RPM vs KM/HR

Discussion in 'Honda' started by Nabunaga, Sep 15, 2015.

  1. Nabunaga

    Nabunaga Senior Member
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    Hi bro's,

    Im looking some data from u guys as a comparission.I think my rpm a bit high during 5th gear on highway.

    My setup:
    Engine: b18c
    FD: 4.4
    5th gear: 0.787
    Tire: 195/55/15


    RPM( on 5th gear)
    2k = 58km/hr
    3k = 82km/hr
    3.5k = 100km/hr
    4k = 111km/hr
    4.5k = 123km/hr
    5k = 140km/hr
    5.5k = 158km/hr
    6k = 175km/hr
    6.5k = 180km/hr

    AppreciTe if u guys can give some feedback (rpm vs km & setup)Thanks..
     
    #1 Nabunaga, Sep 15, 2015
    Last edited: Sep 15, 2015
  2. ^pomen_GTR^

    ^pomen_GTR^ Senior Member
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    check your speedo with gps speedometer first.... it too far differences (usually 10kmh-6kmh range) then u need to swap into smaller final drive.... atleast 4.1 or probably 3.8
     
  3. 6UE5t

    6UE5t Senior Member
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  4. vr2turbo

    vr2turbo 5 Year | Silver
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    If speedo meter is correct then to reduce rpm will have to change the gear ratio......
     
  5. Nabunaga

    Nabunaga Senior Member
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    already check with gps, speedo meter is correct, i was thinking to change the FD to 4.2, but im worries my car will be slow for initial gears. Correct me if im wrong, but i never found 4.1 or 3.8 FD for Honda. It seem too small.

    Pomen GTR: appreciate if u could share u reading, 2-6k rpm.

    Vr2turbo: my 5th gear (0.787) is the smallest ratio available for B series gearbox.

    6uE5t: thanks for the link,
     
    #5 Nabunaga, Sep 17, 2015
    Last edited: Sep 17, 2015
  6. vr2turbo

    vr2turbo 5 Year | Silver
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    Yup, saw the 5th gear ratio, also wondering why your rpm still high?:hmmmm:
     
  7. Nabunaga

    Nabunaga Senior Member
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    that why, if someone could share their rpm vs km, it will be nice for my study n understanding :)
     
  8. ^pomen_GTR^

    ^pomen_GTR^ Senior Member
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    i think you car already have correct rpm-speed reading


    Honda Tranny Gear Ratios

    Specnically Speaking: B-series Gear Ratio Guide + More!


    if u want lower cruising rpm...then try scouting for the 4.266 final drive :driver:
     
  9. Nabunaga

    Nabunaga Senior Member
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    it look like a a same, but actually not the same, during testing, he did't mention:
    1) Engine capacity (i believe different cc will giving different speedo meter reading, eg: b20 will not same as b18c)
    2) Different tire size giving different speedo reading
    3)Different FD also result different reading

    thanks pomen GTR for link given
     
  10. ^pomen_GTR^

    ^pomen_GTR^ Senior Member
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    cc/engine size not affecting any speed-rpm reading.....it just change the powerband....

    example like b16a use 4.4 final, 0.787 5th gear, swap with b18c or b20 using the same gearbox will result same speed-rpm reading....but sure with b20 u will felt like engine screaming due to extra torque/power at that rpm range....
     
  11. vr2turbo

    vr2turbo 5 Year | Silver
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    Yup, agree with bro. pomen, engine capacity does not change the speed vs rpm, however tyre size does but then if change within limit the speed change is very small only and should be around 3% max, unless really over sized but then also to 5% or so only
     
    #11 vr2turbo, Sep 17, 2015
    Last edited: Sep 18, 2015
  12. Nabunaga

    Nabunaga Senior Member
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    yeah, u may right, but still im looking for the data for comparission :)
    appreciate if anyone could share :)
     
  13. ^pomen_GTR^

    ^pomen_GTR^ Senior Member
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    for comparison..

    my satria 1.6 (A) 195/55-15 tyre

    4th gear (final gear in auto) 0.712
    final drive ratio of 4.042

    @3000rpm, speed = 125km/h

    _________________________________________

    my scooby 2.0 (M) 235/45-17 tyre

    gear ratio:
    5th 0.738
    Final 4.444


    @3000rpm, speed = 100km/h



    both speed true on speedo (+- within 3km/h range verified on gps)
     
  14. Nabunaga

    Nabunaga Senior Member
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    tq for sharing :proud:
     
  15. g4i8y0t

    g4i8y0t Senior Member
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    My B16a EK4 engine with S4C manual transmission has exactly the same RPM vs KM/H as yours. I'm using R15/55/195 tire.
     
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  16. vr2turbo

    vr2turbo 5 Year | Silver
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    All depends on gear ratio. Even though my SUV is 4 speed auto but at 110km/h rpm is below 3k
     

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