M/m Vs Manual Gear Ratios

[Sorin]

A friend of mine has a Citroen C1 with manual transmission and it seems to me that his car accelerates faster regardless of what gear he's in. Does anyone know if the gear ratios differ from the automatic ( M/M) to the manual transmission? Thanks!

[Jan van de Wouw]

They're the exact same gearbox. Only difference is the ay the gears are selected;

on a manual there are cables that attach the gear stick to the box, on an MMT these cables

are replace with actuators that move the exact same levers on the gearbox and clutch.

[Sorin]

Thanks! I'm glad to hear this. I did't exactly know what "robotized gearbox" ment. I was worried that it would be a classic automatic gearbox and it would be affected by my driving style, which isn't very "orthodox", especially on the mountain roads that are close to where i live.

[miss_d_bus]

Thanks! I'm glad to hear this. I did't exactly know what "robotized gearbox" ment. I was worried that it would be a classic automatic gearbox and it would be affected by my driving style, which isn't very "orthodox", especially on the mountain roads that are close to where i live.

Realistically though, my car seems very sluggish at times and I have the MMT. I have put it down to the small engine as well.

The problem might be more to do with the gear the car selects for you. I have been told by a manual driver that my car is in gears they won't have been in if they were driving their own car. If it bothers you, you could try the semi-automatic element of the gearbox and change the gears yourself but of course without the clutch!

Quite often I am going down a steep hill (14%) near by home and the car sticks it in 4th when there's signs everywhere saying drive in a low gear so its not necessarily going to work out that you are going up or down hill and change accordingly but rather I think it works the gear out based on speed? (I'm guessing here a bit)

[Zaaro]

not too sure what it bases it on when going downhill, must be speed though. I find 3rd is sluggish for me, every other gear is good, after first starting in the morning usually it is quite sluggish so i usually put it into manual mode and have a switch thro the gears for 5 mins, seems to help.

[Sorin]

I noticed that it changes gear depending on speed and how much the accelerator pedal is pushed.

[Jan van de Wouw]

The accelerator pedal on an MMT is "drive by wire".

So where on a manual box you actually control the throttle with your foot,

on the MMT the accelerator isn't linked to the throttle directly.

You have to look at the pedal as a "speed-pedal": you press it to go faster

and releas to slow down. The car then works out what throttle-position and

gear are most suitable, depending on spead and load of the engine.

It might also be usefull to know that the box has been setup to be economical,

that is why it changes to a higher gear as soon as possible; to conserve fuel.

I'd suspect that's why it changes UP when you go down a hill:

higher gears would make the engine turn less, thus being more economical...

[Zaaro]

thanks for that Jan, nice explanation of how the MMT works :)

[rplyons]

Hi there,

I agree with what's stated above - I'm a coach driver and the vehicles that I regularly drive are either Fully Automatic transmissions, or (like the M/M Transmission) 'Automated' Manual Transmissions (or AMT for short).

The vehicles we have our all Volvo and from 55-Reg onwards we have the Volvo I-Shift transmission, which is exactly similar in technological terms to Toyota's M/M Transmission in the AYGO...with additional features like an E/P button to switch the gearbox from Economy mode to Performance mode and vise-versa...and the Gas pedal has a physicial kick-down switch so that you truly know when you're going full throttle but remaining in the Economy shifting pattern, unlike the M/M Transmission AYGO I test drove where there was no physicial barrier at all, so you either had to go 99% full throttle and not hit the carpet to prevent the kick-down from activating, or drive it in the "M" position and go through the gears when necessary to drive eco-friendly. Personally if I ever decided to get a M/M AYGO I'd have the kick-down programme turned off as that would constantly annoy me!

However, Toyota's M/M Transmission does have a specific piece of technology built into it that I adored and which no other (to my current knowledge) AMT currently provides inc. the Volvo I-Shift...assist pull-away - where when you release the footbrake or disengage the parking brake the M/M system will half-engage the clutch. Although for things like uphill gradient starts (or downhill gradient starts in Reverse gear) you "must" depress the Gas pedal before releasing the footbrake/parking brake as the assist pull-away programme doesn't engage the clutch that quickly nor a sufficient amount to stop you losing crucial pulling away control.

However, the M/M transmission only costs an additional £500, which I think is a fantastic price and you Do get Value-for-Money in terms of what it can do and how well it actually does it - I've driven loads and loads of different vehicles with AMT and Fully Automatic gearboxes and the M/M makes driving the AYGO much easier!

Richard

:)

[rajivrattna]

My wife has an Aygo (2008) with MMT box and she has been given a special driving tip by the dealer which works very well. As you are driving along on automatic (E-mode) and think that the Aygo should have changed to a higher gear but it has not for some reason, then just release your pressure on the accelerator very slightly and it will change gear to a higher level. We have tried this on our long trips on the high way and in the city stretches and it works very well. You some how coax the gear to shift the gear earlier than it would have done other wise. I use this all the time when changing from 2nd to 3rd to 4th and 5th gear in the E mode. I have never seen this happen in other "normal automatic" cars before.

[Cyker]

So it works kinda like the kickdown but the other way!

[grinner82]

I think the manual has very long gears, the car seems to go for ever in second and third, dont know what the top RPM is for each gear, but I have had 50+ in second gear and its quite responsive on acceleration at the top end.

[Unklian]

Just to add my 2p worth about the "cleverness".

The ECU has a short memory feature of how the car is being driven.

If you use large throttle openings a few times, it will hold onto lower gears for a few changes.

Another thing......difficult to describe......

Near my house is a long constant downhill stretch. At about 40mph, my MMT is normally in 4th / 5th.

If I stamp on the brake harshly at the same speed, the MMT will change down to 3rd and hold that gear

for about 50 yards until the software decides the "emergency" is over.

Give it a try yourself!

Also, descending long hills, a conventional auto box will just change up until you are in top gear..

You then lose a lot of engine breaking.

I f you are descending a long hill with MMTat say 30mph, with your foot off the throttle,

If the road becomes more steep and the car accelerates due to gravity, after a while, the MMT

will change DOWN to give more engine breaking......very clever.

Ian.

[zakelwe]

I think the manual has very long gears, the car seems to go for ever in second and third, dont know what the top RPM is for each gear, but I have had 50+ in second gear and its quite responsive on acceleration at the top end.

The Aygo gearing is ridiculous. It's all to help fuel economy of course but it really blunts acceleration. 2nd will take you to above 60, 3rd to 90. For a car who's top speed is less than 100 that is silly. 5th is geared for 145mph

Andy