l am after p/x on my 6 speed jap spec dccd box and 3.9 rear diff,this comes with the prop to fit to a classic shape impreza (these came out of my ra),i am after a uk 6 speed box in very good condition plus cash,no prop or diff required and buyer to collect from my end,l'm not 100% sure what this will be worth but with the diff prop and dccd i'm assuming a fair bit more than just a uk 6 speeder,i may take an offer to buy outright but would prefer a p/x,but stress no stupid offers as a **** off often offends,
cheers steve

 

are the UK and Japanese rear diffs the same ratio?

 

hiya paul hope you had a good xmas buddy,posted this on leggy forum too......
the uk final drive is 3.545 the same as our legacy's which will make the fitting a little less of a ball ache,the jap ratio is 3.9 which gives a little bit quicker gearing helping acceleration.
cheers matey
steve

 

up

 

up

 

up

 

both final drives are actually 3.9

JDM - Front diff is 3.9:1 - Drop gear is 1:1 - Rear diff is 3.9:1
UK - Front diff is 3.9:1 - Drop gear is 1.1:1 - Rear diff is 3.54:1

Acceleration is no different at all on either box untill you get into 5th and 6th where the UK is slower due to taller gears.

 

i did actually realise that it is the drop gear that makes the difference not the diff but the overall effect of dropping the final drive ratio from the gear selected by .36 will affect acceleration,although the box final drives are the same the drop gear alters the uk box to give a longer final drive meaning at certain engine speeds one car is pulling a higher top speed than another though the other will accelerate quicker.
cheers steve

 

up

 

steve, sorry but you are completley wrong there. The only difference the drop gear makes is torque transfer by all accounts.

The rear diff is 3.54 on a uk, but when multiplied by the drop gear of 1.1 it becomes 3.9, which matches the front diff.

Having had both a JDM and UK 6 speed in my classic on the same engine, i can assure you, the only difference is in 5th and 6th, nothing else. 70mph in 4th on a JDM 6 speed will be the same revs as 70mph on a UK 6 speed.

Steven

 

i was under the impression that the drop gear affected the front diff not the rear diff ratio,to give longer gearing and better cruising speeds,otherwise why bother with introducing completely different rear diffs when all they had to do was fit alternative gear ratio's and keep the jap front center and rear diffs??

 

up