Jump to content


Photo

FJ20t gear ratios


  • Please log in to reply
66 replies to this topic

#1 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 20 June 2013 - 03:45 PM

I'm wondering if anyone knows what ratios FJ20t boxes have? I done a bit of research and seem to get different answers. Ideally I'd like ratios close to a 260z box, .8 fifth is a must!.

How accurate is this? According to this info the ratios aren't too bad.
http://members.optus...e10/gearbox.htm

#2 dat2kman

dat2kman

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 4,030 posts
  • Location:Newport Waters Qld
  • Tagline:going sailing, see ya later!

Posted 20 June 2013 - 06:19 PM

Dont use a fj turbo box thenratios are stocko L series.ie 3.3 first.

Grab a 260 box first should be 2.9.
Or,,i have a complete L type close ratio, 2.6 first,,,
Or,,,
I can sell you a new 2.4 close ratio gearset, you fit it into some stocko L series box,,,
Or,
,
,
,
Or, dunno, my brain hurts!

#3 peter mc

peter mc

    The 1000+ club

  • Members
  • PipPipPipPipPipPip
  • 1,573 posts

Posted 20 June 2013 - 07:51 PM

the reason we use the fj20t box is so we can use the wide gear , because the stock L gear size just wont hold up with the torque  the motors are making , the fjt box with a gear set from kameri is a good thing ,

#4 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 20 June 2013 - 08:31 PM

My current 260z box has now just started to get bearing noise on top of the other issues.

With the site above the FJ20turbo box ratio's are 3.657, 2.177, 1.419, 1.000, 0.833

I wanted to avoid buying new gearsets and use that money to rebuild the newer box.

#5 benny

benny

    The 1000+ club

  • Members
  • PipPipPipPipPipPip
  • 1,733 posts
  • Location:Peninsula Area - VIC

Posted 20 June 2013 - 10:13 PM

My current 260z box has now just started to get bearing noise on top of the other issues.

With the site above the FJ20turbo box ratio's are 3.657, 2.177, 1.419, 1.000, 0.833

I wanted to avoid buying new gearsets and use that money to rebuild the newer box.



why dont you go with a newer sr or z32 box??

#6 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 20 June 2013 - 10:26 PM

I thought the FJ box had the same size gears as SR?

#7 peter mc

peter mc

    The 1000+ club

  • Members
  • PipPipPipPipPipPip
  • 1,573 posts

Posted 20 June 2013 - 10:34 PM

they have the same size gear Gareth , there 20mm wide 260 box is 18 , also the gear sets have better gear strenth , also the bearings are the same as the sr box  , its only when you go to the rb25 and vg30 boxes that you get a bigger gear sets and bearings , much stronger but much harder to fit to the L motor ,
the fj t box with a gear set is more than up for your engine mate ,

#8 benny

benny

    The 1000+ club

  • Members
  • PipPipPipPipPipPip
  • 1,733 posts
  • Location:Peninsula Area - VIC

Posted 21 June 2013 - 12:08 AM

surely a sr box would be cheaper then an fj too?? A guy in the states makes a kit to hook up a z32 box. See here for info -http://forums.hybridz.org/topic/101735-z32-transmission-adapter-kits-for-l28/

#9 peter mc

peter mc

    The 1000+ club

  • Members
  • PipPipPipPipPipPip
  • 1,573 posts

Posted 21 June 2013 - 08:20 AM

with the sr box you also have to mod the floor and shifter hole and the plastic need work to fit the shifter , with the fj box  the shifter is like the L box  no mods needed  only have to swop the bellhousing

#10 d3c0y

d3c0y

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,847 posts
  • Website:http://garagesanmaru.com
  • Location:Brisbane
  • Tagline:Forum Jerk

Posted 21 June 2013 - 08:25 AM

Don't forget you have to shorten the tail shaft too with the SR.


With the Z32 even after you get the adapter which is close to $500 landed you still need to:
"This adapter is for the DIY crowd and will require machining the z32 [/size]__af_placement_id--[AFF-PLACEMENT-ID].html]bellhousing[/size] and fabrication of a transmission mount and [/size][url=http://www.ebay.com/sch/eBay-Motors-/6000/i.html?_nkw=driveshaft]driveshaft[/size] along with shortening the shifter linkage."
[/size]
[/size]If he wants a 0.85 5th then you will have to change the 5th gear too and at the end of the day it may still need a rebuild as 3rd and 5th syncros are a bit notorious in these boxes.
[/size]Z32 gear ratios:
[/size][table][tr][td]1st gear ratio:[/td][td]3.214:1 man / 2.785 auto[/td][/tr][tr][td][/td][td][table][tr][td][/td][/tr][/table][/td][/tr][tr][td]2nd gear ratio:[/td][td]1.925:1 / 1.545 auto[/td][/tr][tr][td][/td][td][table][tr][td][/td][/tr][/table][/td][/tr][tr][td]3rd gear ratio:[/td][td]1.302:1 / 1.00 auto[/td][/tr][tr][td][/td][td][table][tr][td][/td][/tr][/table][/td][/tr][tr][td]4th gear ratio:[/td][td]1.000:1/ 0.694 auto[/td][/tr][tr][td][/td][td][table][tr][td][/td][/tr][/table][/td][/tr][tr][td]5th gear ratio:[/td][td]0.752:1 / na auto[/td][/tr][/table][size=14px]

#11 peter mc

peter mc

    The 1000+ club

  • Members
  • PipPipPipPipPipPip
  • 1,573 posts

Posted 21 June 2013 - 09:16 AM

Gareth the ratio we use in the fjt box are    2.43  1.68  1.26  1  .86 or .75 and we use a 4.3 diff with it  for most L motors


#12 dat2kman

dat2kman

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 4,030 posts
  • Location:Newport Waters Qld
  • Tagline:going sailing, see ya later!

