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Had some time a couple of weeks ago and curiosity got the best of me so we threw my 997.2 on the trusty NASA certified Dynojet that we have used for literally hundreds of pulls in the past. My car is a stock 997.2GT3 with the exception of of 997.2GT3RS 3.89 R&P along with the RS 6th. I also have Soul valved side muffler bypass pipes and an OEM 991GT3 Titanium center muffler. Gas is 91 octane pump fuel. OAT was about 65ºF. After fully warmed up, the car spun the rollers at a very respectable 404whp / 303wtq with sport mode "ON". The curve is very nice as can be seen below.
Just prior to this run, we did a pull with the sport mode "OFF" (yellow/blue). It was very interesting to see that the curve on the "sport mode OFF" run has a significant increase in power (15whp peak) and a corresponding increase in torque of (30wtq peak) up to about 3300 rpm. From 3300 to 4400 the opposite was true as the sport mode "ON" made more power. From 4400 on it was a carbon copy. The difference below 3300 is simply a difference in the ECU mapping between the sport mode ON / OFF operation since the exhaust valves are closed in both cases. The difference above 3300 is likely a combination of the difference in ECU mapping and likely the exhaust valves opening earlier in sport mode ON (about 3500) vs. OFF (about 4300). With that said, it definitely pays benefit to run with sport mode "ON" to maximize the power in the 3300-4400 midrange. It definitely makes the curve smoother in the low to mid rpm range. It would be interesting to do a pull with the valves locked open for the whole pull. We will likely of that next time we get another chance to put the car on the rollers.
For kicks, I overlayed the graph of my 7.2GT3 with that of the 4.0L turbo Mezger that is in my 996 race car. Both were done on the same exact dyno. It's a bit of a humorous comparison in output even with the race motor on a mid power setting.
Cheers....
Last edited by powdrhound; 03-26-2024 at 01:39 PM.
nice power on the 3
your 4 liter race motor is strapped with two turbos
I read the original post in the middle of the night when I had to let the dog out and kept scratching my head at how 800+hp was a mild reliable configuration on an NA motor 😂
Wow...that is really great power to the wheels for your naturally aspirated engine, and thanks for the interesting information about Sport Mode being ON versus OFF. I'm pretty sure the one and only Dragy 60-130 mph run I've ever made with my 3RS is with Sport Mode OFF so of course now I'm eager to try again with it ON. The last graph was particularly entertaining, but also really cool to see how great the power curve really is on your race motor. That's getting down to business!
Wow...that is really great power to the wheels for your naturally aspirated engine, and thanks for the interesting information about Sport Mode being ON versus OFF. I'm pretty sure the one and only Dragy 60-130 mph run I've ever made with my 3RS is with Sport Mode OFF so of course now I'm eager to try again with it ON. The last graph was particularly entertaining, but also really cool to see how great the power curve really is on your race motor. That's getting down to business!
What this basically tells us is that the factory tune is far from optimal and there is a lot of optimization to be had if one had access to control the variocam and other parameters with something like a Motec ECU like we use on my 4.0. Naturally Porsche has emissions and other constraints to deal with so it's understandable why the factory tune is what it is. With that said, you definitely get a smoother curve and more mid range power when using sport mode ON, at least when using the factory exhaust valves as designed, no doubt about it.
Nice! Good seeing these dyno’d still. I just dyno’d my 997.1gt3 at 75k miles.
Also have valved side muffler delete and oem center.
Hit 387whp at Ed Pink’s dynojet
and my buddy’s 7.1 with a 4.0 custom build came along
@powdrhound Related question, but do you recall what you needed to do in order to make your 997.1 GT3 happy on the dyno? Was it as simple as disabling TC/SC or was there more to the effort? My 997.1 GT2 absolutely refused to be dyno'd a couple of weeks ago, but we were unable to fully defeat SC (only TC). Any data points might be helpful as it remains a bit mysterious why the car wouldn't run properly on a RWD or AWD dyno. Thanks!
@powdrhound Related question, but do you recall what you needed to do in order to make your 997.1 GT3 happy on the dyno? Was it as simple as disabling TC/SC or was there more to the effort? My 997.1 GT2 absolutely refused to be dyno'd a couple of weeks ago, but we were unable to fully defeat SC (only TC). Any data points might be helpful as it remains a bit mysterious why the car wouldn't run properly on a RWD or AWD dyno. Thanks!
Car is a 7.2. We turned off the nannys with the switch on the dash. Nothing more.
03-26-2024, 03:35 AM
997.2GT3 Dyno results
