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Originally Posted by Caddylac10
(Post 1585893336)
Please do some research so you can atleast sound intelligent. If anything, a stick is the slushbox because it's far slower. 150 millisecond shifts are as fast as the eye can blink. That's what current 8 speeds are capable of with locking torque converters too. The Z's 8 speed may be even better.
It's still an automated paddle shift transmission just like a DCT with notable NVH characteristics too. If you prefer a manual that's fine but there is no debate about which one offers better performance. |
Originally Posted by MHaynes772
(Post 1585892989)
The Lamborghini Aventador doesn't have DCT, it uses an automatic gearbox. They're not all bad. We should just hold out until Monday to see the details.
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Originally Posted by 05dsom
(Post 1585894468)
A choice of either (or all three--hahahaha, no way!) is the best course of action for GM
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Originally Posted by 32valves
(Post 1585892792)
Why wouldn't GM just put a DCT in the Z06 instead of trying to make it look like one? They are obviously embarrassed about this or they wouldn't try to make it look like a DCT. I don't get it...DCTs have all the benefits of a manual and automatic at the same time. Slushboxes don't belong in supercars, period.
A DCT has two multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The 8L90 has multiple multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The same exact thing just different. There is no reason the 8L90 can't shift as fast as a DCT...they both use multi plate wet clutches and a hydraulic pump in conjunction with proportional "solenoid" valves that control the speed of the clutch engagement/shift. I like the term "torque converter MCT" for the 8L90...it has more than two clutches so DCT wouldn't be proper. Plus, more is better. :D Any standing start contest will be won handily by the 8L90 with the torque converter multiplying torque and letting the engine get up on top of its HP curve faster. They weigh about the same and efficiency will be about the same but the 8L90 will be smaller. The 8L90 will kick any DCT to the curb when it comes to drivability and you don't have to worry about the computer second guessing what you want to do. You also don't have to worry about being in the wrong gear all of a sudden since the DCT can only pre-select one gear...all gears are engaged all of the time in the 8L90. I think if people took the time to understand 21st century automatics, we wouldn't have so many naysayers. Hopefully there will be plenty of info at the reveal but it's the proverbial "you can lead a horse to water" all over again...you can't drown them because they breathe through their butt. :lol: |
Originally Posted by glass slipper
(Post 1585894798)
"Slushboxes" are from the '50s when they had fluid couplers. Those were replaced by torque converters in the '60s, lockup torque converters in the '70s, pulse width modulated (PWM) lockup torque converters in the '90s, and the 2000s brought us multi-disc PWM lockup torque converters capable of transmitting the maximum power of high performance engines in lockup mode. The 6L80 torque converter goes into lockup in 2nd gear and I'm sure the 8L90 will too. The PWM feature "pulses" the lockup clutch hydraulic pressure to achieve as much as 80-100 RPM "slippage" between the input/output of the torque converter at low RPM cruise to dampen engine vibrations due to low frequency power pulses from individual piston power strokes. The modern day torque converter has nothing in common with the old "slushbox" fluid coupler...welcome to the 21st century.
A DCT has two multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The 8L90 has multiple multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The same exact thing just different. There is no reason the 8L90 can't shift as fast as a DCT...they both use multi plate wet clutches and a hydraulic pump in conjunction with proportional "solenoid" valves that control the speed of the clutch engagement/shift. I like the term "torque converter MCT" for the 8L90...it has more than two clutches so DCT wouldn't be proper. Plus, more is better. :D Any standing start contest will be won handily by the 8L90 with the torque converter multiplying torque and letting the engine get up on top of its HP curve faster. They weigh about the same and efficiency will be about the same but the 8L90 will be smaller. The 8L90 will kick any DCT to the curb when it comes to drivability and you don't have to worry about the computer second guessing what you want to do. You also don't have to worry about being in the wrong gear all of a sudden since the DCT can only pre-select one gear...all gears are engaged all of the time in the 8L90. I think if people took the time to understand 21st century automatics, we wouldn't have so many naysayers. Hopefully there will be plenty of info at the reveal but it's the proverbial "you can lead a horse to water" all over again...you can't drown them because they breathe through their butt. :lol: One of the best posts on the subject that I have read. |
Originally Posted by glass slipper
(Post 1585894798)
"Slushboxes" are from the '50s when they had fluid couplers. Those were replaced by torque converters in the '60s, lockup torque converters in the '70s, pulse width modulated (PWM) lockup torque converters in the '90s, and the 2000s brought us multi-disc PWM lockup torque converters capable of transmitting the maximum power of high performance engines in lockup mode. The 6L80 torque converter goes into lockup in 2nd gear and I'm sure the 8L90 will too. The PWM feature "pulses" the lockup clutch hydraulic pressure to achieve as much as 80-100 RPM "slippage" between the input/output of the torque converter at low RPM cruise to dampen engine vibrations due to low frequency power pulses from individual piston power strokes. The modern day torque converter has nothing in common with the old "slushbox" fluid coupler...welcome to the 21st century.
