Difference in Automatic Transmissions

[Drlonline]

Does anyone know the differences between the automatic transmissions available with the v6 vs. the i4 AMG other than the # of gears (6 vs. 8) and presumably the gear ratios?

 

[Bod27]

Does anyone know the differences between the automatic transmissions available with the v6 vs. the i4 AMG other than the # of gears (6 vs. 8) and presumably the gear ratios?

The AMG is a DCT type and the Toyota one is a torque converter type .

 

[Tokion]

Does anyone know the differences between the automatic transmissions available with the v6 vs. the i4 AMG other than the # of gears (6 vs. 8) and presumably the gear ratios?

What is normally called “automatic transmission” is a normal torque converter transmission like the Emira V6 automatic has got (supplied by Toyota). This is used in the majority of all cars that are said to have an automatic transmission. Probably (arguably) the best such transmission today is the one from the German firm ZF, and it is used in most BMW models (recently with 8 gears), but also in many other brands.

PDK, DCT and DSG are different names for a technology where two clutches shift between different fixed gear ratios along a twin-axis system. PDK stands for Porsche Doppelkupplung, DCT stands for Dual-clutch transmission and DSG stands for Direct-Shift gearbox. The Emira I4 has got such a transmission (supplied by Mercedes AMG). This type of transmission provides the quickest gear shifts short of pure racing sequential transmissions. Interestingly Bugatti Veyron and Chiron models have such transmissions. Another noteworthy model with DCT is the Nissan GTR. And many Ferrari models and other high end super cars also rely on it.

The third major automatic gear system is CVT which stands for continuously variable transmission which is an automatic transmission that can change through a continuous range of gear ratios. This contrasts with other transmissions that provide a limited number of gear ratios in fixed steps. One manufacturer of sporty cars that offer highly developed CVT transmissions is Subaru. Even if the transmission itself is continuously variable; manufacturers often build in “steps” that let the driver shift “gear ratios”, sometimes as much as 10 levels in a recent version of Toyota GR Yaris currently only sold in Japan.

 

[Fido]

Yup, that’s pretty much it. The conventional auto uses a fluid flywheel/torque multiplier and a series of epicyclic gear trains to “slide” between ratios. A DCT is more an automated version of a conventional manual gearbox. It has input and output shafts and a number of fixed ratio gear pairs that it switches between. A dual clutch arrangement takes the form of two boxes back to back with the next ratio pre-selected. When it changes gear it disengages the one clutch and engages the other. This can be done very quickly as the actual gear change is then done on the undriven clutch side.
CVTs are a bit of an abomination in my opinion but then I remember the old DAF variomatic. They use a ‘vee’ shaped belt connecting two variable diameter pulleys. The sides of the pulleys move in and out to force the vee-belt to a different radius and hence the ratio can be infinitely varied between two fixed limits. This is wonderful in theory as it allows the ratio to vary and ensure tractive effort and engine speed are continuously optimised. In practice the engine sits at max torque speed until the box reaches the max ratio and then the revs climb. The sounds produced are not attractive, the engine sits at constant revs whilst the gearbox hoo hoos its way to top speed and then they swap over and the engine revs rise and the gearbox noise stays constant.

 

[Drlonline]

Thanks for the explanations. I suspect the quicker and more efficient shifts in the DCT also helps explain the AMG’s slightly faster 0-60 time.

 

[Tokion]

Yup, that’s pretty much it. The conventional auto uses a fluid flywheel/torque multiplier and a series of epicyclic gear trains to “slide” between ratios. A DCT is more an automated version of a conventional manual gearbox. It has input and output shafts and a number of fixed ratio gear pairs that it switches between. A dual clutch arrangement takes the form of two boxes back to back with the next ratio pre-selected. When it changes gear it disengages the one clutch and engages the other. This can be done very quickly as the actual gear change is then done on the undriven clutch side.
CVTs are a bit of an abomination in my opinion but then I remember the old DAF variomatic. They use a ‘vee’ shaped belt connecting two variable diameter pulleys. The sides of the pulleys move in and out to force the vee-belt to a different radius and hence the ratio can be infinitely varied between two fixed limits. This is wonderful in theory as it allows the ratio to vary and ensure tractive effort and engine speed are continuously optimised. In practice the engine sits at max torque speed until the box reaches the max ratio and then the revs climb. The sounds produced are not attractive, the engine sits at constant revs whilst the gearbox hoo hoos its way to top speed and then they swap over and the engine revs rise and the gearbox noise stays constant.

