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Thread: PAR gearset/Nismo LSD ratios

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    Leroy Peterson's Avatar
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    PAR gearset/Nismo LSD ratios

    my 32a gearbox has 1st-5th PAR straight-cuts (synchro) and a Nismo 1.5 mech LSD.
    I'm hoping to work out the gear ratios and final drive.

    The website says custom ratios are available: http://www.par-engineering.pl/index....=article&id=48
    After plugging some figures into a calculator, the closest figures (from my driving experience) are listed here on PGA: http://www.users.on.net/~paullus/pul...arboxinfo.html
    PAR straight cut gearset:
    1st 3.1
    2nd 1.93
    3rd 1.28
    4th 0.956
    5th 0.810
    Final 4.167:1
    Where did these figures come from? is it most commonly recommended by PAR, even though it differs from the PAR website?

    But my 5th gear is long as fark.
    The previous owner once said it was longer than N14 5th gear, and ive done 220-240 (speedo accuracy, is there such a thing?) in 5th gear at no more than 5,500 rpm. Even with lots of power its just doesnt gain much speed in 5th.

    what would the likelyhood of the final drive being changed when the gearset or LSD were fitted?

    nameplate 4.1:

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    PAR make numerous gear and final drive ratios - so anything could be in the box

    The ratios you've listed:
    1st, 2nd and 3rd are custom
    4th, 5th and the final drive are basically same as stock

    You'll be able to work out the overall gearing for each gear by feeding engine RPM and road speed through some maths in Excel
    If you don't know what the final drive ratio is it will be hard to work out the individual gear ratios

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    Leroy Peterson's Avatar
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    yeah, and to add to the complications are the speedo errors. I guess recording rpm in each gear at speeds less than 80km/h should help narrow it down a bit.

    Whats PAR's philosophy on the crown and pinon shaft? is it just a strengthened version of stock or does it compliment the gearset?

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    I've got a stock ratio 5th gear on my PAR gear set, it's 0.755

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    PAR have changed their ratios a few times and have done custom ratios for people, but here are mine anyways, maybe this info can help you

    1st 3.11
    2nd 1.846
    3rd 1.235
    4th 0.956
    5th 0.755 (Stock)
    Final 4.176 (Stock)

    I know these are my ratios for a fact because I've put the teeth through a gear ratio calculator

    Tooth count on each gear and opposing gear:

    1st 9/28
    2nd 13/24
    3rd 17/21
    4th 23/22
    5th 45/34
    FD 71/17

    When I got the box it had a PAR pinion shaft which I snapped and replaced with a Nissan one, the ratio for the PAR one was 4.428, 62/14 teeth, this and the stock ratio is what most people have gotten with their PAR boxes
    Last edited by Boosted VLAD; 30-10-2015 at 06:34 PM.

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    I would get a gps and get a friend to write down the speeds at A SPECIFIC RPM in each gear,
    Go to a website that accounts for gear ratios, final drive and tyre height and have a play around and see if you can get a match,

    You can obviously find out your tyre size and you have 2 likely final drives to play with on the calculator,

    Unless you want to go pulling the box apart, which I doubt you would just to figure out the ratios.....
    Last edited by Boosted VLAD; 30-10-2015 at 03:58 PM.

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    Leroy Peterson's Avatar
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    Hmmm thanks for the info.
    I need ratios and final drive for my ecu. The more accurate the better

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