A DCT has two multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The 8L90 has multiple multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The same exact thing just different. There is no reason the 8L90 can't shift as fast as a DCT...they both use multi plate wet clutches and a hydraulic pump in conjunction with proportional "solenoid" valves that control the speed of the clutch engagement/shift. I like the term "torque converter MCT" for the 8L90...it has more than two clutches so DCT wouldn't be proper. Plus, more is better. :D Any standing start contest will be won handily by the 8L90 with the torque converter multiplying torque and letting the engine get up on top of its HP curve faster. They weigh about the same and efficiency will be about the same but the 8L90 will be smaller. The 8L90 will kick any DCT to the curb when it comes to drivability and you don't have to worry about the computer second guessing what you want to do. You also don't have to worry about being in the wrong gear all of a sudden since the DCT can only pre-select one gear...all gears are engaged all of the time in the 8L90. I think if people took the time to understand 21st century automatics, we wouldn't have so many naysayers. Hopefully there will be plenty of info at the reveal but it's the proverbial "you can lead a horse to water" all over again...you can't drown them because they breathe through their butt. :lol: Now that we've established that SLUSH is involved in either a TC or DCT auto transmission, the question is, which performs better and where is the technology headed next. Most mechanical engineers, (of whom there are apparently just a handful on this forum - including me), understand that the technology in controls, actuation and multi-plate clutches will, inevitably, make the advanced TC auto a much better choice than a DCT for a number of reasons. The simplest is that the TC auto is lighter, can multiply the engine torque at start and low speeds, and is much more flexible than a sequential or a DCT - the computer simply has more "knobs" to turn. The A6 in my Z51 works great. It's smooth in Touring and shifts as fast I could with an M7 in Sport or Track. I'm certain that the A8 will work even better. I'm willing to bet that the new Z06 with the A8 will put the vaunted 911 (991) GT3 back on the trailer with out breaking a sweat. And when it does, what will the DCT zealots say then ? It will "feel" faster if only it had a DCT ? Give me a break. |
Finally, an intelligent thread.
I had all but given up on this board. |
Nice to see the understanding of these new autos is starting to sink in... I'm a die hard manual guy, but I'd probably buy one of these new 8-speeds :yesnod:
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Two greats posts in one thread. We are blessed!
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Originally Posted by glass slipper
(Post 1585894798)
"Slushboxes" are from the '50s when they had fluid couplers. Those were replaced by torque converters in the '60s, lockup torque converters in the '70s, pulse width modulated (PWM) lockup torque converters in the '90s, and the 2000s brought us multi-disc PWM lockup torque converters capable of transmitting the maximum power of high performance engines in lockup mode. The 6L80 torque converter goes into lockup in 2nd gear and I'm sure the 8L90 will too. The PWM feature "pulses" the lockup clutch hydraulic pressure to achieve as much as 80-100 RPM "slippage" between the input/output of the torque converter at low RPM cruise to dampen engine vibrations due to low frequency power pulses from individual piston power strokes. The modern day torque converter has nothing in common with the old "slushbox" fluid coupler...welcome to the 21st century.
