I am reposting a post I made on a different car forum to share information and ideas.
Several guys were reporting more boost in sport + mode than sport mode in their 991.2s. I was intrigued with the topic so this morning I went out and tested the theory. Frankly, I was shocked by the results and the implications and I can confirm what others have observed.
For reference, I have a C4 base engine with 7MT, SC and PSE. I did 7 runs total (2 in each mode plus another one in sport + up a hill). Here are the results:
Run 1 and 2: Normal Mode: Max boost was 10 psi on both runs.
Run 3 and 4: Sport mode: Max boost was also 10 psi on both runs.
Run 5 and 6: Sport + mode: Max boost was 14 psi on both runs. (I thought that the max boost on the base engine was limited to 13 psi but I repeated this again up a hill (run 7) on my way home and got the same result of 14 psi). I also achieved 14 psi in second gear.
Each run (1 - 6) was started from 5 mph with WOT in first gear on a flat road . PSE engaged (if that matters at all). Ambient temp was 22 degrees at about 200' above sea level.
So taking ace37's calculations on boost increase to HP gain (13.8 HP per PSI of boost), my car is making 55 more HP in sport + than sport/normal. That seems like a lot if his thumb rule is correct.
So what does the data mean? I think we all agree that increasing boost on the same displacement engine under the same conditions yields more HP right? We also agree that sport + (with SC package) is an option on the car and is not standard.
So when Porsche claims 370 hp, that must mean for the base car with no options correct? So how much HP is my car really making in each mode?
P.S....and like a dumba$$, on run 1, I was so focused on watching the boost gauge that I bounced the engine off the rev limiter. LOL. Oops. Dang this car is fast.
That is interesting.
I assume the hp rating is the maximum power (according to Porsche) that the engine makes (however they measure it). It should not mean that the car is making more power in sport plus mode or that one needs
sport chrono
for max boost to get the full 370 hp.
I suspect the boost numbers are bullcrap. I have seen about 12-14 psi of boost when I floor the throttle in second but never the claimed max of 16.
Perhaps timed acceleration runs in normal, sport and sport plus mode are in order?
When PAG takes a car to the Ring for a speed run, its outfitted with all the performance options, so if they took a S out, it would be with PDDC, SPASM, RAS, etc. Nothing would be missing.
You do know that the sport, sport + stuff is just a software gimmick, limiting or not limiting the engine's ability.
When they build an engine, according to
PCA reports
of people at the factory, the engines they pull from the line for testing MUST make the advertised HP. Otherwise its probably an advertising issue. OTH, it can be OVER by 5%. If its more than 5%, then its pulled to see what went wrong. So if the car is advertised at 370. Then it makes 370. sport + means nothing AFAIK. OTH, you could have got a good one, making 388.
"... actual HP is compared to its advertised HP. To pass final inspection, the engine has to develop, at a minimum, 100% of what its advertised HP rating is. Also, the engine cannot produce more than 5% over that same advertised rating."
Don't know if this answers your question but I
highly
doubt sport + is
anything
but a gimmick but is the full power.
Do you have SC and were you in sport + mode? Those numbers are similar to what guys are getting in sport mode only. They get up to 16psi in sport +.
I disagree with your characterization of driving modes as a gimmick. They aren't. They help you tell the car your intent, which affects how it operates.
The most obvious change is with the PDK. Normal, Sport, and Sport+ modes have different shift points and favor different RPM ranges. Sport+ also does faster (and more abrupt) PDK gear changes. Furthermore, Sport+ works hard to keep the turbos spun up, even at very low throttles, to minimize turbo lag. I've observed this myself in my 991.2 C2: just cruising on the freeway with the PDK in manual, if I switch from Sport to Sport+ the boost readout goes from 0 to 1. Clearly no boost is needed then; it's just keeping the turbo spinning in case I need it.
I've driven other cars with "sport" modes that seemed more like gimmicks. But these modes have real utility and do meaningful things in this case. Well, except for those slightly silly exhaust pops and burbles...
There is a Porsche 991.2 technical document floating around that provides more details on how Sport+ affects the turbos, among other things. It also suggests PSE increases engine power, which I found surprising.
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I drive in sport mode all the time. Never use sport plus. Suspension is too harsh for me in sport plus. For street driving, not sure about the usefulness of sport plus.
Re: Sport & Sport+ have different boosta
Thanks for the Princess Bride clip; it made me laugh!
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