Hello everyone.
I've been researching some of the mechanical aspects of the C8 Z06 and In my opinion, the gearbox leave quite a bit to be desired. I know that most people do not care or won't have a problem with the Z06 as it is a wonderful car to drive. I have also put a deposit down just yesterday to get one hopefully before the end of this year, all thanks to @Mr.Corvette (Scott). But I still have to point this out as a bit of a let down.
Before I state my opinion, I will say that perhaps the reason the gearbox is the way it is, might be down to a lot of things that may or may not be directly related to performance. Things such as desired fuel economy, mechanical stress and durability, emission targets, weight targets, packaging constraints, cost, etc. Nevertheless, the end result in this case and in my opinion only, is either reduced performance or a diminished driving experience.
To cut it short (Hehe), I think the Z06 gears are way too long. With the Z07 high downforce package, your top speed is limited to around 188 mph which is more than adequate, but you reach that speed in 5th gear! In a car with a gearbox that has 8 gears!
Having a tall final drive ratio or top gear or both, will result in reduced RPM at highway cruising speeds which makes the car quieter and increases fuel economy, both great things. However, in a car with 8 gears, this is less of a problem versus let's say, a manual 6 speed transmission.
For example, The ZF 8HP gearbox in a BMW G82 M4 CS that I'm also getting, hit's the same exact top speed but it does so in 7th gear. It's not a DCT, it's a torque convertor unit but the shifts are very fast and very smooth. The gear ratios are much shorter even though the torque output of the S58 engine dominates the LT6 across the RPM range, achieving its maximum torque of 480 lb.ft at 2650 RPM and carrying it to 6000 RPM. The gears are so short that you need to be in third gear to hit 60 mph. That might sound a bit absurd for a car with so much power, but the sensation of going through the gears so quickly, without going so fast as to become a public nuisance and a safety hazard, is immaculate. I think they should have done something similar with the Z06 or even the base corvette.
The 8th gear is so long in the Z06 (0.33:1 ratio) that you'll be ticking at just 1600 RPM when going 70 mph. Very little torque is available at those engine speeds, around 150 lb.ft or less, definitely not suitable for highway driving if you need to overtake someone without having to shift down a few times while driving in manual mode. Even the 7th gear is exceptionally long. At 0.40:1 ratio, you'd be around 1900 RPM doing 70 mph. See the problem here?
I don't know why GM chose these ratios. I really hope, perhaps in the future, they give you an option of shortening the final drive or ring and pinion ratio to make this great car, even better. Seems like a big missed opportunity.
I've been researching some of the mechanical aspects of the C8 Z06 and In my opinion, the gearbox leave quite a bit to be desired. I know that most people do not care or won't have a problem with the Z06 as it is a wonderful car to drive. I have also put a deposit down just yesterday to get one hopefully before the end of this year, all thanks to @Mr.Corvette (Scott). But I still have to point this out as a bit of a let down.
Before I state my opinion, I will say that perhaps the reason the gearbox is the way it is, might be down to a lot of things that may or may not be directly related to performance. Things such as desired fuel economy, mechanical stress and durability, emission targets, weight targets, packaging constraints, cost, etc. Nevertheless, the end result in this case and in my opinion only, is either reduced performance or a diminished driving experience.
To cut it short (Hehe), I think the Z06 gears are way too long. With the Z07 high downforce package, your top speed is limited to around 188 mph which is more than adequate, but you reach that speed in 5th gear! In a car with a gearbox that has 8 gears!
Having a tall final drive ratio or top gear or both, will result in reduced RPM at highway cruising speeds which makes the car quieter and increases fuel economy, both great things. However, in a car with 8 gears, this is less of a problem versus let's say, a manual 6 speed transmission.
For example, The ZF 8HP gearbox in a BMW G82 M4 CS that I'm also getting, hit's the same exact top speed but it does so in 7th gear. It's not a DCT, it's a torque convertor unit but the shifts are very fast and very smooth. The gear ratios are much shorter even though the torque output of the S58 engine dominates the LT6 across the RPM range, achieving its maximum torque of 480 lb.ft at 2650 RPM and carrying it to 6000 RPM. The gears are so short that you need to be in third gear to hit 60 mph. That might sound a bit absurd for a car with so much power, but the sensation of going through the gears so quickly, without going so fast as to become a public nuisance and a safety hazard, is immaculate. I think they should have done something similar with the Z06 or even the base corvette.
The 8th gear is so long in the Z06 (0.33:1 ratio) that you'll be ticking at just 1600 RPM when going 70 mph. Very little torque is available at those engine speeds, around 150 lb.ft or less, definitely not suitable for highway driving if you need to overtake someone without having to shift down a few times while driving in manual mode. Even the 7th gear is exceptionally long. At 0.40:1 ratio, you'd be around 1900 RPM doing 70 mph. See the problem here?
I don't know why GM chose these ratios. I really hope, perhaps in the future, they give you an option of shortening the final drive or ring and pinion ratio to make this great car, even better. Seems like a big missed opportunity.
