[SSport16]

Originally Posted by SUMMIT WHITE SS

The paddles have a near one second delay, I don't consider that responsive. Was like that on both I drove, the Corvette is the same way. But, it's not a DCT, so I guess that should be expected, and I read about the delay in reviews. But as I said, when left in drive (as autos should), it was really good.

I don't really notice a delay, certainly not a 1 second delay...are they perfect, no of course no but the few times I have used them they were fine.

[SS 1LE]

Originally Posted by 08z51c6

A simple trans tune will fix that

A tune can not fix the delay.

Shift points, firmness, torque management yes...

[SS 1LE]

Originally Posted by SSport16

I don't really notice a delay, certainly not a 1 second delay...are they perfect, no of course no but the few times I have used them they were fine.

At WOT from when you pull the paddle, to when the car shifts, is about a second. Under normal driving this isn't noticeable.

[LesserO2Evils]

There is a delay. But it is certainly not a second long delay.

[SuperSound]

Are you letting off the gas anticipating it will not shift quickly? My 328i shifts extremely quick under WOT with the paddles. But if I let off even the slightest it hangs, my guess the computer is trying to figure out what I want to do.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[Curr]

Good read from Tadge Juechter (Chief engineer of the C7).

I would assume this applies in theory to the Gen 6, as well.

Question: Why does the time between depressing the paddle in manual mode and the Automatic Transmission shifting seem so long. Why can't it be instantaneous?

Answer:
First of all, we on Team Corvette want to wish everyone in the Corvette community and on the Corvette Forum a wonderful holiday and a safe and happy new year!

Now on to the answer:

Although shift speeds have been a priority in racing for a long time, it is a relatively new focus in the mass production auto industry. For decades we had basically two transmission choices; a traditional manual transmission where the time to shift was 100% dependent on the driver’s skill level, and a torque converter automatic where the vehicle hardware and calibration determined the shift timing and speed. The main focus on the automatics was a smooth shift with little driveline or customer disturbance. Yes, there were niche products that featured different set ups, so pardon me for the generalization.

Some performance cars started to offer automated manual transmissions that used a traditional clutch but did the work of shifting robotically, but my experience with those early units was that they were slow and lacked the finesse of a well-shifted manual driven by a skilled driver. Over time the shift quality and speed was improved and manufacturers started talking about shift times as an important performance vehicle characteristic. For the most part auto makers have moved away from automated manuals and use sophisticated planetary automatics or DCT’s to get the best shift speed and quality. This question focuses on shift speed, so I will leave the pros and cons of the two automatic transmission types for another day.

So why can’t down shifts be instantaneous? Well, there is the transmission hardware side that faces the physical challenge of transferring the torque from one set of gears to another set of gears. That is the time most manufacturers quote when discussing shift times. Those times have been improved over the years to very small fractions of a second and the Corvette is competitive with the best on that score. To be honest, we have put a higher priority on upshifts because they occur while accelerating and will contribute faster lap times. Downshifts typically occur when off-throttle and on the brakes, so a slower shift is far less likely to affect lap times. Regardless, up or down, our 8-speed automatic transmission is capable of extremely fast shift speeds.

The paddle shifters on Corvette are controlled by on-board computers just like many other functions on the car. They are “intelligent” devices that seek to improve the safety and controllability of the car. When the driver requests a downshift, the car does not blindly obey (the same is true for throttle inputs). It checks a multitude of parameters to verify that a shift can be done safely, without risk of damage to the car and without upsetting the vehicle dynamics. The control modules work to match the speed and torque of the engine to the future gear state. Note that there are a number of ECUs (Electronic Control Units) involved communicating in a coordinated way across an on-vehicle network, not just a computation done in a single processor. The larger the engine, the more inertia and the more challenging perfect matching is. I’m sure you know that an abrupt shift and resulting torque spike while cornering quickly can unsettle the car, so the algorithms for shifting will take that into account. In addition to how the car is being driven, ambient conditions, driver mode selected and other factors are taken into account. Even the break-in state of the transmission matters. Over time the transmission actually learns about itself and seeks to improve shift performance. All this intelligence takes computational time by the on-board processors. The throughput of those processors is dependent on the workload at the time of the shift, so the latency from shift command to shift execution can vary a bit.

All manufacturers are working to improve the shift speed and quality of their transmissions. I foresee ongoing improvement in this area.

One last side note: Some companies do something that we do not do. They move the tachometer needle to the new rpm on a shift faster than the engine actually achieves it. This bit of electronic trickery improves the perception of shift speed without actually changing it. Although it seems to be effective, we don't do it because it is inconsistent with our philosophy on Corvette to convey the most accurate information possible in our cluster displays.

[Brink]

I'm still on the fence about the A8. I know it's a great trans and is the quicker option but I know I will miss banging gears. Have any manual trans guys went to the A8, are you happy or wish you got the manual?

[checkmate427]

Originally Posted by Brink

I'm still on the fence about the A8. I know it's a great trans and is the quicker option but I know I will miss banging gears. Have any manual trans guys went to the A8, are you happy or wish you got the manual?

Wondering the same.

Always had manuals in my camaros, I think this one will be my first auto

[jimmypop13]

Originally Posted by Brink

I'm still on the fence about the A8. I know it's a great trans and is the quicker option but I know I will miss banging gears. Have any manual trans guys went to the A8, are you happy or wish you got the manual?

My last two cars were manuals. Ive had the A8 for a month now and no regrets yet

[Whis]

Originally Posted by Curr

Good read from Tadge Juechter (Chief engineer of the C7).

