Currently have a 3.9 ratio torsen out of a 01 NB 6 speed that I plan on swapping into my 1990 with a 5 speed before the turbo build install. I will be aiming for around 200 whp once the build is complete. I’ve seen that lower ratios are better for higher power, anybody can chime in on the 3.9 torsen with those power levels? Or should I look for a 4.1 ratio torsen instead?

 

What's the purpose of your car? Mostly street, or track use?

For a street turbo car 3.9 + 5 speed would be nice, with longer legs for cruising on the hwy vs a 4.1. I'd run it and see how you like it, though with only 200WHP it might be a bit sluggish. For track use it won't be optimal though.

 

Im planning on street with occasional track use maybe 1-2 a season. It’s mostly a DD build with some pep to it.

 

For that use it’s probably going to be pretty decent. I’d say try it before going to the trouble of swapping it for a 4.1.