87 turbo 5spd rear end questions
 

Hey guys,

Pretty new to Supras, only know what I read in the past, and I haven't retained much. SO questions :-)

- I read they have 3.90 gears in them, which is ok, is that standard for a 5spd Turbo or did they have other ratios they ofered?

- Independent LSD how much HP can you put to that, I'm guessing this one has close to 400HP.

- With 400 HP and the Independent rear suspension can I run a ET Street tire on that without worry about breaking shalfts?

- Anyone install other rears? 9" rear, 8.8 rear or something?

- What size ET street fit well if you recommend using them.

The diff varied by model and year. The non turbos had a 4.30:1 for all years. The non-US market 1JZ equipped vehicles had a 4.10:1 torsion available but it won't hold much past 450RWHP.... depends on the driver... it's not a popular swap as the regular LSD is much more robust and available. The US Turbo models had a 3.93:1 until '89. '89 and newer had a 3.73:1.

The stock LSD is VERY robust and will take a lot more than 400HP at the wheels... especially if rebuilt. The axles are also no problem as long as age hasn't taken it's toll on them.

Some people have swapped in different (domestic) units but under 500-600 RWHP there's not much point (they've been shown to be reliable beyond that level). Some people have had the stock unit crash on them at lower power levels but age is more likely to blame than frailty as a number of people have really put them to the test in high power applications with no problem.

http://www.toysport.com/technical%20...ifications.htm

axle code is on the plate under the hood on the firewall

I believe 86.5 - 92 with automatic transmission for both engines has a 3.91 differential.

The 3.91 was used in turbo models (regardless of whether they were M/T or A/T) from '87 through the '89 model year (ALL N/A's have the 4.30); Thereafter it was 3.73. But do as bio said and look at the code on your firewall data tag to see what your car came with from the factory.

+1 bioskyline, very nice link. :D

yey me! i learned how to read the tag looking for 4x4 toy axles. you can even tell what gear set they are by the paint on the pinion nut. but i dont have that list handy