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Dual clutch vs 8l90 tranny

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Old 12-15-2018, 05:00 PM
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Christi@n
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Default Dual clutch vs 8l90 tranny

Some rumors said that new c8 most likely will have a new dual clutch transmission...(also from nurburgring video hearing that shifting sound c8 looks already equipped with dct)
anyway is a little bit difficult to get cause even 8l90 has the throttle stop option when manually shifted, on other hand in video in some moments engine creeps when accelerating an this is typical from converter

what do you think about it?

IMO 8l90 or its succesor (as traditional automatic) or stick should be the 2 ways to go, i think there's no reason to get a dual clutch cause new at with converter already has very fast shifting times, plus they can make a great torque moltiplication that dct can not makes.

Last edited by Christi@n; 12-15-2018 at 05:15 PM.
Old 12-15-2018, 05:22 PM
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skank
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Christian
The Zerv CAD leaks showed a ZF DCT/Transaxle. The same exact unit that is in the Porsche 918. That is a very expensive unit. There are some on the forum here that think Tremec has built a DCT/Transaxle since Tremec is based in Michigan. Usually the CAD drawings are correct as they have to test for interference position between components. Check out this link below to see the transaxle and the CAD leaks.

https://www.corvetteforum.com/forums...post1596312478

http://www.tremec.com/index.php

Last edited by skank; 12-15-2018 at 05:46 PM.
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Old 12-15-2018, 05:36 PM
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Originally Posted by Christi@n
Some rumors said that new c8 most likely will have a new dual clutch transmission...(also from nurburgring video hearing that shifting sound c8 looks already equipped with dct) https://www.youtube.com/watch?v=RTXXoCg1F-k anyway is a little bit difficult to get cause even 8l90 has the throttle stop option when manually shifted, on other hand in video in some moments engine creeps when accelerating an this is typical from converter

what do you think about it?

IMO 8l90 or its succesor (as traditional automatic) or stick should be the 2 ways to go, i think there's no reason to get a dual clutch cause new at with converter already has very fast shifting times, plus they can make a great torque moltiplication that dct can not makes.
I don't understand what you are asking.
Old 12-15-2018, 05:46 PM
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skank
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Here's another view.

https://media.caranddriver.com.s3-we...s-1280x782.jpg

https://www.porscheatlantaperimeterparts.com/showAssembly.aspx?ukey_assembly=1272018& ukey_make=1058&ukey_model=20265&modelYea r=2015&ukey_category=20118

https://www.carscoops.com/2016/03/po.../#lg=1&slide=0

Last edited by skank; 12-15-2018 at 05:51 PM.
Old 12-15-2018, 05:52 PM
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Originally Posted by Christi@n
Some rumors said that new c8 most likely will have a new dual clutch transmission...(also from nurburgring video hearing that shifting sound c8 looks already equipped with dct) https://www.youtube.com/watch?v=RTXXoCg1F-k anyway is a little bit difficult to get cause even 8l90 has the throttle stop option when manually shifted, on other hand in video in some moments engine creeps when accelerating an this is typical from converter

what do you think about it?

IMO 8l90 or its successor (as traditional automatic) or stick should be the 2 ways to go, i think there's no reason to get a dual clutch cause new at with converter already has very fast shifting times, plus they can make a great torque multiplication that dct can not makes.
Listen at 0.46, 2.00 and 2.06. Sure sound like an unlocked torque converter spooling up to me, but no such 8 or 10 spd xaxle slush box exists that I know of. If you lifted briefly with a DCT or manual the RPM would remain constant at the same speed. Listen carefully I'd love to see a slush box and a 7 speed manual on the base OHV engined car. Maybe they can ask Dave Hill to search the parts bin in the truck division. If this can be achieved, the C8 models would cover every bodies needs. I don't know why the TC needs to unlock every time you lift off in track mode. With that and a brief unlock during upshifts, it would work nearly as well, if not better than a DCT especially below 30 mph.
Old 12-15-2018, 05:57 PM
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Christi@n
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Originally Posted by Zora.Info
I don't understand what you are asking.
hear some opinion about dct vs tc in corvette

i don't see any reason to swap from tc to dtc, cause even in at with tc gears are already engaged and is just necessary a clutck pack or brake movement to shift them

