that in terms of what they have accomplished already, it's way to hard for someone like me to develop)...Anyway, as I see it, one would need a dual cylinder clutch, one for the pedal, and one for the SMG. The computer could control which one works when, through a pressure release valve, that switches to whatever one needs the pressure at that time. And you would need a way to change from a stick control, to servo activated gear changes. Again, I'm sure there is a way to do this. A "7th gear" where you put it and the servos/pneumatic valves that do the actual gear changes start to work. I think that would be the ultimate way to progress, the two in one possibility of full manual control, and true race inspired SMG!!

Or, as another way to develop the system, you could have a manual/stick that is drive by wire. As you move the stick the computer uses sensors, to control the transmission through already controlled means that a SMG has. SMG already has different speed controls, and the car has enough computing power to know/learn how to work the clutch with a variable input, not just given parameters. Using this method there wouldn't have to be a way to switch from true manual to SMG manual, it would all be SMG components with even more User interface.

Or it could then have a "button clutch," full clutch movement, and feel however the computer would again sense position and react in the way it needs to. So if the processor does 1000 positions per second, there would be no way to know what was controlling your clutch activation. Then when you goto true SMG mode (again the "7th Gear") you goto the fully auto paddles on the wheel,and the 5ms shifts, or what have you.

If I had the development money, I would truly pursue this idea, as I feel that it would be an enthusiast dream, well as long as they aren't a purist and an enthusiast!!

~ Jason
2001 Lemans/Lemans

Tom C · 13th February 2003, 23:47

Jason:

How about a hybrid of your drive-by-wire idea:

The clutch pedal itself is clutch-by-wire technology. The clutch is actuated by the clutch pedal but not by cable...but by electronic sensors connected to the clutch pedal. The car could have a standard/default setting of the manual transmission. Then you could have a switch where you could go to a fully electronic automatic. Once the auto is engaged, the electronics could control the clutch itself by sensor readings on the throttle. You would probably have to electronic control the stick shift itself too....where you are banging it around but not actually "shifting" into each gear in the manual setting.

Just a thought (maybe a deeply disturbed one at that)

Tom

Enigma · 14th February 2003, 03:02

Why add all this complication to a system that already performs better than the human can just to give them more work to do?

alpinadvl · 14th February 2003, 06:40

RUF has already developed a clutchless 6-speed...... this may be of interest to you.

MEnthusiast · 14th February 2003, 14:28

Quote:

Originally posted by Enigma
Why add all this complication to a system that already performs better than the human can just to give them more work to do?

well, I think there is the "fun factor". for example, to take your statement to the extreme, why even have cars that we drive? Computers now could drive the cars much better. we have radar cruise control, systems that self park cars, etc.... or why not have cars that are manufacturer limited to the speed limit? Im sure it would save lives and fuel.....

I think the ideas for a dual traditional/smg system are very interesting. Id be in favor of it if it didnt affect performance.

Z8Bob · 14th February 2003, 19:31

I think the idea is very creative. The Throttle is already a wire system, and MB uses it for braking on the SL (some early mixed results) so why not the shifter and the clutch...

I sent the string on the BMWNA managers

MAVERICK · 15th February 2003, 16:28

Jason, what made you think of this innovative idea?

Shifting (no pun intended) from a 6-speed manual to an SMG at the touch of a button and testing this system all day long would be a nice task.

Skeptic question: Mercedes has done a lousy job with their fly-by-wire braking in terms of feel and modulation ( not to mention stopping distance -- C&D W211 E55 roadtest). So if BMW were to go electronic with the clutch, how would a driver sense the biting/engagement of the clutch through her foot? Could we get used to having no engagement feel in the clutch?

Another question: With present manual gearboxes we, purists, have complete mechanical control over the car's clutch and gearbox. Suppose the electronic accelerator goes berserk, we can always take the car out of gear and coast in neutral. If we allow the accelerator, brake, clutch, gear lever, and steering (Active Steering) all be controlled by "I-drive-you-don't" computer, will we be truly happy or simply muttering under our breath about the good ol' days?

Any experienced pilots out there who can compare and contrast the feel of flying fly-by-cable versus fly-by-wire commercial/military aircrafts?

MEnthusiast · 15th February 2003, 16:58

I think those are great questions. Ive heard that the MB brake by wire system is getting mixed reviews and also is somewhat problematic. Im sure they will get it right in the next year or two.

My opinion is that BMW generally does things the right way and if they could do a system that Jason suggested and we think is a good idea, I have faith that they would impliment it in a way where it has the proper feel. maybe it would take them 5 years to get it right, but I think they would in the end.

as to safety- lets face it, what happens if the steering system fails us right now? I know someone who had something like this occur while he was on the highway!!! Hes uninjured, but that was very scarey.

ajsd · 15th February 2003, 20:23

What Jason suggest should be fairly straightforward for a manufacturer to develop. When semi-automatic gearboxes were first introduced in Formula 1 by Ferrari and then by Williams the drivers still had a normal foot operated hydraulic clutch for starting and the eletronics only took over clutch control on the move. Adapting the system for road use and getting automated clutch control to work properly from a rest is the biggest challenge for getting a SMG type system to work in a road car. Having a system where the driver could elect to disable automatic clutch control and use a foot pedal but shift the gears through either paddles or sequential stick should be fairly simple to engineer. It would be great for city driving (a would save lots of warranty costs for manufacturers for burnt out clutches). I have the misfortune of having to slog through London tarffic on the way to work every day and it is painful to be in traffic near a Ferrari 355 or 360 F1 or an Aston Vanquish and listen to the clutch slip that's programmed into the system to allow them to deal with slow moving traffic.

Enigma · 16th February 2003, 01:08

I am sorry to say it but this is a dumb idea. The pureist drivers that want the clutch pedal and gearshift the way it is right now will find somethign to had about anything with added electronics just as they always do.

The SMG camp will see having a pedal that they never use as stupid. Also making an smg like shifter is a bad idea. Push forward for down and back for up is much simpler than an H pattern while on the track...

MEnthusiast · 16th February 2003, 03:49

do you mean like power steering, power brakes, abs brakes, dual or multiple mode steering and gas pedal sensitivity, traction control and synchromesch gear shifts?

I disagree with you that the idea is dumb- I think there is real merit to it; but I agree that there would be some obstacles to overcome, but isnt that always the nature of progress?