A DCT has two multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The 8L90 has multiple multi plate wet clutches that are hydraulically applied/released in a clutch to clutch architecture. The same exact thing just different. There is no reason the 8L90 can't shift as fast as a DCT...they both use multi plate wet clutches and a hydraulic pump in conjunction with proportional "solenoid" valves that control the speed of the clutch engagement/shift. I like the term "torque converter MCT" for the 8L90...it has more than two clutches so DCT wouldn't be proper. Plus, more is better. :D Any standing start contest will be won handily by the 8L90 with the torque converter multiplying torque and letting the engine get up on top of its HP curve faster. They weigh about the same and efficiency will be about the same but the 8L90 will be smaller. The 8L90 will kick any DCT to the curb when it comes to drivability and you don't have to worry about the computer second guessing what you want to do. You also don't have to worry about being in the wrong gear all of a sudden since the DCT can only pre-select one gear...all gears are engaged all of the time in the 8L90. I think if people took the time to understand 21st century automatics, we wouldn't have so many naysayers. Hopefully there will be plenty of info at the reveal but it's the proverbial "you can lead a horse to water" all over again...you can't drown them because they breathe through their butt. :lol: Thanks for any further insight. |
Originally Posted by 32valves
(Post 1585892792)
Why wouldn't GM just put a DCT in the Z06 instead of trying to make it look like one? They are obviously embarrassed about this or they wouldn't try to make it look like a DCT. I don't get it...DCTs have all the benefits of a manual and automatic at the same time. Slushboxes don't belong in supercars, period.
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Originally Posted by thebishman
(Post 1585896369)
Great post. Quick ?: Can 8L90 be made to avoid heatsoak on the road course in high ambient temps for approximately 25 minutes? Its my only concern.
Thanks for any further insight. |
Originally Posted by dcbingaman
(Post 1585895519)
At last, a poster who understands transmissions, as opposed to the raft of DCT zealots who don't seem to realize that the DCT is 50 years old and is not the only way to get the job done. All DCT's with any power handling capability use WET clutches - they depend on SLUSH to engage the engine and the drivetrain.
Now that we've established that SLUSH is involved in either a TC or DCT auto transmission, the question is, which performs better and where is the technology headed next. Most mechanical engineers, (of whom there are apparently just a handful on this forum - including me), understand that the technology in controls, actuation and multi-plate clutches will, inevitably, make the advanced TC auto a much better choice than a DCT for a number of reasons. The simplest is that the TC auto is lighter, can multiply the engine torque at start and low speeds, and is much more flexible than a sequential or a DCT - the computer simply has more "knobs" to turn. The A6 in my Z51 works great. It's smooth in Touring and shifts as fast I could with an M7 in Sport or Track. I'm certain that the A8 will work even better. I'm willing to bet that the new Z06 with the A8 will put the vaunted 911 (991) GT3 back on the trailer with out breaking a sweat. And when it does, what will the DCT zealots say then ? It will "feel" faster if only it had a DCT ? Give me a break. |
Originally Posted by JustinStrife
(Post 1585892799)
Someone get this man a tissue. Maybe a box of tissues.
So much hurt on this forum. For an optional feature, on an expensive car, that no-one is forcing anyone to buy. If it sells.. its because thats what people wanted. |
Originally Posted by tslick98
(Post 1585896390)
it aint a supercar. it's a chevy
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Originally Posted by Daekwan06
(Post 1585896992)
We are way beyond tissues at this point.. and after tomorrow's official announcement.. they are going to need to start handing out tampons.
So much hurt on this forum. For an optional feature, on an expensive car, that no-one is forcing anyone to buy. If it sells.. its because thats what people wanted. |
Originally Posted by Snorman
(Post 1585893333)
Dig in, because there is going to be a long year if they start building later in 2014.
We're going to be hearing how GM cheaped out and should have offered a DCT. We're going to be told that they should have revised the rear fascia to appease the "majority" of people who don't like the rear of the C7 (this includes that it should have had round taillights). We're going to hear that they screwed up by not offering a bigger cube NA engine. It's going to be bench raced to death against the C6 Z06 and ZR1, very likely with many owners of the latter telling us that it's not going to be as fast and GM is lying about its performance numbers. Basically, the entire C7-Detractors Playbook will be brought out in full force. :yesnod: S. |
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