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Old 12-01-2011, 11:31 PM   #1
Deslock
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Member#: 7959
Join Date: Jul 2001
Chapter/Region: NESIC
Location: western MA
Vehicle:
2013 BRZ limited
1999 Nova RTS

Default Guesses about Gear Ratios and Wheel Torque

This Subaru video shows 97 km/hr @ 7300 and 61 km/hr @ 3200:

That means redline is approximately at:
2nd 61 MPH
3rd 88 MPH
If we assume typical differences between gear ratios, we can speculate:
1st 40 MPH
4th 116 MPH
5th 144 MPH
6th 181 MPH
For highway cruising, that puts 75 MPH in 6th at 3100 RPM.

Peak wheel torque per gear, rounded to the nearest 10 lbf*ft, assuming 15% drivetrain loss:
1st 1700 lbf*ft
2nd 1110 lbf*ft
3rd 770 lbf*ft
4th 590 lbf*ft
5th 470 lbf*ft
6th 380 lbf*ft
Note that 4th-6th seem a little tall, but that's because 3rd is a bit tall in the video. Before noticing that 3rd was in the video, my guesses were:
3rd 86 MPH
4th 113 MPH
5th 141 MPH
6th 176 MPH
Obviously redline won't be reached in 6th gear, and possibly not in 5th if rumors of a 136 MPH top speed are true. However, some of those rumors claim top speed is due to fuel cutoff (supposedly at 7450 RPM), which raises some questions.

(P.S. I considered putting this over in the Transmission forum, but it seemed more appropriate in the BRZ forum since it's not an Impreza... mods feel free to move it as you see fit)
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Last edited by Deslock; 12-03-2011 at 03:36 PM.
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Old 02-24-2012, 10:19 AM   #2
fourmicah
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Interesting calculations, I guess we'll see what it comes out to. It would be cool if it hits 60 mph in 2nd gear.
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Old 02-24-2012, 10:54 AM   #3
Scooby South
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Location: 2013 Limited SWP BRZ and a
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99 Ver6 Recreation
JDM Speedwagon 3 LSDs..:)

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USDM is getting 4.10 Rear ratio
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Old 02-24-2012, 11:15 AM   #4
Dream20b
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The Fact that you have a sixth gear doesn't necessary mean it will go faster, The Rx8 i had slowed down from redline in fifth if you went to sixth gear and kept the peddle floored.
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Old 02-24-2012, 05:24 PM   #5
Deslock
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1999 Nova RTS

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This thread is months out of date as the actual ratios were released long ago:

Code:
gear   MT4.1    MT3.7    AT
1      3.626    3.626    3.538
2      2.188    2.188    2.060
3      1.541    1.541    1.404
4      1.213    1.213    1.000
5      1.000    1.000    0.713
6      0.767    0.767    0.582
rev    3.437    3.437    3.168
DR     4.100    3.727    4.100
USDM gets MT4.1 and AT. Tires are 215/45R17.

Approximate MPH at redline (7400 RPM):

Code:
gear   MT4.1  MT3.7  AT
1      36     40     37
2      60     66     64
3      85     93     93
4     108    119    131
5     131    144*   184*
6     171*   188*   225*

* = higher than rumored top speed

Note: Assumes "rolling radius" is 1% smaller than the 
calculated radius, but in reality rolling radius varies with speed.
Approximate peak wheel lbf*ft (6000 RPM):

Code:
gear   MT4.1  MT3.7  AT
1      1910   1740   1860
2      1150   1050   1090
3       810    740    740
4       640    580    530
5       530    480    380
6       400    370    310

Note: Rounded to nearest 10 lbf*ft.

Last edited by Deslock; 02-25-2012 at 06:36 AM. Reason: Added correction for rolling radius
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