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final drive gear selection

Discussion in 'Drivetrain' started by gwilliams41, Aug 22, 2011.

  1. gwilliams41

    gwilliams41 Guest

    i have been racing a celica gt that i put a 3sge engine in on a 3/8 mile race track, its a 1986 3sge mated to a 1988 celica st gearbox. from what i have read its a final drive gear of a 3.9xx and i have read there is a final drive of a 4.28 available does anybody know if this is a possible swap, i am racing in 3 gear with a 1.33 as i have read, i have alot of time reading on this and the more i read the more confused i get and alot of the info on the net is sketchy to say the least on this style of car. a final drive of 5.80 to 6.00 would be perfect and if i am close the 1.33 / 4.28 will equal a 5.7xx gear any and all help would be greatly appreciated
     
  2. 187flatliner

    187flatliner Seat Breaker Donated!

    stig would know this answer.
     
  3. Stig

    Stig ST162 Guru Donated!

    The JDM's are 4.2 diff's (4.17)
    3rd is also 1.3

    TRD etc also sell kits and have a wider range - very pricey
    [​IMG]

    It's a complete rebuild as you have to change the secondary shaft and crownwheel
    [​IMG]

    You can also buy LSD's for these boxes
    [​IMG]

    It's possible to change all the gearing as well but involved as the 1st 3 gears are usually machined to a shaft
    For racing I always built my boxes with longer lower gears and shorter higher gears -
    less changes and wheelspin down low and more power at speed = quicker lap times

    For the ideal box I'd buy boxes from a Camry, Corona, gen2, MR2, JDM etc.
    Strip them all and then combine the gears and diff I wanted.
    Often manual diesel boxes can yeild some interesting variations and very long diffs, not sure about the Corona diesel box?
    On an oval you'd want to hit redline just before climbing on the brakes,
    another cheap and legal "cheat" is to use a JDM ecu for an extra 10-20hp which could mean redlining the 3.9 diff instead of costly box mods

    Follow my menu for more info and pics
     
  4. gwilliams41

    gwilliams41 Guest

    i appreciate the response on this i called trd in cali today and they was of no help and say the only go back as far as 95/96 on the years, on the jdm ecu is it a instant horsepower gain, and does it have the rev limiter still, i have read somewhere about a 20 mghz crystal that controls the rev in the factory ecu and it can be changed to gain close to 1000 more rpms, if thats the case i could bottom feed around the track and shorten it up and really be a thorn in them h22 hondas sides, it would probably only hit 8100, or so
     
  5. Mafix

    Mafix Owner Staff Member Administrator Donated!

    use a jdm computer. they don't have a rev or speed limiter.

    and with the 88 st box (3sfe) that should be a 4.11 final drive.
     
  6. Stig

    Stig ST162 Guru Donated!

    Best to speak to jwagner about this.
    His race car thread is gone but he was very impressed with the JDM ecu.

    For oval I think torque & midrange is more important for getting out of corners and acceleration
    on the straights will get you past other guys.
    It's easier to pass under acceleration than when braking
     
  7. Seank90

    Seank90 Well-Known Member Donated!

    euro ECU doesnt need a o2 sensor , and will probably give more horsies than the JDM
     
  8. gwilliams41

    gwilliams41 Guest

    i would like to try a jdm ecu but where would i even begin to find 1 here in ohio. i seen jwagner had a celica he is stock car racing as well, i have access to quite a few 5th gen celicas, and i have 1 complete 4th gen gts left to scavage for driveline only parts it has a running 3sge/5 speed that runs smooth as can be, and smokes enough to kill skeeters from 200 miles away. hopefully jwagner knows some tricks he would share. the car i have now is gutted to nothing, 8 point cage, i made coilovers from the stock struts and have afco racing springs on all corners, front and rear adjustable swaybars, an 205/50/15 falken azenis on her, right now we are about .6 off v8 stocks trackrecord and we are racing anywhere from .35 to .60 off there race times and some of them just shake there heads at the times considering they are 500 hp and up for that slight difference. if any of you are interested you can youtube a guy called JMAN videos he shows the races on there it will be kil-kare speedway compacts you will see the black #41 thats the car there its a 8year old stocker and she has the dents to prove it
     
  9. jwagner162

    jwagner162 Well-Known Member Donated!

