Mech33

So Porsche says that the V8 4.0 turbo in the Turbo model goes into cylinder deactivation any time less than 200 and something Newton-meters of torque output is requested from the motor (less than half throttle, essentially). And in cylinder deactivation mode, half of the cylinders are active, making it a 4-cylinder motor in that mode.

So, most of the time the Turbo is being driven around town, it’s actually a 4-cylinder. Had anybody noticed it sounding substantially different as a result?

I wonder if it disables cylinder deactivation in the Sport modes.

JCWLS3

I remember reading about cylinder deactivation on the V8 as well. Assuming the technology is in fact in place on our Turbo, it's totally seamless. We can't sense a thing.

That a far cry from the Cadillac V8-6-4 of the early 1980s. Somebody had to be a pioneer, but man, what a disaster that engine was...

https://en.wikipedia.org/wiki/Cadill...368_and_V8-6-4

SilverSteel

I remember.

scott40

Well you can’t tell from a fuel consumption standpoint. Around town mpg is poor...but it sounds great with PSE!

Mech33

Im amazed the car only gets 15-18 mpg in 4-banger mode! What would V8 mode be like??

MaxLTV

Can you link to the source (not doubting, just curious to read more)? I remember reading this back when Panamera was launched with the same engine, but could not see it mentioned anywhere regarding the Cayenne. Sometimes at idle it does sound like the firing of cylinders is too widely spaced for the revs but not exactly like a typical 4-cylinder, but I attributed it to exhaust configuration rather than cylinder deactivation.

Mech33

Hmm good point. This is only really mentioned in older articles from the 4.0T engine's debut, such as here: https://www.caranddriver.com/news/a1...win-turbo-v-8/

Perhaps Porsche didn't enable cylinder deactivation on the Cayenne Turbo? The abysmal fuel economy would certainly suggest that, perhaps. Now if we could just disable Start/Stop permanently, too...

MaxLTV

That could be the case because Panamera gets much better fuel economy with this same engine. By the way, highway economy is pretty good - slightly better than 911 Turbo S in Sport mode but worse than 911 Turbo S in Normal mode. It's the city consumption that is not good. I think that's where mild hybrid approach would help - stop signs, parking etc.

PMPC19887

I am curious about this as well. I was recently shopping for a Cayenne Turbo and our sales advisor mentioned this. He showed us some marketing materials for the Cayenne Coupé Turbo that highlighted the cylinder deactivation and rpm that triggers the car back into 8 cylinder mode. I thought it was odd, as most people buying a turbo would always want instant access to the extra power they are paying for? There didn’t appear to be a way to turn it off, maybe sport mode? Interested if anyone who does a lot of city driving in the Turbo has noticed this.

JCWLS3

I will say this: Whether the Turbo has cylinder deactivation or not, fuel economy is about what I expected for a 5000-pound, 550-horsepower AWD SUV. We average between 14 and 16 mpg on a given tank. This is calculated not by the notoriously optimistic onboard computer, but rather the old-fashioned way at the pump: miles driven divided by gallons pumped. We've had a few outliers in the 13s and 17s. Generally it hovers between 15 and 16.

We do have heavy right feet, which is compensated somewhat by the fact that my wife's commute is 70 miles of mostly highway driving. That is complicated, however, by the fact that highway driving could mean breezing along at 90, or stuck in bumper-to-bumper for two hours.

Overall, we're not displeased by the mileage. Pretty impressive all things considered.

MaxLTV

Power is always instant. In fact, sport mode is less necessary than in even in 911, probably because there is less turbo lag in the Cayenne at very low revs. Much better than previous gen Turbo that was a complete lag-fest from low RPMs.

DAVfoto

Mixed driving?

I know mine doesn't have the HP but my GTS averages nearly 22 highway when I'm driving at about 75-80. Around town it's different as I get about 15 ish. And yea I do the same method, miles driven divided by how much gas was pumped. Then reset ODO after every fill up.

pokingaround

For another data point: in my 2018 Panamera Turbo in Normal mode with PSE active I get 23 MPG+ on highways cruising at 75-80. Actually extremely impressed by the mileage all things considered. Even around town in Sport with a heavy-ish foot I get in the 17-18 range. I only dip into the 15 range when I'm really being aggressive in Sport+. Seems like cylinder deactivation is definitely a thing in the Panamera. Frankly I can't tell the difference in sound or performance.

George718

Total disaster to say the least!

turbo power

I am not surprised if that is the case- Normal mode does seem quite "laid back" but the Sport Chrono is right there for instant gratification. I don't know my mileage but the large gas tank certainly helps avoid frequent visits to the gas station.

In addition to all the other gadgetry, perhaps the V4/ V8 mode helps the multiple personalities: normal day to day city driving plus GT cruiser plus killer Sport Plus mode to out-accelerate pretty much anything out there.