Last edited by Christi@n; 12-15-2018 at 06:05 PM.
Old 12-15-2018, 06:11 PM
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Originally Posted by Shaka
Listen at 0.46, 2.00 and 2.06. Sure sound like an unlocked torque converter spooling up to me, but no such 8 or 10 spd xaxle slush box exists that I know of. If you lifted briefly with a DCT or manual the RPM would remain constant at the same speed. Listen carefully I'd love to see a slush box and a 7 speed manual on the base OHV engined car. Maybe they can ask Dave Hill to search the parts bin in the truck division. If this can be achieved, the C8 models would cover every bodies needs. I don't know why the TC needs to unlock every time you lift off in track mode. With that and a brief unlock during upshifts, it would work nearly as well, if not better than a DCT especially below 30 mph.
0.46 2.00 and 2.06 are exactly what i was refering about
Old 12-15-2018, 06:18 PM
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Originally Posted by skank
Christian
The Zerv CAD leaks showed a ZF DCT/Transaxle. The same exact unit that is in the Porsche 918. That is a very expensive unit. There are some on the forum here that think Tremec has built a DCT/Transaxle since Tremec is based in Michigan. Usually the CAD drawings are correct as they have to test for interference position between components. Check out this link below to see the transaxle and the CAD leaks.

https://www.corvetteforum.com/forums...post1596312478

http://www.tremec.com/index.php
The Tremec above is not a Xaxle but I'm sure there will be a Tremec DCT for the C8. The Corvette boys sure spent a lot of time with both manufacturers and Mechatronics. The 918 has a Porsche designed and built PDK or DCT . I hope a manual will be available on the base car. GM has been working with Tremec and ZF for over 4 years now and since then, the Mexican based company has purchased the Belgium company, Hoerbiger Drivetrain Mechatronic who is the OEM xaxles for German makes. The gearbox above is ZF whom GM has also been talking to. With the Hoerbiger connection, a 6 speed manual is available for the 500hp OHV engine without a problem. We shall see soon enough.

https://www.corvetteforum.com/forums...post1598352357

Last edited by Shaka; 12-16-2018 at 02:01 PM.
Old 12-15-2018, 06:23 PM
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Originally Posted by Christi@n


hear some opinion about dct vs tc in corvette

i don't see any reason to swap from tc to dtc, cause even in at with tc gears are already engaged and is just necessary a clutck pack or brake movement to shift them
You must not be familiar with exotic cars. DCT is quite superior to torque converter. The shifts are much quicker, smoother, starting from a dead stop is smoother, etc.
Old 12-16-2018, 08:12 AM
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lt4obsesses
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I wonder if there will be transmission choice. Rather than automatic vs manual, it becomes traditional automatic vs DCT? It seems that there are pros and cons to each, and most of those depends upon how the car is used/driven. The DCT will add some expense, not only to build, but most likely to maintain and warranty, also is there a manufacturer, that can produce enough of them for this car, if were to be the only transmission available? ZF would be the most likely candidate.

But first and foremost, if they do at least offer a traditional automatic, it had better be the 10 speed they are putting the ZL1 Camaro, that is a great, smooth and fast transmission. Or at least an equivalent or better.

Last edited by lt4obsesses; 12-16-2018 at 08:14 AM.
Old 12-16-2018, 08:25 AM
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Originally Posted by lt4obsesses
I wonder if there will be transmission choice. Rather than automatic vs manual, it becomes traditional automatic vs DCT? It seems that there are pros and cons to each, and most of those depends upon how the car is used/driven. The DCT will add some expense, not only to build, but most likely to maintain and warranty, also is there a manufacturer, that can produce enough of them for this car, if were to be the only transmission available? ZF would be the most likely candidate.

But first and foremost, if they do at least offer a traditional automatic, it had better be the 10 speed they are putting the ZL1 Camaro, that is a great, smooth and fast transmission. Or at least an equivalent or better.
They cannot use an existing transmission since the car uses a transaxle. To use an existing transmission they would have to go with a C7 type configuration where the transmission bolts up directly to the differential. With a transaxle the transmission and differential are combined in one unit. So whatever they use will be brand new and not an existing component.
Old 12-16-2018, 10:06 AM
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Originally Posted by Zora.Info
You must not be familiar with exotic cars. DCT is quite superior to torque converter. The shifts are much quicker, smoother, starting from a dead stop is smoother, etc.
Since you know so much about DCTs, you know they use two wet multi-plate clutches in a clutch-to-clutch shifting architecture. They have a separate hydraulic pump to provide pressurized oil to engage the clutch on each shift.