Posted 21 June 2013 - 09:39 AM

They're Albins ratios.

With SR box, they are 50 mm longer o/all, ie need to shorten tailshaft by 50 mm
The gearstick in a sr box will come up in centre of gearstick hole in floorpan of 260 shell.
The box to floorpan mount is 30 mm rearwards compared to L box in a late 240 or 260 floor.

Early 240 floor ( old style box mount) much easier, just drill two new holes in floor, ans a couple bits of rectangular 4 mm thick plate and usual bolts.
Later, use a couple pieses 120 mmx80 mm 12 mm thick rubber, and a piece of 6 mm pate, drilled with four holes to allow for 30 mm offset, the stock 260z box to floor mount gets two holes drilled in the dimples. Pretty easy.

Yes the sr as well as ca or rb and fj box will need a sr bellhousing, a bit of jiggling around with front countershaft bearings, and check the 1/2selector rod diam as bell may need a 16 mm drillbit into the CORRECT selector support hole.

For cluster clearance either plunge face cut inside of bell by 2 mm ( makes it weak, i dont like that) or,
Remove/modify the anti rattle tooth gear at front of lower countershaft.

If wanting to use rb20det box, stick comes up at front of the gearhole, but tailshaft remains stock, ie rb20det box is same length as L B type box, BUT these have a .75 fifth. Same with VL commo ( rb30) non turbo
The sr boxes have a .83 fifth

Gareth if you are after any of these, i have a few of each, and can supply close ratio sets for any of them.

#13 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 21 June 2013 - 01:24 PM

Pete, is that an aftermarket gear set?

Is there a specific model or any way of telling which FJ box has the .83 fifth gear? I'm only running a 4.1 FD so won't want any bigger overdrive.

Jason & Pete, could you pm what sort of price I'd be looking at for an FJ gearset? It may not be in the budget to do a full gear set, so I may just end up changing 5th if its .75

I like the idea of the FJ box, seems less work, smaller and lighter than later models?

#14 d3c0y

d3c0y

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,847 posts
  • Website:http://garagesanmaru.com
  • Location:Brisbane
  • Tagline:Forum Jerk

Posted 21 June 2013 - 02:44 PM


I dont see how the FJ box will weigh any different or be smaller than an RB or SR box, but is the easiest to fit, this is why i went this way.


Budget around $3500 for a rebuilt box with a gear set in it.

#15 NZeder

NZeder

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,291 posts
  • Location:Auckland, NZ

Posted 21 June 2013 - 03:10 PM

If installing the Kameari gear set into an FJ B box why not just install the Kameari gear set for the L6 B box?? surely they are the same gear set?

#16 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 21 June 2013 - 04:49 PM

$3500 is double my price range, I don't want a new gear set if I can avoid it.

I guess I need to try and find which cars had the FJ box with the .83 fifth gear. Buy one and get it rebuilt.

#17 dat2kman

dat2kman

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 4,030 posts
  • Location:Newport Waters Qld
  • Tagline:going sailing, see ya later!

Posted 21 June 2013 - 06:18 PM

I got a couple of fjt boxes here, you dont need bellhousing, swap your bell over.

I'll pull them out over weekend and check them over, and make sure they have the 5th you want.
Easy enough to crate it up and get it to a transport depit near you,

IIRC, both are in pretty good cond, may not need anything, just bolt in and go!

#18 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 21 June 2013 - 06:27 PM

Pm sent

#19 NZeder

NZeder

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 2,291 posts
  • Location:Auckland, NZ

Posted 21 June 2013 - 06:47 PM

what box have you got right now? A box or B box? I know RB 71C you can swap over the 5th - so I assume the B boxes are the same too - I would have to check part catalogues to see if the numbers are the same etc. So if the 71B are like the 71C you should be able to take the 240z/260z 5th and put that on the FJ - 5th is usually the same size/width well the are in the 71C IIRC.

#20 Gareth. J.

Gareth. J.

    The 2000+ club

  • Members
  • PipPipPipPipPipPipPip
  • 3,237 posts
  • Location:Melbourne, Victoria

Posted 21 June 2013 - 07:10 PM

I have a 260z box, but its quickly becoming junk, the syncros are very very tired. I have recently found what looked to be a gear tooth (4mmx5mm chunk) in the oil. 2nd to 3rd up shift on track sounds like a sequential box.

I have also seen someone strip 5th gear on track, locked the box and rear wheels completely. I ran in the same group as him at nationals and was able to see I an now a fair bit quicker. Got me thinking.

I thought if I'm going to rebuild a box I may as well get something a bit stronger.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users