C7 Zo6

[gthal]

Originally Posted by Petros

You must have forgotten to read the part where the Z06 "autoshitbox" will shift faster than a DCT. Oh and the Z06 will crush the 458 on the track.

As mentioned, 100ms for a DCT vs 80 ms upshift for a new auto is effectively the same thing... that is, effectively "instant" in real life.

The jury is out on downshift speed (GM has not commented to my knowledge) and that will matter as much or more in performance driving.

The auto in the Z will be amazing, that I'm confident in. Whether it is "better" than the best DCT's is to be determined but my bet is it won't be for track use. For street use, maybe...

[Petros]

Originally Posted by gthal

As mentioned, 100ms for a DCT vs 80 ms upshift for a new auto is effectively the same thing... that is, effectively "instant" in real life.

The jury is out on downshift speed (GM has not commented to my knowledge) and that will matter as much or more in performance driving.

The auto in the Z will be amazing, that I'm confident in. Whether it is "better" than the best DCT's is to be determined but my bet is it won't be for track use. For street use, maybe...

Why does downshift speed matter so much? Typically you're downshifting while braking and off the throttle, so a few extra milliseconds in downshift time shouldn't really affect the overall lap time.

[gthal]

Originally Posted by Petros

Why does downshift speed matter so much? Typically you're downshifting while braking and off the throttle, so a few extra milliseconds in downshift time shouldn't really affect the overall lap time.

On a track, downshift speed is as or more important in my opinion. You are braking and downshifting at the same time while at the limit of traction... the faster that happens and the more direct it is, the more balanced that car remains and the entire process is better. It is the reaction time of the downshift at the limit that is important.

Also, in my experience, the braking zones are where good cars make up a lot of ground in time.

The car not reacting well on downshifts is actually bothersome (to me anyway) in aggressive driving much more so than anything related to upshift speed.

[Groundpilot]

Originally Posted by gthal

As mentioned, 100ms for a DCT vs 80 ms upshift for a new auto is effectively the same thing... that is, effectively "instant" in real life.

The jury is out on downshift speed (GM has not commented to my knowledge) and that will matter as much or more in performance driving.

The auto in the Z will be amazing, that I'm confident in. Whether it is "better" than the best DCT's is to be determined but my bet is it won't be for track use. For street use, maybe...

I think you would lose that bet. Do you really think that GM is going to put auto tranny in Z06 for the first time ever and it wont be for track use?
I seriously doubt that. They didnt mention anything about downshift speed as far as i know as well, but dont forget, the whole package is still under development. Downshift speed is as important in racing conditions as upshift, so i am sure they will at least match that with dct or pdk.

[pkimM3r]

Originally Posted by Petros

Funny how when someone says they prefer the manual because it has a more direct connection to the car, the DCT fanboys brag about how much faster the shifting is with the DCT compared to the outdated 3 pedal set up. And now when a conventional auto with a torque converter is claimed to shift even faster than a DCT, the DCT fanboys pull an about face and the slower shifting DCT is now better because it has a more direct connection to the car?!?!?!!

The zf right now is the gold standard. Its pretty good. How much better can the new auto be? Its good but there are still issues with it.

I still dont understand how a torque converter can rev match. Does it go into neutral for 0.000001 seconds, blips and then engage again? I'm asking because i dont know.

[pkimM3r]

Originally Posted by Petros

You must have forgotten to read the part where the Z06 "autoshitbox" will shift faster than a DCT. Oh and the Z06 will crush the 458 on the track.

Ok now calm down. Youre talking about a car that has been out for how long now vs one still in development. Wait for the 458 successor. Then talk.

I drive a manual and the dct was a great experience. I just have doubts on an autoshitbox until it is proven. There are dct gtrs out there that handle 1000hp and whatever ridiculous amount of torque they put out under launch control for strictly drag racing so the it cant handle torque is a moot point.

[Brosef]

Originally Posted by Groundpilot

I think you would lose that bet. Do you really think that GM is going to put auto tranny in Z06 for the first time ever and it wont be for track use?
I seriously doubt that. They didnt mention anything about downshift speed as far as i know as well, but dont forget, the whole package is still under development. Downshift speed is as important in racing conditions as upshift, so i am sure they will at least match that with dct or pdk.

I highly doubt that it will match the DCT and PDK in downshift speed (I even doubt that it will be faster in upshift speed).

and he never said the Z06 auto won't be good for track use. he just said it won't be as good as BMW's DCT or Porsche's PDK on track, but would be slightly better for everyday driving.

