Michelin Z51 A/S ZP release date
#21
Instructor
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We saw the actual tire at Spring Mountain in August. They said that it was a run flat, and there was no mention of manual vs automatic.
The only stipulation was that the ZO6 versions of the all-season were coming later.
No date specified.
Note that while they were showing the tire, the Michelin folks were there taking the 2 day course. Guessing that they brought it with them.
The only stipulation was that the ZO6 versions of the all-season were coming later.
No date specified.
Note that while they were showing the tire, the Michelin folks were there taking the 2 day course. Guessing that they brought it with them.
#22
Racer
There are no AS 3+ run flat tires!
Just like there is no automatic rev match!
#23
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#24
actually there is a thread stating the Auto's do rev match in track mode shrug whatever you say dude
#25
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I have these tires for my Stingray (18 and 19s). The price was $1,250 at Discount Tires. They had a touchless system for install and the latest balance system. I had them rotated after 7,000 miles. Remember that the tires are directional and have to be removed from the rims and reinstalled. That is the only thing I don't care for, but where I have them done they do no harm. I really like these tires.
#26
Racer
Thread Starter
These part numbers/descriptions came directly to me from Michelin for ordering proper tires...
Fronts...#19713 Michelin Pilot Sport A/S3+ 245/35ZR19 ZP ASY M+S,
All Season Tires
Rears....#05262 Michelin Pilot Sport A/S3+ 285/30ZR20 ZP ASY M+S
All Season Tires
Fronts...#19713 Michelin Pilot Sport A/S3+ 245/35ZR19 ZP ASY M+S,
All Season Tires
Rears....#05262 Michelin Pilot Sport A/S3+ 285/30ZR20 ZP ASY M+S
All Season Tires
#27
Pro
Yep. They had them on their display at the Museum Anniversary.
#28
Pro
#29
Racer
#30
Racer
#31
Race Director
When I ordered my forged wheels I had them shod with AS 3+ in stock sizes months last May. They've been around longer than that.
#32
not in a run flat and by the way found out the answer to rev matching in an auto according to Tadg the chief engineer of the corvette it does
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?
Quote:
Tadge answered:
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.
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?
Quote:
Tadge answered:
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.
#34
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