Differential ratios for the 1uzfe

Discussion in 'Drivetrain (Members Only)' started by drifty325i, May 23, 2007.

  1. drifty325i

    drifty325i New Member

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    Hey im almost ready to tune the V8 with the link (will post up pics this weekend [​IMG])
    But i no ill have to change the ratio in the lsd to suit the torque,power and gearbox of the new motor.

    Now it currently has a medium case

    A)3.73 lsd,
    225/45/16 tyres
    final drive ratio of 0.86

    Giving me an open road of 3074rpm @110kph in 5th

    Now as you could imagin this does not suit a 300hp v8 in a car that weights around 1185kgs.

    Im thinking a diff swap to
    [​IMG]3.23 lsd
    this will give me a open road of 2662rpm @110kph

    or

    C)2.93 lsd

    open road of 2414rpm @110kph

    What are your guys thoughts? [​IMG]

    Cheers
    Riley
     
  2. Peewee

    Peewee Moderator

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    What are you planning to do with the car?

    If its staying NA, keep the ratio.
    If its going turbo/super, put in the 2.9
     
  3. mshawari1

    mshawari1 Member

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    I will go with 3.23 lsd !!!
     

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  4. gloverman

    gloverman Well-Known Member

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    Get it driving then decide which diff to use. It is had to make a decision without driving it with what you have and changing the diff is not a big job to do later - Cheers
     
  5. drifty325i

    drifty325i New Member

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    Thanks for you input guys, ill drive her first them make up my mind on the ratio. im sure the 3.23 will be the go tho
     
  6. cribbj

    cribbj "Supra" Moderator Staff Member

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    You might want to look at your speeds in all gears before you decide on the final drive ratio.

    Maybe your first gear is really loooonnnng, and if so, you might need that higher final ratio. On the other hand, if your first gear is nearly useless because it's so short, then go with the lower final ratio.


    Here's a handy downloadable ratio/speed calculator:

    http://www.gearboxman.co.uk/download/gearspeeds.v2.xls
     
  7. Peewee

    Peewee Moderator

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    To me, if you are staying NA, and only going for 300hp, then anything taller than 3.73 will be boring (ie the 3.23 or 2.93).

    My car is 'only' 1300kg, and I only have 235's on the rear, and I can use full throttle in first without tyre spin (providing I launch correctly). Also when I snap 2nd gear it only chirps, it doesn't step sideways.

    With a taller diff ratio the car would be more boring, as it doesn't have the torque to pull it hard.

    Sure your car is ~150kg lighter, but thats not a huge amount. With some nice wide sticky tyres I believe a 3.73 would be perfect.
     
  8. 91_4x4runner

    91_4x4runner New Member

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    I've got to agree with Peewee. If you aren't going to go forced induction, the car simply won't have enough torque to push it as fast as it could with the 3.73 (or similar)...

    You're going to have to drive it to see how well it matches up and decide from there...
     
  9. mycarhasposessedme

    mycarhasposessedme New Member

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    (A)3.73 or (D)3.89
     
  10. jibbby

    jibbby New Member

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    What exactly is your current setup consist of?... Are you running a manual or automatic tranny and what type? What is the torque specs of your motor? More info is needed......Also what are your goals? Topend or Lowend power and speed?
     
  11. drifty325i

    drifty325i New Member

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    Its a 1170kg bmw e30 motorsport coupe, running a toyota w55 gearbox with a final drive of .86 and my current diff is a 3.73 lsd. Not 100% sure on the torque specs of the motor, its a 1996 high comp 1uzfe with extractors,exhaust, full proper cai intake,full aftermarket computer,will run 98 octain with the tune to suit. Want it to rev well, be quick and relaible, good pART TIME track/road car
     

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  12. jibbby

    jibbby New Member

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    I am not sure what the W55 gearbox is exactly, but I can say the good ole toyota Supra TT 93-98 Torsen LSD has a nice Differential ratios.. If the W55 is anything like the R154 or V160 trannies then the 93-98 Torsen Supra TT manual Differential gearing ratio's would be my choice for your setup...

    Not much help sorry Drifty.. Best of luck finding the best dif. ratio for your needs...
     
  13. Peewee

    Peewee Moderator

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    Honestly Jibbby, if you know you have no idea, its best to not answer.

    The TT diff ratio on the JZA80 Supra (3.2ish) is purely setup for the 6 speed box.
    If they ran the 'traditional' 3.7ish ratio you'd be forever changing gears.

    And if you ran a 5 speed with the 3.2ish ratio, and you don't have masses of torque at your disposal (ie, from a TT 1UZ, or high boost TT 2JZ), then you'd be out of the power band on almost every gear change.



    Drifty, as you probably know the W55 has shorter gears for 1st and 2nd compared to the W57/W58. 10% shorter acutally, which means that you could run a 10% taller diff without much compromise.

    With that in mind, I'd probably got the W58/3.73 setup, or W55/3.45 setup.

    I still personally feel that the car will not pack enough of a punch with a diff any taller than 3.45:1.
     
  14. jibbby

    jibbby New Member

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    Peewee are you picking on me? I think I got a couple of pairs of boxing gloves in my closet if you want to go toe to toe? :eek:p:

    I guess your right anyway I shouldn't have posted that garbage.... I must have been looking for attention or something.. My bad..:tapedshut:
     
  15. drifty325i

    drifty325i New Member

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    Lol all good guys thanks for you inputs. Peewee i think your on to it tho mate cheers
     
  16. 016UCH

    016UCH New Member

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    I know it's silly to resurrect this after 11years, but was it sorted? Wat diff ratio was finally decided upon?

    Reason I ask is that I'm in kinda the same boat. 1uz in ae70. W57, 195/50-15 ... I want it to be really quick but still drivable on the highway. ...
     

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