Nitro Front Diff LSD

https://www.nitro-gear.com/Toyota-T8S-8-Nitro-Helical-Limited-Slip-p/tors-t8s-3.htm

Has anyone used this yet? I read @BassAckwards plans to.
I know the 1st gen Ford Raptor has one in the front with part time 4WD like our trucks. Wondering what the torque bias may be, how it plays with our ADD and how the road/steering feel would be affected in 2WD

 

Subbed for feedback

 

Interestingly, they don’t list fitment for any AWD Toyotas that use the same 8” clamshell (ie, GX470, FJ Cruiser, V8 T4R) which leads me to believe that the bias ratio is pretty aggressive. I’ve emailed tech support twice but no reply yet. I just called and the guy on the phone had no answers...
May not be a good application for those that have the manual Xfer case and ADD delete

 

I emailed them asking about ratio compatibility and they said only 3.73 and down work. rules me out at until i go back to 3.73s way down the road. Still interested in hearing others’ feedback, but i think ill live with AWD and an open front diff for now

 

I can hardly believe that. By down maybe they don’t mean numerically but deeper gears. Otherwise it would rule me out too, just like most prospective customers.
I was getting at the torque transfer bias ratio. 1st gen Ford raptors have Similar part time 4WD and IFS with a Torsen and the bias ratio is mild at 2:1

 

Here's what they told me when i asked if it'd work with my 5.29s: "I know this would not be compatible it fits 373 and down numerical ratios or thick gears designed to fit the 373 carrier"

You might be right, or it might be warranty related

 

This should help you out....

https://www.tacomaworld.com/threads/8”-ifs-clamshell-w-frs-torsen.561017/

 

I've read, but have not confirmed, that the TBR is 4:1 for the FRS/86/BRZ diff.

 

After doing some more reading, sounds like it's compatible with aftermarket gears but they have to be thick cut but im not sure what ratios that would include. So that's good news after all

Here's some good info about the gears and carriers on Nitro's website for a package they offer for the tacos. Looks like maybe just 4.30s and 5.29s wouldnt be compatible

 

I followed that but it’s a different unit...?

That would be too much in my opinion. Too aggressive and you’ll feel that when turning

 

Virtually nobody has numerically lower gears than 3.73 in an 8” clamshell. I run 4.10 factory gears from a 4banger.

 

There is a carrier break for 3.73 and down, meaning lower gear ratio. If you have 4.10 gears from the factory you have a 3.90 carrier. Most others will have the 3.73 carrier. To swap aftermarket sets require thick cut gears to run 4.10, 4.56, or 4.88 in the 3.73 carrier, otherwise you can use the standard cut gears in the 3.90 and up carrier. It wouldn’t make sense they would design this for only a small population of trucks, they’ve designed it for trucks that came stock with 3.73 carrier and have thick cut gears or stock gear sets. It’s 3.73 and down, but the down is almost non existent I don’t know why anyone would go with taller gears than the 3.73 from the factory or if they’re even offered for that matter.

I would wonder what difference it would make if you had an ADD delete, I wouldn’t think any in 2wd since the difference in wheel speed wouldn’t be much unless on a really deep turn, but would be interesting to hear their feedback.

 

Yes, I swapped in the whole OEM 4.10 ratio open front and rear diffs from a 4 cylinder and added a Harrop e-locker in the rear. I’d go Detroit if I could do it over.
So it looks like this Nitro Torsen would work but I’d need their thick cut 4.10 gears too, which makes it too expensive, and makes the drilled out Scion rear Torsen from the thread @Jowett linked above much more appealing particularly because I could use my OEM gears.
That leaves the matter of torque bias ratios which I don’t know for either unit.
And yes, the 2wd turning radius is something I am not willing to increase so I’d want a TBR between 2 and 3

 

yes you’d need the 3.73 carrier and new thick cut 4.10 gears to keep your current ratio to be able to use the nitro limited slip setup. Fortunately there’s a lot of spare front diffs floating around so the carrier wouldn’t be too hard to source, heck I have a spare 3.73 front differential I’d let go for a cheap price as it’s just collecting dust.

But for overall simplicity of the swap, the Torsen from the scion makes the most sense for you id think, assuming the TBR is within the specs you’re hoping for. I don’t know where to find the TBR but maybe it’s buried in a Toyota document somewhere?

 

The Nitro Torsen unit is the carrier. The whole swapping crown/ring gear carriers only applies to folks who just want to regear but not add a traction device.

if I could get my hands on one of these Torsen units I could figure out the TBR by disassembly because it’s built into the worm gears

 

ah ok, for some reason I was thinking it was installed in part of the oem carrier assembly. That makes more sense.

 

Now that I think about it, the ADD front diff system would probably not play well with a Torsen. Or more appropriately put, having one side of the Torsen driven will not make for a happy long lived unit.

 

with one side being always "open" there will be constant friction created in the front differential, not sure if constantly being open in 2WD with the ADD system unlocked would create too much heat and cause any long term degradation or premature wear/breakdown of bearings and differential oil.

https://torsen.com/category/tech-info/

 

Well that is exactly the application this subject unit is designed for.

I just realized you and @Jeff Lange are not the same person, lol. Same avatar had me fooled.

btw, I got a call back from someone at Nitro Gear today who told me that the TBR is the same as the true trac which is listed at 3.5.

 

I guess we are just twins , I’m Michael Richards, I’m assuming that’s Jeff’s real name.