No-lift shifting seems like a simple concept. Instead of lifting off the throttle while shifting a manual transmission, you just keep your right foot planted. But there’s more to it than that, especially with turbocharged engines, as detailed in this video from Engineering Explained.
A handful of production cars have offered no-lift shifting features from the factory, ranging from the Chevrolet Cobalt SS to the current Cadillac CT4-V Blackwing.
In the Cadillac, there’s a twin-turbocharged 3.6-liter V-6, a type of engine where a no-lift shift can be particularly helpful for maintaining boost. However, if the car isn’t set up for it, you also risk damage to the transmission. Keeping your foot on the throttle raises engine speed, putting a lot of extra load on the clutch when its time to re-engage.
One way to maintain boost without allowing the engine and transmission speeds to get out of sync is by retarding the ignition. This allows for increased exhaust pressure to keep the turbo spooled up without spinning the crankshaft faster. A fuel cutoff ensures the engine doesn’t rev past its redline, while the turbo’s waste gate is kept closed to harness the added pressure being generated.
Cadillac’s no-lift shift system also keeps the intake bypass valve closed. This would normally open when off throttle to prevent excess air pressure from building up in the intake and getting pushed back into the turbocharger, a phenomenon known as “turbo surge.”
In the CT4-V Blackwing, both the throttle and bypass valves stay open while no-lift shifting, ensuring there’s plenty of boost ready to go when the clutch re-engages.
The Cadillac CT5-V Blackwing also has no-lift shifting, but that likely produces less benefit with the larger sedan’s supercharged 6.2-liter V-8 because there are no turbos to keep spooled up. But it does mean you can keep your right foot down while running through the cars, which is cool no matter what engine you have.
This article was originally published by Motor Authority, an editorial partner of ClassicCars.com
I was flat shifting back in the 60’s with my 68 Camaro SS Big Block 396CI 375HP factory Camaro ,I bought it when I came back from Vietnam off the showroom floor and when I got out of the Marines in 69 I did a lot of work on the car in the shop I work at,I took if from 12.6 to 11.5
In the Qtr mile,I was quick with my shifting and many people asked me it the Car was automatic
Miss those days had to sell the car because I got married had two daughters and they were diabetic and Insurance didn’t cover much then like today’s delimma
Back in day, simply known as a “power shift.”