Jump to content

HELP NEEDED for KP36 Diff.


focus218

Recommended Posts

I have a 1985 KP36. I've made a lot of mods on it mainly on the mechanical part.

1. Changed the stock 2K for a 4K  motor (Brand new cylinder block)

2. Put a Weber DGV 32/36

3. Switched the T40 gearbox with a T50. 

4. Put new Headers and new Radiator with a low temp racing thermostat.

 

All these are great. The problem I have is on the freeway. My Differential is a stock KP36 (picture attached) one with a ratio of 43:10 (4.3) so travelling long distance is a pain and hard to reach top speeds. I need to get me a 3.9 ratio differential in so I will be able to cruise at 100-130 KMH with the engine at low RPMs.

Is there a way I can only switch my Final Diff Gears without removing my entire rear axle? 

Any suggestions ???

diag_AHU4Ce.png

Link to comment
Share on other sites

Members dont see this ad
3 hours ago, coln72 said:

Can you run a taller wheel/tyre combo....?

No. The factory tire settings were 165/65/12. The ones I have are 175/70/13 with extra 8 mm spacers in order for the front tires to not touch the shock absorbers. At the rear when I get some extra weight in, the tires escape the wheel arches just a few millimeters. So taller tires are not an option.

Link to comment
Share on other sites

Hi Michalis,

                    Off memory, the JAP 4.31:1 ratio diff was fitted to Corollas with auto transmission.  Manual transmission models, were often fitted with 4.11:1 ratio diffs.

The  3.89:1 ratio diffs were not fitted to any Corollas as standard, from memory.  However, I am led to believe, that the Datsun 1200 & 120Y series, used the 3.89:1 ratio diffs, of the same origin as Toyota, & that if you can get hold of a 3.89:1 crown wheel & pinion set new, a good diff reconditioning company should be able to swap them over, & lap them in for you.  A lot od Datsun 1200 utes had 3.89:1 ratio diffs.

Others on this forum may be able to confirm or correct my thoughts, as I haven't actually done it myself, but I do have it on my "bucket list", as I have a KE30 with a 1.43:1 ration diff in it, that I would love to fit a 1.389:1 diff into it.

Here is a listing I found, that has a number of 3.89:1 & 3.9:1 ratio diffs

http://www.difflap.com.au/ratios/gearratios_ad.htm

Cheers Banjo 

Edited by Banjo
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...