I am very happy with the result of my UT engine build. It works well on track and with X1/9 5 speed gear box/gear ratios I can keep it within maximum torque range 4-7000 rpm in most situatons. However, this is mainly a street car so I am looking for making the final drive taller, more like standard UT 3.588:1 instead of X1/9's 4.077:1.
I also have an UT Mk2 gear box but it doesn't fit the UT Mk1 (or X1/9) engine. -The input shaft/splines differs.
I have an idea to move the final drive from the UT box to the X box. But does the pinion and crown wheel from the UT Mk2 box fit in the X box? I also read in the forum that pinion/crown wheel from Ritmo/Strada/Regata would work? But they have the same ratio as X? I've been searching the web for Final Ratio Gear Kits, but all I've found are shorter than stock 4.077:1, most likely best for tuned, high revving X1/9's and hill climb.
I am also thinking about having a Torsen diff made for VAZ Samara. But that will require some modifications a described at
https://www.villevieri.com/egbox.htm .Has this been done by any member in the forum?
Any feedback would be appreciated.
EDIT: Forgot to add the UT/X ratio comparison sheet that may be of interest:
View attachment 37512