It could be that Sport+ is more aggressive and wants to get you to peak torque sooner, thus the higher boost levels. (yet max torque/hp is the is the same between Sport and Sport+)

 

Possibly. With colder weather, more aggressive boost ramp-up from different settings, the boost can certainly spike to a higher level than the target. Basically, the control system is too slow and overshoots the target.

 

Until someone puts their car on a dyno and does separate runs in normal, sport, sport +, there isn’t much substance to go by here. All the people crying foul because the PCM boost gauge (which is VERY inaccurate - ask GIAC, Champion, etc) doesn’t report max boost consistent with Porsche marketing, ya’all need to calm down. 1. These cars have software artificially controlling max boost, air/fuel ratio, etc and if you don’t like it, buy GIAC’s tune. 2. If you want an accurate boost estimate, install a boost gauge. 3. These cars are not lacking power, at all, regardless of which drive mode you are using, and 4. LOL to the guy in South Korea that wants to detune his GTS...

 

I think this is a logical answer. However, it still changes the T/HP curves in sport + mode.

 

Exactly right My base 991.2 shows peak boost of 11 psi, even though I'm in Colorado and would expect the engine to be making more than the nominal 13 psi in order to compensate for the thin air. I believe that with many modern cars, the boost is not measured directly, but is derived from a mass airflow/rpm calculation, which further muddies the waters.

I'd love to see dyno curves with a sensor-measured boost also indicated.

 

 

The result on a dyno could show nothing because you usually dyno only in the gear closer to 1/1 (generally 4th, 5th gear).

On a Mercedes Cla45AMG (more then 27.5 pounds of boost stock), the engine only provide max boost in 4th gear... for exemple 1st 10 ibs 2nd 15 ibs 3rd 20 ibs etc...

So far the comparison between the modes have been in 1st and second gear .

If your car in conditions (colder climates will probably run less boost) run 10 or 11 pounds of boost is it only in first and second gear? In sport plus do you get 4 pounds of additional boost in 3 , 4th etc...

 

 

I just ran at Willow Springs today with my GTS. Tried different settings prior to going down the main straight.
The sport and sport +settings and the sport button all produced 19 psi per the gauge. I didnt try normal ( which might produce less boost).
This car is a hell of a lot faster than my cayman gts, even with street tires. The pirelli pzeros were not bad ( type N1).
Reasonable wear and I pulled 1.45 g in the corners( and I wasnt really trying as it was the first time out with the car).

 

I've never seen 13 psi, summer or winter (20 degrees). And while you are correct that Colorado fuels are about two octane numbers lower in each grade than fuels at sea level, at 20 degrees, the car is unlikely to be octane limited even with Colorado regular.

 

Great feedback, and would have been very curious to see your boost levels in the Normal mode.

Also great feedback on the Pirelli N1s, which dovetails with what some of the Porsche engineers tell me—they can match Pilot Sport Cup 2s for ultimate grip...for one lap, anyway.

And yes to you and Mike: The new GTS hauls. It's hard to call a $125K car a performance bargain, but that's what it is.

 

I switched on Sport+ today for the first time in my GTS. While I can't say anything about max boost, since I never came close to it, there's no question that the turbochargers behave differently in Normal vs. Sport vs. Sport+.

In Normal I never see more than 1-2 pounds of boost, and if I blink I miss it.
In Sport there's a bit more, but still not much. I don't think I ever saw more than 4 PSI.
In Sport+ I easily hit 7-10 pounds of boost, and it tended to hold at least 1 PSI for a long time after I stopped accelerating. Up to 10 seconds, I'd say, though I didn't really time it.

All of this driving on surface streets, never getting above about 45 MPH. I have a manual transmission car, so PDK wasn't a factor. Given the above, I'd say that Sport Chrono is now a must-have even in manual transmission cars. On a race track the car's going to hold on to boost all the time, but if you're doing something less than that and something more than sitting behind traffic, it's definitely going to be more responsive in Sport+.

 

Is there any consensus about what folks are seeing in boost pressure on the various models? I have not really tried, but on two occasions on the highway today I floored it and noticed 16 psi on the turbo gauge. I was already at highway speeds and just accelerated from there--not a launch. I did it one time in sports and one in sport plus with the same results. Did not hit the "go fast" button. I do have a PDK car and it does have Sports Chrono. My car is a 2017 4S. Was surprised to see 16 psi from having read some of this discussion, but it may be that for a 4S with sports Chrono that is normal and the slightly higher figures for the GTS and lower for base is just part of the tuning Porsche has programmed for each level of vehicle?

 

According to Porsche, the base does 13psi, the S 16psi, and the GTS 18psi max.
Your results can vary

 

I have since taken my 991.2 base Carrera for a track day and used the torque app to record peak boost. The highest figure I saw was 16.4 psi, which when added to the barometric pressure of 12.2 psi, yielded a manifold pressure of 28.6 psi.

At sea level, of course, the baro pressure would be 14.7 psi and if you add the nominal 13.0 psi of boost, you would get a manifold pressure of 27.7, or essentially what I saw. So it looks like Porsche let's the engine develop more boost so that ti can develop sea level power at altitude--more or less--at least at 5000 feet or so.

However, the boost gauge in the PCM only showed 13 psi. Apparently Porsche doesn't allow this maximum reading to vary, to avoid confusion among the geniuses who buy their cars.

By the way, this was on a very warm day. According to the car, via the Torque app, ambient temperature was as high as 102 degrees and the highest intake air temp I saw was 171.

Fuel was standard premium, 91 octane in Colorado, from the nearest gas station. But the engine was making good power based on peak speed on the back straightaway and my lap times. However, the exhaust pipes were showing heavy white deposits, apparently impurities in the oil and fuel that precipitate at extending high temps.