SC400 differential gearing change...

[jibbby]

It has recently been brought to my attention that the Nissan (R200) differential gearing which is found on the Nissan 300ZX TT's are interchangeable with the Lexus/Soarer/Supra TT Automatic...This swap would make for faster times and a lower gearing change...Can anyone shed more light onto this differential gearing swap? I have searched for information on this swap and found nothing... I am looking for proven swap applications, results after the swap, exact bolt on exchanges, what this swap will do to your top speed, etc...Any info onto this would be most appreciated....I have been looking for a lower differential gearing change for my Supra TT LSD for years and have always came up blank until now...ANYONE?

 

[WDoherty]

jibby, don't know anything about the nissan diff, but i believe their were na auto or 5 speed supra's with lsd's with a low ratio,like 4.27 or something. maybe look on intellexual.net about that.

 

[jibbby]

Already know about those...Thanks WD...Looking for more info on the Nissan gearing changes...Results after the change...

 

[JBrady]

It has recently been brought to my attention that the Nissan (R200) differential gearing which is found on the Nissan 300ZX TT's are interchangeable with the Lexus/Soarer/Supra TT Automatic...This swap would make for faster times and a lower gearing change...Can anyone shed more light onto this differential gearing swap? I have searched for information on this swap and found nothing... I am looking for proven swap applications, results after the swap, exact bolt on exchanges, what this swap will do to your top speed, etc...Any info onto this would be most appreciated....I have been looking for a lower differential gearing change for my Supra TT LSD for years and have always came up blank until now...ANYONE?

Let me say that it is EXTREMELY unlikely that a Nissan part could/would/might/maybe fit a Toyota. The entire differential certainly would NOT be a direct bolt in.

Could the gears bolt on to the Toyota carrier? Also extremely unlikely.

Could you install a Nissan diff in a Toyota? Sure, cutting and welding and fabricating.

Why consider this when Toyota has a range of gears and limited slip clutch and torsen carrier of which you say you already have with the 3.769 ratio of the Supra TT automatic.

What ratio do you want and why?

With more torque it can make sense to actually go lower. The stock Supra TT 6spd ratio is 3.13. I THINK you could probably bolt in the gearset from an early SC300 (4.27) to your existing carrier. Some early Supras had the 4.27 with an optional LSD and the ring gear is the same size as yours is now.
http://mkiv.com/specifications/ncf/ncf93/ncf156.jpg

Changing the ratio makes for more torque at the wheels in each gear BUT it also causes the car to shift sooner and therefore be in a higher gear at a lower speed than before. This ends of offsetting the gains and there is not a clear improvement for any given combination. The stock gearset of 3.91 on the SC400s is a good overall ratio and your slight change to 3.769 is not going to make much difference. A change to 4.27s will feel stronger in any given gear but actual performance may not measurably change. With your TC and other mods and planned mods I do not see the worth of this effort.

Good luck.

 

[WDoherty]

well stated..........

 

[jibbby]

Hey, what can I say...Well stated JB.......I pretty much have traction problems now in 1st and 2nd so the gearing change would do me no good as you state...I have thought about that before this post, but also thought maybe third gear would come to life..That is why inquired about results of gearing changes.....Just venturing and inquiring into the possibilities and benefits to a gearing change that is all...