I would assume this applies in theory to the Gen 6, as well.

Question: Why does the time between depressing the paddle in manual mode and the Automatic Transmission shifting seem so long. Why can't it be instantaneous?

Answer:
First of all, we on Team Corvette want to wish everyone in the Corvette community and on the Corvette Forum a wonderful holiday and a safe and happy new year!

Now on to the answer:

Although shift speeds have been a priority in racing for a long time, it is a relatively new focus in the mass production auto industry. For decades we had basically two transmission choices; a traditional manual transmission where the time to shift was 100% dependent on the driver’s skill level, and a torque converter automatic where the vehicle hardware and calibration determined the shift timing and speed. The main focus on the automatics was a smooth shift with little driveline or customer disturbance. Yes, there were niche products that featured different set ups, so pardon me for the generalization.

Some performance cars started to offer automated manual transmissions that used a traditional clutch but did the work of shifting robotically, but my experience with those early units was that they were slow and lacked the finesse of a well-shifted manual driven by a skilled driver. Over time the shift quality and speed was improved and manufacturers started talking about shift times as an important performance vehicle characteristic. For the most part auto makers have moved away from automated manuals and use sophisticated planetary automatics or DCT’s to get the best shift speed and quality. This question focuses on shift speed, so I will leave the pros and cons of the two automatic transmission types for another day.

So why can’t down shifts be instantaneous? Well, there is the transmission hardware side that faces the physical challenge of transferring the torque from one set of gears to another set of gears. That is the time most manufacturers quote when discussing shift times. Those times have been improved over the years to very small fractions of a second and the Corvette is competitive with the best on that score. To be honest, we have put a higher priority on upshifts because they occur while accelerating and will contribute faster lap times. Downshifts typically occur when off-throttle and on the brakes, so a slower shift is far less likely to affect lap times. Regardless, up or down, our 8-speed automatic transmission is capable of extremely fast shift speeds.

The paddle shifters on Corvette are controlled by on-board computers just like many other functions on the car. They are “intelligent” devices that seek to improve the safety and controllability of the car. When the driver requests a downshift, the car does not blindly obey (the same is true for throttle inputs). It checks a multitude of parameters to verify that a shift can be done safely, without risk of damage to the car and without upsetting the vehicle dynamics. The control modules work to match the speed and torque of the engine to the future gear state. Note that there are a number of ECUs (Electronic Control Units) involved communicating in a coordinated way across an on-vehicle network, not just a computation done in a single processor. The larger the engine, the more inertia and the more challenging perfect matching is. I’m sure you know that an abrupt shift and resulting torque spike while cornering quickly can unsettle the car, so the algorithms for shifting will take that into account. In addition to how the car is being driven, ambient conditions, driver mode selected and other factors are taken into account. Even the break-in state of the transmission matters. Over time the transmission actually learns about itself and seeks to improve shift performance. All this intelligence takes computational time by the on-board processors. The throughput of those processors is dependent on the workload at the time of the shift, so the latency from shift command to shift execution can vary a bit.

All manufacturers are working to improve the shift speed and quality of their transmissions. I foresee ongoing improvement in this area.

One last side note: Some companies do something that we do not do. They move the tachometer needle to the new rpm on a shift faster than the engine actually achieves it. This bit of electronic trickery improves the perception of shift speed without actually changing it. Although it seems to be effective, we don't do it because it is inconsistent with our philosophy on Corvette to convey the most accurate information possible in our cluster displays.

Thank you!

[GMapologists]

Originally Posted by SUMMIT WHITE SS

The paddles have a near one second delay, I don't consider that responsive. Was like that on both I drove, the Corvette is the same way. But, it's not a DCT, so I guess that should be expected, and I read about the delay in reviews. But as I said, when left in drive (as autos should), it was really good.

I 100% agree with this statement. We both came to the same conclusion, because we have actually driven these cars. The lag when manually shifting is significant. The A8 should only be considered if you are unable to shift for yourself. The A8 is only decent when left in drive 100% of the time.

[huggercamaro21]

Originally Posted by GMapologists

I 100% agree with this statement. We both came to the same conclusion, because we have actually driven these cars. The lag when manually shifting is significant. The A8 should only be considered if you are unable to shift for yourself. The A8 is only decent when left in drive 100% of the time.

I disagree with everything you just said hahaha. It should 'only be considered if you cannot shift?' 'It's only decent when left in drive?'

[GMapologists]

Originally Posted by huggercamaro21

I disagree with everything you just said hahaha. It should 'only be considered if you cannot shift?' 'It's only decent when left in drive?'

It's not my opinion. It's a fact. The 6spd stick is excellent, but the A8 is terrible when manually shifted and it's only decent when left in drive 100% of the time. That's why I was forced to choose the manual for my 2016 1SS. If you go shift a PDK equipped car for yourself, then you will understand.

[MikeyCamaro]

The ZF A8 in the Challenger is near instantaneous on both up and downshifts and it's not a DCT so I don't see why this one couldn't be just as fast since the specs for the shift times seem comparable. I noticed that the Corvette A8 seemed to have quite a bit of shift lag from paddle tap to actual shift in this video (skip to 4:15). I don't think it's quite a full second but probably 500 to 750ms:

https://youtu.be/eoBrAydXK28

Using the paddles in my Challenger, it's instantaneous, or at least if there's any delay, it's undetectable and is probably close to the ~160ms spec. I think your shift spec for your A8 is close to the same so I don't understand why there would be such a delay in initiating the shift??? I would suspect tuning (maybe TQ management) could correct that?

Mike