Thanks for filling In more technical and supplemental information to my own post. That's the right spirit❣️

I am not going to argue in favor of CVT, but I have a 300cc Vespa GTS scooter that’s got it, and it really fits well and works excellently (extremely quick). And today I have rented a Toyota Yaris GR with a so-called “10-speed” CVT (of course there is no need to use these “steps” unless you want to “play”). This Yaris GR is a non-turbo version with only 120hp, but it is very light, so that may be all it needs. Same 3-cylinder engine. (In the US you’ll only get the GR Corolla, but presumable with a 300hp plus 3-cylinder turbo, and only with manual transmission.

I have an EMIRA I4 with DCT on order (going on two years now), and I am particularly looking forward to driving with the DCT transmission. I have lots of experience with both manual transmissions (e.g. I owned three Mazda RX-7 rotary sports cars in a row) and torque converter automatic (ZF 8 speed etc) cars (BMW E93, F31).

 

[MickOpalak]

Also worth noting to a Lotus fan is that DCTs are the heaviest transmissions out there, quite a bit more than a torque converter auto or a manual.

 

[Drlonline]

Thanks for filling In more technical and supplemental information to my own post. That's the right spirit❣️

I am not going to argue in favor of CVT, but I have a 300cc Vespa GTS scooter that’s got it, and it really fits well and works excellently (extremely quick). And today I have rented a Toyota Yaris GR with a so-called “10-speed” CVT (of course there is no need to use these “steps” unless you want to “play”). This Yaris GR is a non-turbo version with only 120hp, but it is very light, so that may be all it needs. Same 3-cylinder engine. (In the US you’ll only get the GR Corolla, but presumable with a 300hp plus 3-cylinder turbo, and only with manual transmission.

I have an EMIRA I4 with DCT on order (going on two years now), and I am particularly looking forward to driving with the DCT transmission. I have lots of experience with both manual transmissions (e.g. I owned three Mazda RX-7 rotary sports cars in a row) and torque converter automatic (ZF 8 speed etc) cars (BMW E93, F31).

Just curious as to whether you've been given any estimate of delivery. With i4's not scheduled to begin production until Q1 2024, have you been told when you might expect delivery?

 

[Tokion]

Just curious as to whether you've been given any estimate of delivery. With i4's not scheduled to begin production until Q1 2024, have you been told when you might expect delivery?

I signed the final contract and paid 10% of the locally set (Japan) purchase price in April 2022, about one year ago, and I was told delivery would be in May 2023 or later. I took this as meaning that delivery in May 2023 could not be guaranteed, and that the delivery most likely would take place later than this.

Recently there has been a local price increase, like in all Lotus markets around the world, but the local distributor has confirmed that there will be no price increase on already confirmed (Japan) orders (like I have), only on new orders from the time of the price increase.

I have been told by Lotus UK staff responsible for Asian markets that I4 FE production would start in Q1 or Q2 2023, or at least within summer 2023. I have not heard, or gotten any confirmation, that the production of I4 FE has been postponed to Q1 2024. As far as I am concerned, I have not received such information from any official Lotus source. My local distributor has also not told me that there will be such a delay.

 

[Drlonline]

I signed the final contract and paid 10% of the locally set (Japan) purchase price in April 2022, about one year ago, and I was told delivery would be in May 2023 or later. I took this as meaning that delivery in May 2023 could not be guaranteed, and that the delivery most likely would take place later than this.

Recently there has been a local price increase, like in all Lotus markets around the world, but the local distributor has confirmed that there will be no price increase on already confirmed (Japan) orders (like I have), only on new orders from the time of the price increase.

I have been told by Lotus UK staff responsible for Asian markets that I4 FE production would start in Q1 or Q2 2023, or at least within summer 2023. I have not heard, or gotten any confirmation, that the production of I4 FE has been postponed to Q1 2024. As far as I am concerned, I have not received such information from any official Lotus source. My local distributor has also not told me that there will be such a delay.

Hopefully your sources are correct on the 2023 delivery. I was basing my timing on an early March email from a well respected dealership in the U.S. (Gator Motorsport) which stated the following:
Production in 2023 will be entirely dedicated to fulfilling both batches of FE V6 Emira. Production of future variants will begin in 2024... The tentative timeline for 2024 is as follows: FE AMG I4 production January-April, Base V6 production May-December, and Base AMG I4 production August-December.
I believe this was referring to worldwide production, not just U.S. which we know is delayed further, but I'm not certain of that. I'm pulling for your projected timing, both for your earlier enjoyment as well as earlier reports on i4 performance for the rest of us. Good luck.

 

[Tokion]

Also worth noting to a Lotus fan is that DCTs are the heaviest transmissions out there, quite a bit more than a torque converter auto or a manual.