I'm not sure how much time you've spent driving either the DCT or PDK, but there is absolutely nothing left to be desired in faster upshift speeds. it's absolutely instantaneous. and I am highly confident that the auto will not match the feeling of crisp directness that the DCT's provide. banging through gears in S6 on the DCT feels so good. that's why it successfully lured so many people away from manuals.

[pkimM3r]

Originally Posted by Petros

You must have forgotten to read the part where the Z06 "autoshitbox" will shift faster than a DCT. Oh and the Z06 will crush the 458 on the track.

Also dont get upset i was one of the first to say holy Jesus Christ have you seen the new z06?! On here.

[Groundpilot]

Originally Posted by Brosef

I highly doubt that it will match the DCT and PDK in downshift speed (I even doubt that it will be faster in upshift speed).

and he never said the Z06 auto won't be good for track use. he just said it won't be as good as BMW's DCT or Porsche's PDK on track, but would be slightly better for everyday driving.

I'm not sure how much time you've spent driving either the DCT or PDK, but there is absolutely nothing left to be desired in faster upshift speeds. it's absolutely instantaneous. and I am highly confident that the auto will not match the feeling of crisp directness that the DCT's provide. banging through gears in S6 on the DCT feels so good. that's why it successfully lured so many people away from manuals.

DCT on the track is absolutely fenomenal. I have two cars with it and i track both.
If new Z06 comes with dct that we know, i would be very happy. But, if there will be only two choices, manual and their specifically designed 8 speed auto tranny, i would chose auto.
Even if downshifts are slightly slower than DCT or PDK, it should still outperform manual on the track, as i dont think anyone can change gears manually as fast a the new auto transmission will. They said upshifts will be slightly faster than PDK. That should more than make up for slightly slower downshifts.

[///M Power-Belgium]

Interior......don't think our ///M3's have this !
Check this out....

[FormulaMMM]

That performance data recorder is soooooo cool

[hellrotm]

USA vs Europe

[///M Power-Belgium]

Originally Posted by BlackJetE90

USA vs Europe

Great video and the man can drive the C7 for sure !
The big surprise is that it is also faster than the Carrera S ,and this is only the C7 with 460 HP !
What i want to say this threat is about the new Z06 with about 620 HP !!! Witch is 160 HP more......
So a Vette from this new generation(ZO6) with 620 HP and with a handling that is even better than the C7 is for me the new ...Ultimate driving machine !
To beat this car a car will be needed that costs the price of the Z06 x 5 !
I feel sorry that i live in Belgium because of the fiscale HP of the Vette it's now about 10,000 Euro's first time in traffic taxes ( $ 13,635 USD + yearly drivers taxes ! ) and without insurance !
Conclusion.........
God bless America and that's for sure
When i see now all the video's about the Corvette Z06 i start to think....and i don't like to say it, but i will and on the American way....the ///M BMW's along this car start to look... like pussy wagons !

[1MOREMOD]

Originally Posted by FormulaMMM;*****642

That performance data recorder is soooooo cool

yes very cool to have that integrated and get all the data along with it.

[Ashley Schaeffer BMW]

LOL Chevy is making some of you Euro-philes very very nervous. Gotta love it

[Groundpilot]

I saw this post on corvette forum. Explains the difference between the new generation of auto tranny and DCT. I hope they dont mind this, that i am posting it here



"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.

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.
Oh yeah, one more thing. For those who wonder, what is 8L90, its an 8 speed automatic transmission that will be used in c7 z06

[swamp2]

Originally Posted by Groundpilot

I saw this post on corvette forum. Explains the difference between the new generation of auto tranny and DCT. I hope they dont mind this, that i am posting it here



"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.

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.
Oh yeah, one more thing. For those who wonder, what is 8L90, its an 8 speed automatic transmission that will be used in c7 z06

There is some good perspective and I largely agree with the post, however, a few of the details are completely wrong. One of the early best modern automatic was the ZF 6 speed in the Jaguar XK in 2006. This unit shifted fast, had a good auto and manual mode, full lock up above 2000 rpm and very fast shift times comparable to a DCT.

• On take off a modern automatic transmission does not multiply torque. Gears multiply torque not the clutch. The latter part of that statement is true, the automatic will very likely best a DCT at takeoff. However, it is really all about the software, either DCT or automatic. A DCT could certainly be programmed for more slip allowing the rpms to rise faster. That might cause unacceptable wear though.
• There is no reason the believe this new automatic transmission will best the DCT in "driveability" whatever that means (comfort perhaps...). DCTs are already pretty silky smooth with the best automatics having perhaps a very slight edge at low speeds.
• "computer second guessing" - ugh, rubbish. Both modern autos and DCTs have fully manual and fully automatic modes with not much disticntion there unless they do silly things like force shifts at redline in manual mode.
• "worry about being in the wrong gear..." is also rubbish. The DCTs I've driven typically have a wonderful predictive capability to preengage the appropriate "next" gear.

