991.2 GT3 - Manual Gear Ratios and Gear Speeds
03-09-2017, 12:55 PM
#16
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Bummer. And I thought the GT4 gearing was long. Hope there's an alternative r&p that fits or will be made...
Can't use 2 gears on the street. Probably no more than 3 gears on many tracks. Might as well have the PDK if there will be no gearing solution.
Yes, this is MPH. This is the theoretical top speed in each gear based on all required mechanical parameters. Of course the car does not have the power/aero to top out 5th or 6th gear.
Feel free to plug in the following data: 27.2" tire height (305/30/20, 3.091 final drive, 9000 rpm redline, ratios (3.75,2.381,1.72,1.344,1.081,0.881)
1st Gear (mph): 63
2nd Gear (mph): 99
3rd Gear (mph): 137
4th Gear (mph): 175
5th Gear (mph): 218
6th Gear (mph): 267
Can't use 2 gears on the street. Probably no more than 3 gears on many tracks. Might as well have the PDK if there will be no gearing solution.
Yes, this is MPH. This is the theoretical top speed in each gear based on all required mechanical parameters. Of course the car does not have the power/aero to top out 5th or 6th gear.
Feel free to plug in the following data: 27.2" tire height (305/30/20, 3.091 final drive, 9000 rpm redline, ratios (3.75,2.381,1.72,1.344,1.081,0.881)
1st Gear (mph): 63
2nd Gear (mph): 99
3rd Gear (mph): 137
4th Gear (mph): 175
5th Gear (mph): 218
6th Gear (mph): 267
One way to know your numbers are wrong is that the car goes 198 mph at close to 8,250 rpm (power peak) in 6th gear, so theoretical maximum speed in 6th at redline (if wind resistance didn't prevent it) would be 216 mph (not 267)
03-09-2017, 12:57 PM
#17
Race Car
Join Date: Jan 2013
Location: The way to hell is paved by good intentions “Wenn ich Purist höre...entsichere ich meinen Browning” "Myths are fuel for marketing (and nowadays for flippers too,,,)" time to time is not sufficient to be a saint, you must be also an Hero
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if they build without the jurnos obsessions
0-60mph and Ring sub 7.30s
but only for fun
gears should be much shorter
maybe they listen and they finally make a purist but usable car
so far switching only 2nd to 3rd back and forth
BC other wise you ll kill yourself
IS BORING longish gearbox purist only on paper and not usable in real life
that s why so far i buy pdks only (at least has a sense on track)
0-60mph and Ring sub 7.30s
but only for fun
gears should be much shorter
maybe they listen and they finally make a purist but usable car
so far switching only 2nd to 3rd back and forth
BC other wise you ll kill yourself
IS BORING longish gearbox purist only on paper and not usable in real life
that s why so far i buy pdks only (at least has a sense on track)
03-09-2017, 01:29 PM
#18
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Here is an interesting gearing comparison that turbofreeFLAT6 made:
03-09-2017, 01:31 PM
#19
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In particular look how much lower the gearing is for the 911R (and 991.2 GT3) than the GT4 by Looking at the speed in each gear at 7,000 RPM (last 2 rows of the second chart above)...
03-09-2017, 01:34 PM
#20
This came up previously. the R almost certainly has a final drive of 3.89 not 3.09 that must have been a misprint. Porsche are very good at using existing parts, a 3.89 final drive exists and works. A 3.09 does not afaik.
03-09-2017, 01:35 PM
#21
Drifting
Join Date: Aug 2015
Location: Toronto - Exuma - Montego Bay
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@GrantG -Thank you muchly for providing this information.. I was left scratching my head earlier.. Will have an in-depth look and play with the calculator once my day is over... great way to end the day, 
03-09-2017, 01:35 PM
#22
Three Wheelin'
Bummer. And I thought the GT4 gearing was long. Hope there's an alternative r&p that fits or will be made...
Can't use 2 gears on the street. Probably no more than 3 gears on many tracks. Might as well have the PDK if there will be no gearing solution.
Yes, this is MPH. This is the theoretical top speed in each gear based on all required mechanical parameters. Of course the car does not have the power/aero to top out 5th or 6th gear.
Feel free to plug in the following data: 27.2" tire height (305/30/20, 3.091 final drive, 9000 rpm redline, ratios (3.75,2.381,1.72,1.344,1.081,0.881)
1st Gear (mph): 63
2nd Gear (mph): 99
3rd Gear (mph): 137
4th Gear (mph): 175
5th Gear (mph): 218
6th Gear (mph): 267
Can't use 2 gears on the street. Probably no more than 3 gears on many tracks. Might as well have the PDK if there will be no gearing solution.
Yes, this is MPH. This is the theoretical top speed in each gear based on all required mechanical parameters. Of course the car does not have the power/aero to top out 5th or 6th gear.
Feel free to plug in the following data: 27.2" tire height (305/30/20, 3.091 final drive, 9000 rpm redline, ratios (3.75,2.381,1.72,1.344,1.081,0.881)
1st Gear (mph): 63
2nd Gear (mph): 99
3rd Gear (mph): 137
4th Gear (mph): 175
5th Gear (mph): 218
6th Gear (mph): 267
03-09-2017, 01:36 PM
#23
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R&P is 3.89:1 - see turbofreeFLAT6's charts above...
03-09-2017, 01:41 PM
#24
Three Wheelin'
1st gear - 50 mph
2nd gear - 78 mph
3rd gear - 109 mph
4th gear - 140 mph
5th gear - 173 mph
6th gear - 213 mph
This is with the 5.88 increase from the 911r because of rpm, Grant showed.
2nd gear - 78 mph
3rd gear - 109 mph
4th gear - 140 mph
5th gear - 173 mph
6th gear - 213 mph
This is with the 5.88 increase from the 911r because of rpm, Grant showed.
03-09-2017, 01:45 PM
#25
Burning Brakes
Thread Starter
****, you are right. I confirmed elsewhere as well you must multiply the final drive by the constant ratio flipper gear due to being a transaxle. Doh!
I'm a moron. Certified.
I'm a moron. Certified.
03-09-2017, 01:50 PM
#26
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03-09-2017, 02:10 PM
#29
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