Back in April of this year, GM Authority presented a video showing how the engine in the 2021 Cadillac CT5-V high-performance luxury sedan makes a (really pleasant) popping sound when the vehicle’s GM Hydra-Matic 10-speed automatic gearbox shifts from one gear to the next under hard acceleration.
As we mentioned at the time, this happens only when the throttle is either wide open or close to wide open. If the transmission is allowed to choose when to change gear in that situation, it will do so at maximum revs. Therefore, it’s unlikely that the driver will hear more than a couple of pops before having to back off (due to the speed being gained).
However, the driver can also force the popping sound by manually short shifting while remaining on full throttle. Anyone who really likes the pops will almost certainly take advantage of this.
So that’s all just dandy, but what causes the pops? Cadillac spokesperson Stefan Cross recently explained to GM Authority that they are achieved by cutting the fuel supply very briefly as the next gear is being selected. The process of reacting to information that a shift is about to take place, shutting off the gas and then allowing it to flow again once the shift has been completed is almost too fast for the human mind to contemplate, but it’s an easy job for a modern electronics system.
As pleasant as the pops may be, they are not the primary reason for the shut-off. The more useful effect involves cutting torque while the shift is taking place. The on-off-on sequence of energy going through the drivetrain is therefore less harsh than it otherwise might be, and greatly reduces the chance of failure.
The energy involved is considerable. Although the “regular” Cadillac CT5-V is nowhere near as powerful as the upcoming 2022 Cadillac CT5-V Blackwing, its twin turbocharged 3.0L V6 LGY gasoline engine still produces a very healthy 360 horsepower and – more importantly in this context – 405 pound-feet of torque (actually slightly less than that at peak revs, but still a lot). Removing as much strain as possible from the drivetrain is a wise move on Cadillac’s part.
The Cadillac CT5-V is built at the GM Lansing Grand River plant in Michigan, and is available with rear-wheel-drive or all-wheel-drive. It’s priced to start at $48,990 in the U.S., including $1,195 delivery charge.