Amazingly, the torque converter automatic 8L90 has five wet multi-plate clutches in a clutch-to-clutch shifting architecture, both technologies shift at the same speed so that's a tie. The torque converter is several orders of magnitude smoother as it has a Pulse-Width Modulated clutch in the torque converter that "locks" and "unlocks" the torque converter to allow as much as 100 RPM speed difference between the input and output shafts of the torque converter, an overwhelming victory for the torque converter. From a dead stop, the DCT can get confused by inputs from the driver and become balky as well as only transferring torque on a one-for-one basis. The torque converter never gets confused or balky based on inputs from the driver but the best part is the torque converter multiplies the torque at low speed by a factor of two as well as allowing the engine to operate higher on its torque curve, starting froma dead stop with a torque converter is superior to a DCT giving another overwhelming victory to the torque converter automatic.

You're certainly entitled to your opinion but the facts are the facts. In the end, the DCT is an automatic transmission without the torque converter...they left out the best part!

BTW, you'll find DCT transmissions in economy cars today, they aren't just for exotics. I had a 2015 Citroen C3 when I lived in Spain with a 1.4L diesel engine and a DCT...the DCT was the worst part of the car. On the other hand, I rented an Audi with DCT on the island of Crete and it was like the transmission was connected to my brain.

Last edited by glass slipper; 12-16-2018 at 10:11 AM.
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Old 12-16-2018, 10:27 AM
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Originally Posted by Zora.Info
You must not be familiar with exotic cars. DCT is quite superior to torque converter. The shifts are much quicker, smoother, starting from a dead stop is smoother, etc.
Owning a DCT car I have to disagree in part. Yes the DCT shifts are much faster, but in all honesty, my Audi A6, non DCT, is just as smooth both moving and from a stop.
Old 12-16-2018, 11:36 AM
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Why does everybody think the 10L90 from the Camaro can go into the Corvette??? It is a traditional longitudinal transmission, it bolts up to the engine, connects to a driveshaft which goes back to the rear differential. They can not stuff that into the Corvette, let alone the ME.
Old 12-16-2018, 11:50 AM
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Doubt that Chevy would produce a transmission for a one only platform. Cost would be the factor.
Old 12-16-2018, 12:10 PM
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Originally Posted by feeder82
Doubt that Chevy would produce a transmission for a one only platform. Cost would be the factor.
Who are you replying to?
Old 12-16-2018, 12:11 PM
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Originally Posted by feeder82
Doubt that Chevy would produce a transmission for a one only platform. Cost would be the factor.
They will have to as they don’t have a transaxle in their parts bin. They will have t secure it from a third party.

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Old 12-16-2018, 12:14 PM
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Originally Posted by Tom73

They will have to as they don’t have a transaxle in their parts bin. They will have t secure it from a third party.
It has been said it will be from Tremec.
Old 12-16-2018, 12:23 PM
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Originally Posted by Christi@n


0.46 2.00 and 2.06 are exactly what i was refering about
Very subtle, I must say. You must be an engineer to notice this. It seems that GM may have some fueling issues to work out when going from "Throttle-off to partial throttle-on."
Or, this may be built within the tune to reduce wheel spin coming out of turns. (Many a Corvette are in junkyards because of their patented "tail-snap.")
Old 12-16-2018, 12:36 PM
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Technical specs on the rumored Tremec DCT transaxle:
https://www.corvetteforum.com/forums...post1598352357


In 2012, Tremec aquired a Belgian company, Hoerbiger Drivetrain Mechatronics BVBA, that specializes in "DCT technology" for exotic sports cars.

From Car and Driver:
Four years ago, Chevrolet Corvette manual-transmission supplier Tremec aspired to achieve greater global reach. Instead of reinventing the helical gear to enter the thriving dual-clutch automatic transmission (DCT) business, this Mexico-based manufacturer simply shopped for a company that already possessed the expertise it needed. Tremec was drawn to Hoerbiger Drivetrain Mechatronics because of that Belgian firm’s proven relationships with Mercedes-AMG, Ferrari, and McLaren. A deal was cut and Tremec now owns Hoerbiger lock, stock, and gear hobber.

The prodigy from these two parental units is Tremec’s TR-9007 family of dual-clutch automatics that can be assembled in rear-drive, all-wheel-drive, and transaxle configurations.
Since the Corvette team already have a close relationship with Tremec, using their manual transmissions, it's my belief that a Tremec DCT transaxle is all but certain in the C8.

In 2016 Tremec invested $54 million in a HQ/tranny manufacturing plant in Wixom, MI. They're preparing to manufacture Corvette DCT's right in MI, close to the C8 development team at GM's Warren technical center.

Last edited by Zaro Tundov; 12-16-2018 at 12:57 PM.


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