dflowerz

Guess I wasn't clear. I was trying to say that I can check max boost on my car by pushing the sport response button and flooring it. It's kind of the all hell breaks loose button. Porsche says with sport response the turbos are allowed to overboost. Not sure exactly what that translates too in actual boost pressure. Will try and find out next time. Flooring it at reasonable revs in sport+ would probably give a similar result but would not, I guess, bring in the mythical overboost. feature. To be honest I don't much care, but would like to help answer the question.

Ski Porsche

There's no overboost function on the 3.0 turbo motors. I've seen 16 psi in my 4S.

Jenner

Sorry to have to correct you but this is wrong. Sport Response puts the car into optimal performance mode. It does not increase it beyond factory spec.

No matter what mode you are in (normal, sport, sport +), no matter what setting the PDK transmission is in (ie manual mode or not) it preps the car for 20 seconds of optimal performance and drops to the lowest available gear for your current speed, puts the car into sport + (if it isn't already) for you instantly all with just 1 button press (instead of multiple and having to manually kick down PDK or press throttle kick down button).

"In SPORT Response mode, the engine and transmission are set to maximum response with timer-control:

Faster build-up of boost pressure
PDK switches to special gearshift map"




As you can see from this chart found in the owners manual Sport Response and Sport + modes are the same exact thing EXCEPT for PDK transmission. This also explains why the 7 speed manual transmission doesn't have Sport Response. The only difference between Sport + and Sport Response on a 7MT is that the driver has to drop to the lowest gear manually. Assuming that happens they are identical.

This "Sport Response" PDK setting may or may not be more "aggressive." From my personal experience on the track @ PEC the only difference between Sport + and Sport Response is that Sport Response goes to and holds the lowest available gear where Sport + won't downshift to the absolute lowest gear until you hit the throttle. In other words Sport Response is primed/ready to go where with Sport + there is a slight delay due to transmission kick down. I own a 7MT but drove a PDK hard @ PEC, so PDK guys let me know if you feel the same.

Sport Response is NOT to be confused with an "overboost button" nor does it have a cool down or lock out timer. You can press sport response over and over again forever for your 20 seconds of optimal performance repeatedly if you wanted. Any magazine article that says there is overboost during Sport Response is 100% wrong. They are confusing it with Sport + mode on the 991.2 which is very different from the Sport + behavior on the 991.1

On the .2 you do NOT get the pops and crackles or different throttle mapping., instead the throttle body is open and the engine acts like an air pump to keep the turbos spooled in a "anti lag" type mode. You can be coasting with 0% throttle and switch into Sport + and watch the boost gauge build up to 2psi of boost (I've seen spikes of 4psi on mine) and you can hear this via the exhaust as well. This is more anti-lag than any "overboost" (I suppose one could argue it is a overboost compared to other turbo engines out there that make 0psi when coasting). I would wager this is where journalists who don't pay attention or understand are getting it mixed up, or it just sounds better in their article for the layman reading it.

Hope this helps clear that up.

subshooter

Wow. Thanks for the detailed reply.

wisky

I am on the original full tank of gas supplied by my dealer . Perhaps they put 87 octane in the car ? I will run this tank dry and fill up wit 93 and report back.

ace37

Among other factors, air temperature and altitude can have a significant impact on the amount of boost your car produces as they change the air density. Lower density -> more boost to get the same total pressure in the engine. I'm at high altitude so I typically see a bit (2-3psi) more boost than the car is supposed to produce at sea level. It's simply compensating for the altitude / lower air density. It provides less of this "extra" boost at lower ambient temperatures as the air density isn't quite as low. (And this is exactly why turbochargers were invented.)

I wouldn't be surprised if our ECU also works the other way and boosts to a bit less than the typical boost pressure when the car is in very dense air.

wisky

At what gear / RPM are you seeing 16PSI?

wisky

I just filled the tank with 93 octane gas. I am still seeing 12, 13 PSI at WOT from 3000 - 6000 RPM . I saw 15psi ONCE at 6000 RPM in 2nd gear at WOT today. I must've went 2nd to 3rd gear WOT 40 times today trying to see a steady 16 PSI. I am driving myself insane over this.

Dewinator

Hmm maybe see if the dealer will let you take a different car out for a test drive? That way you can see another in the same conditions.

wisky

I stopped by my dealer yesterday (Saturday) to express my concerns and ask if they have any 7MT 2S or 4S I could drive. They said they did not, they asked if I could come back during the week when the service manager was there. I did see 15 psi ONCE yesterday, but it should not be a battle to see the max boost pressure for this car, let alone 1 psi under max boost.

Valvefloat991

Your logic and explanation make perfect sense, but I'm in the Denver area with my 991.2 Carrera and have never seen more than the nominal 13 psi boost. Not even when charging hard on Squaw Pass road on the way to Mt. Evans and hitting triple digit speeds. That road peaks at a bit over 11,000 feet.

P-car fan

EXCELLENT description, thank you! That clears up everything regarding all the modes, which I've been a little confused on myself while driving my .2S PDK

Ski Porsche

Wisky--It was 1st gear in the lower and middle rpm. I'll have to look more closely for the rpm range. I live at 5,100'.

Jenner

Had my Targa 4S out yesterday and was able to do some testing for you. I am closer to your location/conditions as I am in southern CT near NYC ~200 ft above sea level temps were between 75-89*

Manual transmission so I don't have sport response but I was in Sport Plus.
2nd gear and 3rd gear easily saw 16psi with several quick spikes to 17psi.
Would see 16psi from 5000-7000rpm.

I need to do more testing but I don't recall seeing above 15psi in Sport mode.

I believe the spikes to 17psi were due to my Fabspeed headers and sport cats.
(EDIT: nope guess 17psi is normal:
https://rennlist.com/forums/991/9858...l#post14116512)

Not sure if this helps but I set my boost gauge to be at the top of the LCD cluster. I believe this is the default location for fuel range and is curved (not a straight line like default boost or oil pressure is lower in the gauge).

So the next question is what mode are you testing your car in?
If you haven't been using Sport Plus then maybe this will solve your issue.

Alec Syme

OP, How many miles do you have on the car?I just bought a new C2S and my dealer told me Porsche limits boost until the car reaches 1200 miles. Not sure by how much, but it's a thought. My car has only 500 miles so far so I'm going a little easy yet. Not pushing the boost at all yet.

Alec