The lines are really blurring between high end automatics and DCTs from a performance perspective. Interestingly enough, they are entirely different beasts on the inside.

[Petros]

Originally Posted by swamp2

There is some good perspective and I largely agree with the post, however, a few of the details are completely wrong. One of the early best modern automatic was the ZF 6 speed in the Jaguar XK in 2006. This unit shifted fast, had a good auto and manual mode, full lock up above 2000 rpm and very fast shift times comparable to a DCT.

• On take off a modern automatic transmission does not multiply torque. Gears multiply torque not the clutch. The latter part of that statement is true, the automatic will very likely best a DCT at takeoff. However, it is really all about the software, either DCT or automatic. A DCT could certainly be programmed for more slip allowing the rpms to rise faster. That might cause unacceptable wear though.
• There is no reason the believe this new automatic transmission will best the DCT in "driveability" whatever that means (comfort perhaps...). DCTs are already pretty silky smooth with the best automatics having perhaps a very slight edge at low speeds.
• "computer second guessing" - ugh, rubbish. Both modern autos and DCTs have fully manual and fully automatic modes with not much disticntion there unless they do silly things like force shifts at redline in manual mode.
• "worry about being in the wrong gear..." is also rubbish. The DCTs I've driven typically have a wonderful predictive capability to preengage the appropriate "next" gear.

The lines are really blurring between high end automatics and DCTs from a performance perspective. Interestingly enough, they are entirely different beasts on the inside.

actually torque converters do multiply torque at low speeds http://www.hardtail.com/techtips/torqueconverters.html

[swamp2]

Originally Posted by Petros

actually torque converters do multiply torque at low speeds http://www.hardtail.com/techtips/torqueconverters.html

Correct, I misspoke, you can't get more power to the wheels than you have power at the crank and power is what gives you acceleration, not torque... I also meant torque converter not clutch, d'oh... However, there are considerable losses from the conditions near stall when torque is multiplied, which will get you less power to the wheels.

[bruce.augenstein@comcast.]

Originally Posted by gthal

On a track, downshift speed is as or more important in my opinion. You are braking and downshifting at the same time while at the limit of traction... the faster that happens and the more direct it is, the more balanced that car remains and the entire process is better. It is the reaction time of the downshift at the limit that is important.

Also, in my experience, the braking zones are where good cars make up a lot of ground in time.

The car not reacting well on downshifts is actually bothersome (to me anyway) in aggressive driving much more so than anything related to upshift speed.

Not to say that quicker downshift speeds aren't a plus, but I spent about eight out of fourteen years on track in cars that weren't very responsive to the gas (i.e. - turbos), and never felt that they were a problem. You just hit the gas here instead of there, plus the turbo makes you smooth.

For downshifting, pull the paddle here instead of there, and you're good to go.

No?

I figure around three laps into any given road course, and you've got it.

No?

Bruce

[Groundpilot]

Originally Posted by bruce.augenstein@comcast.

Not to say that quicker downshift speeds aren't a plus, but I spent about eight out of fourteen years on track in cars that weren't very responsive to the gas (i.e. - turbos), and never felt that they were a problem. You just hit the gas here instead of there, plus the turbo makes you smooth.

For downshifting, pull the paddle here instead of there, and you're good to go.

No?

I figure around three laps into any given road course, and you've got it.

No?

Bruce

Yes. I agree. Good driver can always adjust to what he has.
We had good discussion in this thread about manual vs modern auto transmission and DCT/PDK. They are all good in good hands. The real question is, which one is better, faster on the track driven in the same conditions by the same driver.
That post that i found in corvette forum, was written by an engeneer, who knows whats up, and it looks like new 8 speed auto, that will be used in c7 z06, will function the same way but differently, and according to him, shift speed will be as good or even better than DCT, not to mention better driveability.

[gthal]

Originally Posted by Groundpilot

Yes. I agree. Good driver can always adjust to what he has.

Correct, they can... but they shouldn't have to

At the end of the day, as I've said, I'm very confident GM will get this transmission correct. Probably on the downshifts too. However, until cars are available and tested, it will be speculation either way IMO. I believe if GM wasn't confident they could make the auto everything they promised it will be then they wouldn't have offered it on the Z06.