1 Week and 1250 Km Review
12-11-2014, 09:57 PM
#16
Intermediate
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Thanks for the review, but how did you come up with your gear ratio calculations? Individual ratios for the GT3 are as follows:
1st 3.75
2nd 2.38
3rd 1.72
4th 1.34
5th 1.11
6th .96
7th .84
Final drive 3.97
Overall gear ratios would therefore be:
1st 14.88
2nd 9.45
3rd 6.83
4th 5.32
5th 4.40
You don't show overall calculations for gears 1-3 for the GT3 in your chart but gearing in those gears is shorter than every car listed except the 458. The calculations you do show for gears 4-5 are incorrect, and using the correct numbers the GT3 is shorter geared in 4th and 5th than all cars except, again, the 458.
The only way it would be possible to shorten the ratios further, and keep proper spacing throughout the speed range, would be to reduce top speed significantly. Admittedly this might be useful for US drivers but we have to remember this is a German car, designed for an environment where people take advantage of the upper speed ranges.
1st 3.75
2nd 2.38
3rd 1.72
4th 1.34
5th 1.11
6th .96
7th .84
Final drive 3.97
Overall gear ratios would therefore be:
1st 14.88
2nd 9.45
3rd 6.83
4th 5.32
5th 4.40
You don't show overall calculations for gears 1-3 for the GT3 in your chart but gearing in those gears is shorter than every car listed except the 458. The calculations you do show for gears 4-5 are incorrect, and using the correct numbers the GT3 is shorter geared in 4th and 5th than all cars except, again, the 458.
The only way it would be possible to shorten the ratios further, and keep proper spacing throughout the speed range, would be to reduce top speed significantly. Admittedly this might be useful for US drivers but we have to remember this is a German car, designed for an environment where people take advantage of the upper speed ranges.
12-11-2014, 10:06 PM
#17
Race Director
I engage the PSE button every time I start the car. I'm perfectly happy with the way the car sounds in that mode. The only reason I blocked the vacuum lines was because I thought it would keep me from having to press the button every time. What I discovered is that the system is more sophisticated than just a switch that opens and closes the flapper valves. As soon as I bypassed the computer control of the PSE by blocking vacuum I noticed more noise but also less torque. My conclusion is that even with the PSE button engaged, there is still some modulation of back pressure by the ECU.
Porsche advertises that the sport exhaust is specifically designed to provide a bump in torque. By disconnecting that system part of what the engineers designed into the engine's performance is lost.
More than you asked for, I know....
12-11-2014, 11:32 PM
#19
Race Director
Jon, I think that's why doing it in a garage where there is more resonance may help. There have been a few reports of sticking flapper vales so I suppose it's remotely possible that's why you can't hear a difference.....
12-12-2014, 05:58 AM
#21
Race Director
Great impressions and write-up. My only personal impression/difference is that I do not find the gear ratios to be too tall. I think they are about right for this car. The 991 C2S loaner I had certainly felt like they were way too long and not to my liking. The GT3 revs up pretty quickly which, for me, eliminates the feeling that they are too tall. But an interesting observation though
12-12-2014, 06:36 AM
#22
Three Wheelin'
The short gearing is all for the track. It's perfect for twisties, I just wish there was an overdrive 8th gear for freeway / fuel reduction or a 7th that was a bit longer out.
12-12-2014, 06:53 AM
#23
Rennlist Member
The easiest way to tell the difference is to sit at idle, especially in a garage and engage and disengage the PSE button. Or press the button while just cruising along with the window open at lower rpm. You should hear a difference in both volume and tone. If the button isn't pressed the computer will determine when to open the flaps based on rpm and throttle position.
I engage the PSE button every time I start the car. I'm perfectly happy with the way the car sounds in that mode. The only reason I blocked the vacuum lines was because I thought it would keep me from having to press the button every time. What I discovered is that the system is more sophisticated than just a switch that opens and closes the flapper valves. As soon as I bypassed the computer control of the PSE by blocking vacuum I noticed more noise but also less torque. My conclusion is that even with the PSE button engaged, there is still some modulation of back pressure by the ECU.
Porsche advertises that the sport exhaust is specifically designed to provide a bump in torque. By disconnecting that system part of what the engineers designed into the engine's performance is lost.
More than you asked for, I know....
I engage the PSE button every time I start the car. I'm perfectly happy with the way the car sounds in that mode. The only reason I blocked the vacuum lines was because I thought it would keep me from having to press the button every time. What I discovered is that the system is more sophisticated than just a switch that opens and closes the flapper valves. As soon as I bypassed the computer control of the PSE by blocking vacuum I noticed more noise but also less torque. My conclusion is that even with the PSE button engaged, there is still some modulation of back pressure by the ECU.
Porsche advertises that the sport exhaust is specifically designed to provide a bump in torque. By disconnecting that system part of what the engineers designed into the engine's performance is lost.
More than you asked for, I know....
12-12-2014, 12:08 PM
#24
RL Community Team
Rennlist Member
Rennlist Member
I know someone did a hack for this for the 991 911 to make the PSE "remember" the last setting it was at before the car was shut down. I think they did it by piggybacking on the wiring setup for engine auto shutoff button, which the dealer can program (but which apparently they cannot do for the PSE).
12-12-2014, 01:58 PM
#25
Race Director
There might be, Mark, but I'm guessing it would be more complicated than just rewiring the switch itself since the system reverts to default off mode every time the ignition is turned off even though there has been no change in the switch position. A shame. Anyway, I wouldn't know how to go about doing it.