Nevertheless it is my impression that the Emira I4 with DCT is about 50kg lighter than the V6 manual version. Lotus has repeatedly said that the Emira I4 with DCT is the lightest version of the Emira family, weighing 1405kg. I have not seen weight data for the V6 with torque converter automatic, but I think it is heavier than the V6 with manual transmission. It would of course have been nice if there was a source for the weight of each of the three transmission types used in Emira. I am not entirely convinced that the DCT is heavier than the torque converter transmission, but I am also not arguing that this is not the case (for lack of data).

 

[JimH]

I signed the final contract and paid 10% of the locally set (Japan) purchase price in April 2022, about one year ago, and I was told delivery would be in May 2023 or later. I took this as meaning that delivery in May 2023 could not be guaranteed, and that the delivery most likely would take place later than this.

Recently there has been a local price increase, like in all Lotus markets around the world, but the local distributor has confirmed that there will be no price increase on already confirmed (Japan) orders (like I have), only on new orders from the time of the price increase.

I have been told by Lotus UK staff responsible for Asian markets that I4 FE production would start in Q1 or Q2 2023, or at least within summer 2023. I have not heard, or gotten any confirmation, that the production of I4 FE has been postponed to Q1 2024. As far as I am concerned, I have not received such information from any official Lotus source. My local distributor has also not told me that there will be such a delay.

USA i4's probably not likely until Q1 2024 earliest, given V6 FE delays, but UK, Europe and Asia currently planned to start production in Q2 2023 (probably press cars and demonstrators, i.e. very soon!) and ramping up customer deliveries from Q3 2023

 

[Fido]

Also worth noting to a Lotus fan is that DCTs are the heaviest transmissions out there, quite a bit more than a torque converter auto or a manual.

Someone on one of the other threads has detailed the different transmission weights: -
Aisin 6sp Auto - 90Kg
Aisin 6sp Manual - 87Kg
AMG 8G-DCT - 83.4Kg

 

[TomE]

Bear in mind for a full comparison you need to do:

• V6 engine + supercharger + manual gearbox + steel subframe + V6 fluids
• i4 engine + turbo + DCT gearbox + aluminium subframe + i4 fluids

There’s about 5kg difference in favour of the i4 on that basis.

The heaviest/lightest comparison of 1405kg vs 1458kg is i4 Base Edition with no options vs V6 First Edition (all options), so a lot of the difference is the options rather than engine/drivetrain.

 

[Concept24]

Bear in mind for a full comparison you need to do:

• V6 engine + supercharger + manual gearbox + steel subframe + V6 fluids
• i4 engine + turbo + DCT gearbox + aluminium subframe + i4 fluids

There’s about 5kg difference in favour of the i4 on that basis.

The heaviest/lightest comparison of 1405kg vs 1458kg is i4 Base Edition with no options vs V6 First Edition (all options), so a lot of the difference is the options rather than engine/drivetrain.

...and the weight of the driver!

 

[FederGigant]

Someone on one of the other threads has detailed the different transmission weights: -
Aisin 6sp Auto - 90Kg
Aisin 6sp Manual - 87Kg
AMG 8G-DCT - 83.4Kg

Can you share the source, because I very much doubt that those numbers are correct?

 

[TomE]

...and the weight of the driver!

And 50kg is the difference between a full and empty fuel tank or a petite passenger.

 

[Toomanyloti]

...and the weight of the driver!

this always makes me giggle. Shaving a few Kgs off, spending with diminishing returns and the driver like a shaved sasquatch

 

[Fido]

Can you share the source, because I very much doubt that those numbers are correct?

The numbers are quoted in several places already on this forum although I can’t find them now I’m actually looking! Anyway there are some external links:-

AWTF-80 SC - Wikipedia

en.wikipedia.org

List of what you get in the FE Emira

FYI, that technical drawing is showing the V6 version, not the I4 AMG. I kept pointing out that the Emira cannot be lighter than the Evora base on the info that Lotus had provided us. Emira are more focus on the daily driver, commuter car with better ergonomics. It actually shows both the V6...

www.lotustalk.com

That second one has several references and indicates the EA60 manual is 87kg

 

[Tokion]

USA i4's probably not likely until Q1 2024 earliest, given V6 FE delays, but UK, Europe and Asia currently planned to start production in Q2 2023 (probably press cars and demonstrators, i.e. very soon!) and ramping up customer deliveries from Q3 2023

But, will Lotus (very) soon show the completed I4 (FE) to the public (at Hethel and to the UK press). I would love to see Harry test it and compare to his V6 FE🥰😍🥰😍😇😇😇?????

I have this weird feeling that a major reason that we have not yet seen the I4 being shown to the public by Lotus, is that they wanted everyone to be focused on the V6 (especially manual) car.