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Do the manual and pdk sound different from 8k to 9k. Pdk seems to have more of that ("those last 500 rpm" noise in the 991.1 gt3). Gearing is also shorter in the pdk version.
I bet the difference is just the microphone/ placement. All the exhaust part numbers, etc will be the same.
Added the 991.1 GT3, which is better than either at the very low end. I suspect they are electronically protecting the newer engine from lugging- all dynos started below 2k rpm.
Surprisingly according to this the 4.0s don't have big gains in the mid-range. They have clearly worked hard tune them for top end power, as stroking would normally increase mid-range disproportionately. RS 4.0 not looking so hot, 991.2 looking very strong. I wonder how much is engine to engine variation, however...
Wow, doesn't seem that the RS really has much on the .1 GT3. IIRC, RS is only about 25 pounds lighter, so lap time gain must be coming from aero, gripper tires, and wider track. Put the new N1 tires on the .1 GT3 and it may be about as fast as the RS on many tracks.
Wow, doesn't seem that the RS really has much on the .1 GT3. IIRC, RS is only about 25 pounds lighter, so lap time gain must be coming from aero, gripper tires, and wider track. Put the new N1 tires on the .1 GT3 and it may be about as fast as the RS on many tracks.
I'm growing suspicious that this particular .1 RS was off a step. It didn't dyno at 500 and it was rather slow around the 'ring. Other straight line acceleration numbers suggest the gap should be bigger than these curves show.
As noted previously the 997 RS 4.0 still has more mid-range torque than any of them, though it finally has noticeably less area under the top of the power curve than the 9A1.5. I'll also repeat: I'm 98% sure Porsche is intentionally trying to limit mid-range torque in all of these engines to improve the "feel" of the top end rush.
Still- damn that was a good motor, and in a significantly lighter car...
Thanks for the graph, quite interesting to see the differences. Not bad going for the old girl really still despite being a much older design!
As noted previously the 997 RS 4.0 still has more mid-range torque than any of them, though it finally has noticeably less area under the top of the power curve than the 9A1.5. I'll also repeat: I'm 98% sure Porsche is intentionally trying to limit mid-range torque in all of these engines to improve the "feel" of the top end rush.
Still- damn that was a good motor, and in a significantly lighter car...
Pete, I love the overlays of the graphs, lots of fun work to see the result. How comparable are these, though?
Do you think there is a possibility the curves may shift slightly if all these cars are brought under one roof and tested on the same day and conditions?
Do you think there is a possibility the curves may shift slightly if all these cars are brought under one roof and tested on the same day and conditions?
And you gotta make sure there's a bit of a turn in the steering wheel so the ECU doesn't go into emissions testing mode.
And you gotta make sure there's a bit of a turn in the steering wheel so the ECU doesn't go into emissions testing mode.
In all honesty though, I would love to see error bars on these graphs. I have run cars on a dyno 5 minutes apart and seen 2-5% difference. Even the guy who sets up the machine and fans can make a difference.
Edit: we need all these cars under one roof with Dundon. I trust these guys, we will have the answer.
Pete, I love the overlays of the graphs, lots of fun work to see the result. How comparable are these, though?
Do you think there is a possibility the curves may shift slightly if all these cars are brought under one roof and tested on the same day and conditions?
I believe most of these were on the same high quality calibrated dyno, the weather was comparable and they were all corrected for temperature and pressure variation- they should be fairly close.
That said car to car variation and other errors will still be issues, and the article noted problems dynoing the 991.1 GT3... Even if it's entirely accurate keep in mind that +/- 2% is 10 hp at this level, so it's fairly likely that a strong version of the weakest car would be nearly on top of a weak version of the strongest car. Thus if you got 4 different cars I guarantee the results would change slightly, despite which this can still teach us quite a lot...
I believe most of these were on the same calibrated dyno, the weather was comparable and they were all corrected for temperature and pressure variation- they should be fairly close.
That said car to car variation and other errors will still be issues, and the article noted problems dynoing the 991.1 GT3... Even if it's entirely accurate keep in mind that +/- 2% is 10 hp at this level, so it's fairly likely that a strong version of the weakest car would be nearly on top of a weak version of the strongest car. Thus if you got 4 different cars I guarantee the results would change slightly, despite which this can still teach us quite a lot...
Thanks! Either way, there is no question that .2 GT3 engine dominates its predecessors.
06-09-2017, 09:14 PM
