Official Toyota & Lexus Future Powertrain/Product Discussion

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This is very random, but does anyone have any idea if for future F cars e.g - LC F, (holy crap, that is the only confirmed future F car. 😭), if Lexus will develop a dual-clutch transmission? Or will they just tune the 10-speed torque converter automatic to ben even quicker on the shifts and more aggressive in all possible areas?
It will use the 10-speed automatic transmission and crank the sh*t out of it to 11 (not 11 gears but like as in 11/10).
 

Joaquin Ruhi

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This is very random, but does anyone have any idea if for future F cars e.g - LC F, (holy crap, that is the only confirmed future F car. 😭), if Lexus will develop a dual-clutch transmission? Or will they just tune the 10-speed torque converter automatic to ben even quicker on the shifts and more aggressive in all possible areas?
For whatever their reasons, Toyota and Lexus have never been partial to dual-clutch transmissions. The closest they've come is the 5-speed SMT (Sequential Manual Transmission) option in the final, 3rd-gen Toyota MR2 and the 6-speed Aisin SA6 single-clutch automated manual in the Lexus LFA, but neither is a dual-clutch transmission.

In the case of the latter, the first part of my Lexus LFA review from 2009 contains this passage:

Those of you surprised by the LFA's relatively simple port-only fuel injection will be further shocked to hear that Lexus engineers chose to forego a dual-clutch arrangement such as that favored by Audi, Porsche and the Nissan GT-R in favor of a single clutch. A paragraph from the initial Lexus USA Newsroom Press Release succinctly offers the company's rationale: "The incredibly quick-revving nature of the LFA’s V10 engine demanded a single ultra-light and responsive clutch, a move that effectively ruled out a double-clutch transmission. The engineers also felt the ASG transmission’s positive and direct shift quality – as opposed to the almost artificial smoothness of current double-clutch transmissions – significantly enhanced the driving experience, making the driver aware of machined parts working together in harmony when changing gears for a satisfying sense of mechanical engagement".
 

Sebass

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I had a feeling, thank you for confirming it. I really do hope that they make the gears shorter, for a 10 speed they are too long right now. If I am correct, the only gears you need to use in the LC 500 from 0 mph up to its top speed, are gears 1 - 6. Gears 7 -10 are highway gears for better mpg, and I can't put it into words how important it is that on future F cars they make gears 1 - 7 shorter and make 7 a non-highway mpg gear. (Essentially have the transmission tuned so gears 1 - 7 are the gears you will need to rip the car from 0 to whatever its top speed will be). In fact, they may even need to make 8th gear a non-highway mpg gear.
 

Sebass

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For whatever their reasons, Toyota and Lexus have never been partial to dual-clutch transmissions. The closest they've come is the 5-speed SMT (Sequential Manual Transmission) option in the final, 3rd-gen Toyota MR2 and the 6-speed Aisin SA6 single-clutch automated manual in the Lexus LFA, but neither is a dual-clutch transmission.

In the case of the latter, the first part of my Lexus LFA review from 2009 contains this passage:
Thanks, the explanation of why the LFA has a single clutch makes sense, but I have heard a lot of people who have driven it say that the shifts feel to slow.
And... wait, wait, wait... You reviewed an LFA? did you drive one? If so, I am both highly jealous but also curious to know if you found the transmission slow.
 

ssun30

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DCT used to be popular since they have similar efficiency to manuals and fast shift speed, but modern ATs have shortened that gap considerably. Also torque converters have the added benefit of massive torque capacity, a desirable property for big turbocharged engines like the V8TT (likely to make over 900N.m). It makes no sense to develop a one-off DCT for like 50ms faster shifts.

I think LFA engineers once said they intentionally limited shift speed on the 6SMT so the driver can clearly feel the mechanical shift.

I had a feeling, thank you for confirming it. I really do hope that they make the gears shorter, for a 10 speed they are too long right now. If I am correct, the only gears you need to use in the LC 500 from 0 mph up to its top speed, are gears 1 - 6. Gears 7 -10 are highway gears for better mpg, and I can't put it into words how important it is that on future F cars they make gears 1 - 7 shorter and make 7 a non-highway mpg gear. (Essentially have the transmission tuned so gears 1 - 7 are the gears you will need to rip the car from 0 to whatever its top speed will be). In fact, they may even need to make 8th gear a non-highway mpg gear.
Four overdrives are not an overkill for a luxury cruiser like the LC. Those super long ODs are there to keep the engine at as low rpm as possible to cruise silently on the Autobahn at over 160km/h.

9 gears are enough to cover a 8.5:1 ratio spread (optimal for luxury cars), 8 is one gear too few, 10 provides that extra quietness at similar complexity to 9.

I don't see what you mean by 'non-highway mpg gear'. Modern AT ratios are not like the old 4/5ATs where there's a clear ratio gap between the drive gears and OD. The 10AT has very close 6-8 so there's no need to shorten the ratios. For the 2UR-GSE it helps to have closer ratios for gear 1-7, but the V8TT will have a very power band compared to the 2UR. What I'm saying is the 10AT is already a quite close ratio gearbox for a turbocharged engine.
 
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Joaquin Ruhi

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Thanks, the explanation of why the LFA has a single clutch makes sense, but I have heard a lot of people who have driven it say that the shifts feel to slow.
And... wait, wait, wait... You reviewed an LFA? did you drive one? If so, I am both highly jealous but also curious to know if you found the transmission slow.
That link I posted earlier was for Part 1 of my review (technical presentation and styling impressions). Yes, I was privileged to drive the LFA for 9 laps of the Homestead-Miami Speedway, an unforgettable experience. Those impressions are in Part 2 of my article.

My transmission impressions from there:

"The transaxle responded quickly and smoothly to both upshifts and downshifts from the paddles, and both the time-to-upshift beeps and rev matching "whompf" from the IS F are present and accounted for in the LFA, but they are muted by the glorious engine and exhaust sounds...

As I got underway, I noticed that the shifts in the black LFA felt far sharper and rougher than they did in the White Avenging Angel. Car-to-car variation? Possibly, but a far more likely explanation is that gearshift speeds can be adjusted in seven stages – from approximately 0.2 seconds for intense track work to 1.0 second for smooth cruising – using the Shift Speed Selection dial, and I'd venture a guess that Scott Pruett prefers the faster response time even at the cost of smoothness versus Hirose Nasure's slower but smoother shift setup. Perhaps it was my response to the transaxle shift setting, or perhaps the overconfidence that such an amazingly capable car inspires, but traces of sloppiness seeped into my driving, yet the LFA just motioned itself into the ideal line after the briefest rear twitch."
A link to my full driving impressions:
https://www.lexusfforum.com/forums/showthread.php?t=2065
 
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