Somebody school me on manual 991.2 Sport Chrono settings and boost
05-09-2018, 10:36 PM
#1
Rennlist Member
Thread Starter
Somebody school me on manual 991.2 Sport Chrono settings and boost
All,
I've been noticing something recently while driving my manual Carrera T. In Normal or Sport mode, I rarely see any boost unless I'm at wide open throttle. Maybe 1-3 psi. In Sport + however, I'm getting 1 psi of boost at any throttle position, and it is highly aggressive from there with 10+ psi available at 50% throttle. This is anecdotally confirmed via butt dyno - acceleration is much more immediate in Sport +.
I'm curious if the ECU is somehow keeping the turbos spooled in Sport + (it almost seems like there's a battery assist, as I'll have 1psi boost available at 1000rpm).
The other manual cars I drove prior to the Carrera T didn't have Sport Chrono (at least I don't recall that they did). And the PDK cars which did had significant transmission differences in each mode which overshadowed the turbo/throttle mapping.
I've been doing some hunting in the manual and on the boards, but I've not seen this behavior described elsewhere. Could it be a Carrera T thing?
Thanks for the discussion in advance, really looking forward to hearing everyone's thoughts.
cheers!
I've been noticing something recently while driving my manual Carrera T. In Normal or Sport mode, I rarely see any boost unless I'm at wide open throttle. Maybe 1-3 psi. In Sport + however, I'm getting 1 psi of boost at any throttle position, and it is highly aggressive from there with 10+ psi available at 50% throttle. This is anecdotally confirmed via butt dyno - acceleration is much more immediate in Sport +.
I'm curious if the ECU is somehow keeping the turbos spooled in Sport + (it almost seems like there's a battery assist, as I'll have 1psi boost available at 1000rpm).
The other manual cars I drove prior to the Carrera T didn't have Sport Chrono (at least I don't recall that they did). And the PDK cars which did had significant transmission differences in each mode which overshadowed the turbo/throttle mapping.
I've been doing some hunting in the manual and on the boards, but I've not seen this behavior described elsewhere. Could it be a Carrera T thing?
Thanks for the discussion in advance, really looking forward to hearing everyone's thoughts.
cheers!
05-09-2018, 11:10 PM
#2
Rennlist Member
This is an excerpt from Porsche’s 991.2 techical training document. I believe “sporty” refers to sport or sport+ modes.
In designing the turbocharging, particular importance was placed on the responsiveness of the turbochargers. For this purpose, the turbochargers are “primed” during sporty driving in the part load range. Here, the wastegate valves are closed, the ignition point is retarded and the throttle valve is closed slightly. In this way, the current drive torque remains the same, the air-flow rate through the engine is increased and the boost pressure upstream of the throttle valve rises. During subsequent acceleration with fully depressed accelerator pedal (throttle valve fully open), the required boost pressure and a higher torque are immediately available.
During the load change at full-throttle acceleration, the responsiveness of the turbochargers and therefore of the engine has been improved. When the accelerator is released (vehicle in overrun), the throttle valve is not closed. As a result, the boost pressure is not completely depleted and is available again following renewed actuation of the accelerator pedal for a further acceleration.
In designing the turbocharging, particular importance was placed on the responsiveness of the turbochargers. For this purpose, the turbochargers are “primed” during sporty driving in the part load range. Here, the wastegate valves are closed, the ignition point is retarded and the throttle valve is closed slightly. In this way, the current drive torque remains the same, the air-flow rate through the engine is increased and the boost pressure upstream of the throttle valve rises. During subsequent acceleration with fully depressed accelerator pedal (throttle valve fully open), the required boost pressure and a higher torque are immediately available.
During the load change at full-throttle acceleration, the responsiveness of the turbochargers and therefore of the engine has been improved. When the accelerator is released (vehicle in overrun), the throttle valve is not closed. As a result, the boost pressure is not completely depleted and is available again following renewed actuation of the accelerator pedal for a further acceleration.
05-11-2018, 04:04 PM
#3
Rennlist Member
I remember reading about that feature. I have just a 991.2 4S but I have noticed that it has little to no "turbo lag" when I drive it (which is always in Sport or Sport+). Cool tech imo.
05-11-2018, 09:40 PM
#4
I also only see the maintenance boost (1 psi) in sport plus. It seems to provide a distinct increment in performance versus normal and sport mode. Wish I could have it without the auto rev match though.
05-11-2018, 10:10 PM
#5
Pro
Not just a T thing. I've migrated to using Sports + as my default setting, at least once the engine is warmed up. Like when I hit the interstate ramp on my daily commute. My GTS coupe comes alive, sounds good, is responsive and appropriately firm. A proper sports car.
You can defeat rev matching in Sports + by disabling PSM, though in my car it is a bit of hit or miss, sometimes I have to cycle the button a couple of times, which is annoying .
You can defeat rev matching in Sports + by disabling PSM, though in my car it is a bit of hit or miss, sometimes I have to cycle the button a couple of times, which is annoying .
05-11-2018, 10:25 PM
#6
Rennlist Member
Check out this thread. A lot of good discussion.
https://rennlist.com/forums/991/1041...ent-boost.html
https://rennlist.com/forums/991/1041...ent-boost.html
05-11-2018, 11:14 PM
#7
Rennlist Member
Thread Starter
Check out this thread. A lot of good discussion.
https://rennlist.com/forums/991/1041...ent-boost.html
https://rennlist.com/forums/991/1041...ent-boost.html
Trending Topics
05-12-2018, 11:37 AM
#8
Rennlist Member
The turbo six in my C4S is absolutely fantastic. Power builds in a very linear fashion and the car pulls hard upto 6k rpms with a very satisfying and characteristic flat six sound. Porsche engineers did an amazing job replicating the feel of an NA engine. Very hard to tell it is a turbo except for the sounds of the turbos whistling at 2000 rpms. I thought the 420 hp and all the low end torque would make the car too fast for the street. Not so at all because of the nature of the engine's response. And coupled with a MT it is very easy to manage.
05-12-2018, 06:27 PM
#9
The turbo six in my C4S is absolutely fantastic. Power builds in a very linear fashion and the car pulls hard upto 6k rpms with a very satisfying and characteristic flat six sound. Porsche engineers did an amazing job replicating the feel of an NA engine. Very hard to tell it is a turbo except for the sounds of the turbos whistling at 2000 rpms. I thought the 420 hp and all the low end torque would make the car too fast for the street. Not so at all because of the nature of the engine's response. And coupled with a MT it is very easy to manage.
Another .2 C2S owner
Absolutely love the 7M with this engine.