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Gear ratios explained

Discussion in 'Drivetrain' started by Stig, Dec 29, 2011.

  1. Stig

    Stig ST162 Guru Donated!

    Question -i don't understand how gear ratios work, but which boxes hit 100 or more kph in 2nd gear? i hate my s53 where first gear is to 50 and 2nd gear is to 90kph.

    A - You are lucky, the JDM boxes are even shorter
    Easiest solution is to fit way bigger rims/tyres or contact TRD and replace
    your final drive (diff) ratio


    I'm looking for a list of all "S" ratios - anybody seen one?

    Here's some ratios for the "E" series boxes - "S" is similar but expect differences
    Ratios: (Japan spec)
    1st 2nd 3rd 4th 5th Reverse Final Drive
    ST165 3.583 2.045 1.333 0.972 0.731 3.583 4.285
    ST185 3.384 1.913 1.333 0.972 0.731 3.545 4.285
    ST185 RC 3.583 2.045 1.333 0.972 0.731 3.545 3.933
    ST185 Rally 3.230 2.142 1.518 1.258 0.731 3.545 4.285
    ST205 3.384 1.913 1.258 0.918 0.731 3.545 4.285
    MR2 Turbo 3.230 1.913 1.258 0.918 0.731 3.545 4.285

    The best way to find the ratios is to count the teeth on each gear and divide the two to get the ratio
    On my JDM S53 box it is as follows:
    1st - 14/46 = 3,286
    2nd - 24/49 = 2,041
    3rd - 31/41 = 1,323
    4th - 35/36 = 1,028
    5th - 39/32 = 0.820
    Diff - 17/71 = 4,176

    At this stage I know the S54 5th ratio is the same and suspect it has a 3.9??? diff, it may be possible the other gears are the same as well - judging by the similarities in the GT4 boxes.

    So to summarize - the GE has a longer 1st, 2nd, 3rd than the GTE's but the GTE has a longer 4th and 5th gear
    ST185 RC is the fastest in reverse and has the highest top speed of all boxes.
     
    Last edited: Feb 15, 2012
  2. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    thanks stig, i don't know much about ratios so for your jdm s53, how does that translate into kph@redline per gear?
     
  3. Stig

    Stig ST162 Guru Donated!

    I know that the current S54 does 100ks in 2nd (just tried it), so the JDM S53 does around 90k's (check with Fernando)

    My old box (S53) did 100ks in 5th at 3200rpm,
    new one is 2800rpm at 100ks
     
  4. fernandocelica

    fernandocelica Well-Known Member Donated!

    yes kevin you are correct mine also does around 90k's at 6500 rpm in second and 5th at 3000 rpm get 100km and 180km +- 5500rpm I noticed the higher in kmp the better it become's I am happy with this gearbox ratio not sure what it is yet will soon find-out when I remove the motor and gearbox.
     
  5. Stig

    Stig ST162 Guru Donated!

    It's the normal JDM, I've opened 3 and all were
    1st - 14/46 = 3,286
    2nd - 24/49 = 2,041
    3rd - 31/41 = 1,323
    4th - 35/36 = 1,028
    5th - 39/32 = 0.820
    Diff - 17/71 = 4,176

    I think the O/S cars got a 3.9 diff with the same gearing.
    JDM S54 uses a 3.9 diff too with what could be the same gearing. (5th is identical)
    I'd like to open a late Camry box and see

    Here's my S54
    [​IMG]
     
  6. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    exactly what i have now!
     
  7. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    just looked at this again, my FE/5sp did 100km at 2800rpm as well...

    did FE's come with s54 and GE's s53? seems like it for usdm cars...
     
  8. Stig

    Stig ST162 Guru Donated!

    As far as I can tell the only difference between the S53 - S54 is the bellhousing and starter.
    Different regions get different gearing as well as FE/GE gearing differences.
    It seems that in 94/5 the S54 was updated to dual syncros but I'm at a loss to find anything on the LSD versions.

    Looks like all auto's had the same final drive (3.7)
     

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