Hi everyone,

I recently switched from the 4:1 Torsen 1 over to a Torsen 2 for its shorter 4:3 ratio.

In doing my research (correct me if Im wrong), I found that the Torsen 1 has stronger lockup characteristics all around than the Torsen 2, with a bias during acceleration. On the other hand, the Torsen 2 has a lock-up bias during deceleration.

From a drivers standpoint - what does this mean? In my head, it seems like apart from the longer ratio, the torsen 1 would be better suited for performance due to a stronger lockup as well as a bias under throttle. I immediately think of a situation where you are mid/late corner, and by giving it throttle early, the torsen will allow you to exit a corner at a higher speed than you would without a torsen.

On the other hand, with a torsen 2, would it be better suited towards a higher corner entry speed with heavy trailbreaking? Or would its lockup characteristics still be strong enough to drive the same way upon corner exit, regardless of its bias?

Granted, I understand that Im probably not one of the fastest drivers out there, but it would be interesting to finally clarify the differences between the two for future purposes. After all, regardless of the differences, it all comes down to how they apply to our driving.

 

This is probably wrong, but I'll throw in a thought. The stronger lock-up on acceleration might also cause a bit of additional understeer on corner exit, since the wheels going the same speed will try to keep the car in a straight line.

This is an interesting topic, I'd love to hear what someone who actually knows what they're talking about thinks on it.

 

And with that same logic:

the type-ii can induce understeer at corner entry.


rule of thumb:
Type-ii for street driving, type-i for performance driving (autox, track)

 

Thats the logic that I pretty much figured..

But doesn't the Type-2 come on the newer cars like the S2000 and BRZ/FRS? Also, by that same logic, why does it seem like the Type-2 is more appealing to performance drivers when really, if it was for the shorter ratio, wouldn't simply swapping in a T-1 into a 4:3 open diff be the better thing to do?

 

It's good to have this discussion; however, a Type 1 versus Type 2 (versus Type 3 versus Super Fuji) isn't going to be the reason why you're 5 seconds off of SM pace. Usually when you start going into the minutiae into the various diffs that came with the car, the answer of "**** it, put in an OS Giken" is usually the answer.

 

I absolutely agree, which is actually the reason why I started this post.

I think that by knowing the differences in lockup characteristics between a T1 and T2 and how that applies to cornering, it would be extremely useful in helping a driver consciously adapt their driving style if they ever make a switch. That's exactly what happened in my case. I just swapped out a 4:1 T1 from a 95 to a 4:3 T2 from a 99.

 

please stop saying lockup or I'll get all pedantic on your ***

 

It's more appealing to the car manufacturers that wants to buy a cheaper LSD. the T2 is cheaper to manufacture than the T1, also a bit stronger. The T2 really seems, after reading their site, more suited for FWD applications.

no one here really wants the 4.3 rear, everyone wants at least the 4.10 and in a lot of cases the 3.63.

 

My apologies, thats the term that I've constantly seen being used. But without you at least stating what the proper term is, I wouldn't know what other word to use.

 

There is no term because that kind of behavior doesn't exist with Torsen diffs.

They don't lock up (i.e. connect both axles solidly.) That's a concept that involves rotational speed.

They do have a maximum torque bias, which means that the maximum torque delivered to either axle depends on the torque being delivered to the other axle. This is a concept that involves torque and is independent of speed. If, for example, the torque bias ratio is 2.5 and the passenger side axle can deliver only 100 ft.lb of torque (due to limited traction) then the driver side axle will never get more than 250 ft.lb of torque no matter how much is available through the drive shaft.

Open diffs have a torque bias ratio of 1. Torsens don't lock up any more than open diffs do, they just have a higher maximum torque bias ratio.

While I'm ranting, I have to admit that I don't understand how any Torsen, type 1 or type 2, could possibly tell the difference between accel and decel. Well, maybe a type 2 could be designed to, but why would it? And why would it be designed to have a higher bias ratio on deceleration than acceleration? Seems backwards, but I'm really just guessing here. Maybe someone can explain if I'm missing something.

 

I know of at least 3 people who want the 4.3 rear: the OP, Savington, and me.

 

And me. Anyone local is welcome to straight trade my 4.1 for their 4.3.

 

Have 4.875 with 5sp, want 4.44 and 6sp ...
4.44 with OSG and narrow ratio dog 6sp would not hurt at all

 

dual post

 

LOL.

Get a Torsen. Get the one with the gear ratio that's better for you. A pro might be able to tell the difference between identically-geared Type 1 vs. Type 2 Torsens. You won't.

And BTW, I hope you get your foot back on the throttle WAY before mid-corner. Maybe even left foot brake.

 

The T1 has a bit more of the torsen push, and does a bit more of the torsen kick on quick lifts. 98% of people wont know which one is the car after driving it. The T2 is supposed to be stronger though.

 

Well, I'll be damned. You just described one of the differences in driving feel between my Silver car (with T1) and my Red car (with T2). There are so many other differences between the cars that I never considered the type of Torsen might be part of it.

 

The discussion is still very relevant even if that is the answer because the OSG is available in a 1 way, 1.5 way, and 2 way configuration.

 

I guess, but its not in the race prep section so I dont think its a track guy. The torsen is a better choice for auto-x for us in the 99%'s who cant afford to have 3-4 setup diffs ready to drop in the car and/or are too lazy to pull the diff and change the setup based on the surface and if its raining.

 

I have never actually driven a 4.1 torsen ,but I love my t2 in my SSM 1.6 sc car. It beats the hell out of blowing up VLSDs We also have a t2 in the CSP car that I drive and it, I like it more for the acceleration (just looking at the other CSP cars that have T1s)