What is that flintstone house? I passed it on my way back from the dealer.

I just retested across the Golden Gate Bridge and up the hill a bit...mpg was looking better. I left start/stop on and my 991 did a lot of sailing. Unfortunately, to me, PSE and start/stop mix like oil and water. The engine is so noticeable when it is on that when it cuts out it is startling. I just don't see myself using it.

Is it confirmed that sailing is disabled when start/stop is turned off?

 

You are right, I should of clarified. From my understanding on my CTT, the start/stop will not work if it is really hot outside and the A/C is working really hard to cool the car. IF the A/C is just maintaining while its 70F outside than it should not affect the start/stop feature.

I think that the coast feature only works when start/stop is on. Or if you are only in auto mode not manual. Not sure, but I remember seeing that you can turn the function off somehow.

Overall the OP is mentioning how great the sound is with PSE and liking the car better in sport mode. This car should be enjoyed to the max, and concern over mpg should be saved for less enjoyable cars.

 

[quote=DS997c2s;3462260]My computer consistently reports 18.1 mpg with 30% sport mode driving. I drive 20 miles on 280 and then 7 miles on inner roads.

I get 24.5 instantaneous on highway, but only when I want the car to.

ChuckJ gets 22 in town! wow - is DFI more efficient?

I think you guys will get much better after the break-in; I have 25K miles on mine. Sport and plus map everything differently- gas and spark. Porsche doesn’t get graded by the EPA on non-normal modes so they can set it up for sport and track. Sport and sport plus are great, but unless I’m on appropriate roads, I get bored holding 4 or 5K RPM on a straight road. In normal mode I get 28-30 on the highway so I’m confident we’ll get 30-32 straight and level in normal mode after they get broken in.

ChuckJ
PS: The DFI in the 991 has an improved injector that is supposed to improve efficiency.

 

Is it confirmed that sailing is disabled when start/stop is turned off?[/quote]
Yes.

ChuckJ

 

The start / stop button turns on and off both start stop and sailing. With the switch on the Service Information Tech Manual says:
The Auto Start Stop function is not available in the following situations:
Wen Sport mode is activated
When PSM is switched off
During maneuvering
When AC Max mode is activated
When the windshield defrost function is active
At elevations above approximately 9850 feet
After engaging a gear without pressing the clutch pedal when the engine is automatically stopped

It has limited functionality in the following situations:
If the air conditioning or passenger compartment heating is operated a a high setting or the defrost function is running for long periods of time
If the charge state of the battery is low
On uphill or downhill gradients
When the vehicle-internal test processes are taking place, for example automatic engine diagnosis
In the case of excessively low exterior or battery temperature

BTW Automatic engine restart is possible if one of the above states occurs after the engine has been switched off automatically.

ChuckJ

 

It always starts low and averages up

 

The official mileage reports on the window sticker and in advertisements about the economy of the car follow a rigid, exact procedure that is the same for all cars. It goes years without revisions and is rarely changed.

The procedure for city and for highway driving are not likely to be duplicated by the average driver. The car companies depend on this procedure remaining constant and they learn to "game the system." This is not necessarily bad since they are trying to adjust to the laws which ARE constantly changing. If you notice the disclaimer it states that the figures are for comparison purposes and may not reflect your actual figures.

Corvettes and Camaros used a "skip-shift" procedure that was very annoying, but it got them higher mileage ratings on their manually shifted cars.

The EPA cycle does not include hills like San Francisco has or rush hour situations that involve a lot of start/stop, full throttle darts. It also tests the cars in standard, rather than enhanced throttle settings. The cars are fully warmed up, broken in and driven over a strict, always-the-same course. This is what the car is tuned for, to get the best under these circumstances. It is designed to prevent fines and gas guzzling taxes.

Interestingly enough, it is also possible to get better mileage than that stated on the window sticker, but if the car has the fun factor of a Porsche, it is not likely.

 

Attached is my average from earlier today. Sport mode the entire time, all city driving, fastest speed 50mph, kept under 5k rpms, used paddles 30% of the time. The car has about 230 miles on the clock so far.

 

Chuck I believe in Dubai they use the European system of octane rating, meaning the 98 isn't 98 R+M/2. 98 is equivlent to 93 R+M/2, I have a feeling you knew this already.

Dave

 

Here is another " statistic" ... Seems that keeping the revs below 3,000 prolongs the live of the engine substantially... Don't know more than that but it certainly has to do with the piston speed up and down that cylinder.

 

Thanks for all the info, everyone. Is has been helpful.

I turned the car back into Dr. Jekyll with a sleeping baby in the back (I love how this car can transform!) and took a calm freeway drive to the grandparent's house. With start/stop/sailing turned on and no sport modes active I got around 24 mpg. I am satisfied that there is not a hole in my gas tank.

Dropped off the boy, turned on sport mode and manual/paddle shifting and drove it for a few miles in a manner suiting this fine sports car. 9 mpg.

Arthur

 

It’s fantastic, you have two cars in one!!!
ChuckJ

 

Dave:
No, I forgot that they used that system. Thanks for reminding me.

ChuckJ

 

Arthur:
Was you recient trip around the hills of SF or on straight and level highways?

ChuckJ

 

I am right in the middle of SF. My highway driving still has quite a few hills, and my city driving is all hills. Hills and stops.