Testing if your speedo is out (well, Guestimate if it is...)

[PaulW]

Was on a Private Test Track last night... :twisted: doing a bit of a test see what I could get out of the corsa... had an indicated 130-ish mph @ 6300rpm... thought my speedo was reading wrong...

so after asking on another forum, I found a program & checked my ratios for the gearbox (F15/CR) and got these results...

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Wheel rim size        14   Tyre section   185  Aspect ratio 65
Enter diff ratio      3.74 Wheel diameter 23.468
Enter 1st gear ratio  3.73                        Type 9 Standard ratios
Enter 2nd gear ratio  2.13
Enter 3rd gear ratio  1.41
Enter 4th gear ratio  1.12
Enter 5th gear ratio  0.89
                              Enter rev limit 6500          <rev>
                                                    Limit   <change>
            1000 2000 3000 4000 5000 6000 7000 8000 6500    500-600-700-800-650
1st (3.73 )  5.0   10   15   20   25   30   35   40   33    285 342 399 456 371
2nd (2.13 )  8.7   18   26   35   44   53   61   70   57    330 397 463 529 430
3rd (1.41 ) 13.2   26   40   53   66   79   93  106   86    397 476 556 635 516
4th (1.12 ) 16.6   33   50   67   83  100  117  133  108    397 476 556 635 516
5th (0.89 ) 20.9   42   63   84  105  126  147  168  136


Revs @ 60 mph in 4th 3599  Revs @ 70 mph in 4th 4199
Revs @ 60 mph in 5th 2860  Revs @ 70 mph in 5th 3337

so then worked out seperate myself to 6300rpm with the above ratios & got a confirmed 132.7MPH...

if you want information & speeds regarding your corsa, please let me know what gear & RPM you were pulling (you need a rev counter), and also the dimensions of your wheels & tyres, and I\'ll sort the maths out for you...

alternatively if you wait till tonight, I\'ll upload the EXE which does all this for you & then you can check yourself.

[jsc]

nice work mate

[PaulW]

Right I\'ve uploaded the Program here...

http://www.corsa-b.co.uk/misc/GEARING.EXE

Its an old DOS Program, and if your running Windows XP/2000, you will need to full-screen it for the pointer to display properly...

Also, here are the Gear Ratios for various Corsa B Gearbox\'s...

Engine/Gearbox Matchings
Pre- 1995 Model

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Engine Code            Gearbox Code
12NZ                   F10/5 WR
C12NZ                  F10/4 WR or F10/5 WR
X12SZ                  F10/5 WR
X14NZ                  F10/5 WR
C14SE                  
  (Combo Van Model)    F10/5 WR
  (Hatchback Model)    F13/5 CR
C16XE                  F15/5 CR

1995 Model Onwards

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Engine Code            Gearbox Code
12NZ                   F13/5 WR
C12NZ                  F13/4 WR
X12SZ                  F13/5 WR
C14NZ                  F13/5 WR
C14SE                  F13/5 CR
X14XE                  F13/5 CR
X14SZ                  F13/5 CR
C16XE                  F13/5 CR
X16XE                  F15/5 CR

Gear Ratios
F10/4 and F13/4 WR Gearbox:

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Gear       Ratio
1st        3.55
2nd        1.96
3rd        1.30
4th        0.89
Reverse    3.31

F10/5 and F13/5 WR Gearbox:

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Gear       Ratio
1st        3.55
2nd        1.96
3rd        1.30
4th        0.89
5th        0.71
Reverse    3.31

F13/5 CR Gearbox:

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Gear       Ratio
1st        3.55
2nd        2.14
3rd        1.43
4th        1.12
5th        0.89
Reverse    3.31

F15/5 CR Gearbox:

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Gear       Ratio
1st        3.73
2nd        2.13
3rd        1.41
4th        1.12
5th        0.89
Reverse    3.31

Differential/Final Drive Ratios (typical)[/b]

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Gearbox Code                    Ratio
F10/4 and F13/4 WR              3.94
F10/5 and F13/5 WR
  All Except X12SZ Engines      4.18
  X12SZ Engine Models           3.74
F13/5 CR                        3.94
F15/5 CR                        3.74

If I\'ve missed any out, please let me know! I\'ve only covered \'standard\' models here, and not conversions, as I dont have the data for gear ratios & such for the big-block gearbox\'s.

This would be good to check out how much your speedo is out by, as you can run the program & enter your standard wheel sizes, and then do it again with the sizes of alloys & low-profile tyres your using...

Quite clever really!

[scatt16v]

Thats wrong.

[PaulW]

whats wrong??

[Joff]

F16W
1st 3.42
2nd 1.95
3rd 1.28
4th 0.89
5th 0.71

F16C
1st 3.42
2nd 2.16
3rd 1.48
4th 1.12
5th 0.89

F20
1st 3.42
2nd 2.16
3rd 1.48
4th 1.12
5th 0.89

[AK]

rev counters over read quit a bit paul

[PaulW]

fair enough!!

I was running over-sized tyres at the time (65-profile) since putting the 60-profile on it does read differently & over-read...

[scatt16v]

Yeh, it says mine is revving at 3,163rpm in 5th @ 60mph, but its actually revving 2,800rpm

[fozzmanracing]

just use a sat nav