'83 Turbo Borg Warner with R200 3.9 ?

[12doplumbing]

My 15 year olds '72 build has come to a crossroads; we bought a T5 Borg Warner thinking it was from a non-turbo 280zx. We have a 3.9 gear ratio in our R200 and are getting ready to drop in a turbo engine. We have read the threads regarding the best match up for a turbo L6 is the 5 speed from an 81-83 non turbo 280 along with a 3.9 ratio r200.

We started our "double checking" of driveline components in prep for a driveline search when my son found the numbers on the Borg Warner transmission tell us it was made for a 1983 turbo 280. This had my son reread the many threads regarding configuring a 3.9 with this 5 speed and turbo -- he and I both understand that this will cause first and second gear to be really short; an annoyance he really doesn't want to keep investing in.

Any feedback regarding this interpretation? Any remedies short of another 5 speed? And if we need another 5 speed (one from a non turbo 81-83) is it a "Borg Warner"? Or a "T5" at all?

Appreciate help here. We don't want the reverting to a 3.54 r200 solution....

[NewZed]

The 240Z's came with a 3.592 first and 3.36 rears (12.07).  The 280Z's were 3.321 with a 3.54 (11.75).  The NA ZX's were 3.062 with a 3.9 (11.94). 

 

You'll be at 13.65 (3.5 x 3.9).  Lowest first gear ever.  Swap to the diff you don't want to hear about and you'll be at 12.93, still lower than any factory setup.  There's always big tires.  

 

Edit - just realized that the 3.54 combo won't be lower than any factory setup. just lower than any factory 240Z or 280Z setup. Using the 3.54 just gets to the factory 1983 Turbo 280ZX gearing,  Lower overall, probably to help with the ~500 lb weight increase (Wikipedia weights), from a stop.

Edited May 1, 2014 by NewZed

[madkaw]

I run 3.90 gears with my BW T-5 with an L24. Yes the first gears are low, but does it bother me -no. Because of the spread between 2nd and 3rd, 3rd gear makes for a great passing gear. But might be comparing apples to oranges an NA to a turbo motor.

I know I like the trans because of it's shifting smoothness.

Not sure why you think you are at a crossroads. Changing diffs is an easy process. 

Your bigger issue -if you haven't already considered this-is that trans needs a dedicated DS from the turbo car, which in turn has a dedicated flange for the Diff. So you might have more issues then you think.

[Six_Shooter]

I'm running a Turbo L28 in my 240Z.

 

Other specs:

-3.90 R20, sadly open diff

-'81 280ZX trans (non-turbo)

-CV shafts

-225/55/R16 tires 

 

First gear is almost useless, (when performing a drag launch) but the rest of the gears are decent for how I drive my car.

 

"Normal" driving the first gear is good, plenty of torque to get the car started off from a stop light without much effort.

 

As suggested you could swap to a different diff gear if you can't find a different trans.

 

AFAIK the T5 only came in the '83 Turbo (in an S130 chassis), N/A had the other trans (I don't recall the ID code off hand)

[yhlz]

Borg Warner only came on the last year turbo ZX if I remember correctly.

Edited April 29, 2014 by yhlz

[78zstyle]

It could be worse, you could have a 4.11 diff! 

[mattb3562]

I got a t5 out of an 82. Its paired with 3.55 final gearing and it pulls like crazy. Through all gears. (Still in 5th gear, I can roll on the throttle and build plenty of boost for passing without dropping gear.)