    -ahhh the jdm ecu. yep, instant h.p. a very dramatic improvement. with the added h.p. my gearing was near perfect for the road course we ran. id top out 3rd of the straights just in time for turn 1 and would be maxing 2nd through the tight sections. my thought would be that even if you raise redline your making max power well before.

    -i know circle is a bit different, but other than the ecu the biggest gains i found in the 162 was in the brakes. theres quite a bit to be desired from the stockers and i had huge issues with boil-off/fade. i honestly probably gained more time from messing with that than anything else....and still never got them were i wanted.

    -the auto-x guys seem to be getting slightly better times with the dunlup direzza than the azenis, but no personall experience with them.

    -seans right on the euro. however the euro ecu is made to compliment higher comp pistons, different cams and afm. though all of it would be "stock". you may be able to get some one in the correct market to source you that stuff. i always wondered if you could have someone check at the dealer to see if pistons were available.

    -pm'd aswell.
     
  10. Seank90

    Seank90 Well-Known Member Donated!

    different cams aswell?
     
  11. Stig

    Stig ST162 Guru Donated!

    Cams/afm are the same worldwide afaik, all apart from the JDM use EGR
    Not sure if you deleted EGR yet?

    The "euro" version is actually common worldwide - it is known as the "GT" and pistons
    are similar to the gen2
    Easily identified by darker gold rocker covers, there is one in the yards atm,
    I doubt the ecu is different. Rear badge reads GT-i 16 valve (euro) and 2.0 GT (JDM)
    The pistons are available from Teikin (pn 46663) (oem pn 13101-88362)

    Pistons were approx:
    GE - 9,3CR
    GE (GT) - 9,5CR
    GE gen2 - 9,8CR
    GE gen3 - 10CR
    GE Beams - 10,5CR

    I have access to a spare JDM ecu and there's a set of good gen2 pistons in a motor I just bought.
    It also has a gen2 header set, but you could just as easy use pacesetter or hotshot headers
    as the stockers sukk bad and are prone to cracking as well as being obese
    (eliminating as much weight from the front as possible will improve times)

    The brake problem is easily solved - delete the dust covers, if that fails I recommend
    ST202 brakes and master cylinder
     
  12. jwagner162

    jwagner162 Well-Known Member Donated!

    -from what i could find on toyodiy. the euro has different p/n's for for cams, ecu, afm, and pistons... iirc. its not all euro however, its just like half the markets in euro. while all the rest of the markets have the same p/n's for everything but the ecu, including some euro, jdm, usdm, aud, ect...

    -i may be wrong on the cams, but cant remember.
     
  13. gwilliams41

    gwilliams41 Guest

    stig is that spare jdm ecu for sale, i found a ecu on ebay but i wonder what the time span and shipping would be to the states, there was 1 in australia and 1 in uk, my engine is getting old so i have thought about rebuilding it but have also considered doing a 3rd gen swap as well, but if the jdm ecu gets me around 150-160 dont know if i would do a swap for 10 hp,also was curious if a 2nd gen head on the 1st gen block with tvis would show any gains
     
  14. Stig

    Stig ST162 Guru Donated!

    You found JDMs in UK & OZ?

    Yes, but I didn't have $150 spare at the time

    You can't use gen2 with TVIS
    I'd use the gen1 and get the gen2 cams cut down slightly (too much lift) or use the whole gen2/3 head
     
  15. jwagner162

    jwagner162 Well-Known Member Donated!

    -you have to make sure the p/n is correct. as there are a few #'s that will work. ive been finding that pretty much anything from a jap auto maker is now listed as a jdm part on e-bay ect even if its a usdm part. and people will buy it.

    -great example is this guy from my work. has a sw20. always buying "jdm" parts. he just got his new jdm momo steering wheel. i asked him why he didnt just get one from italy. he got the facepalm.
     
  16. Stig

    Stig ST162 Guru Donated!

    Looks like we'll have to re-do thread we spent so much time compiling on ECU's
    The first few pages are missing completely
    http://www.st162.net/forums/viewtopic.php?f=48&t=5811

    There are a multitude of ECU's available for these motors, the JDM is a unique p/n
    What were the no's on those ECU's?
     

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