Autocrossing and lapping with a 2 way: who's done it?

[Crazyced]

I drove my new bone stock 1990 240sx for the 1st time at my very 1st autocross last weekend and had a blast. Actually took top 3 in my class!

2 things I now feel I would gain from upgrading is coilovers and an LSD. As luck would have it I already have those parts laying around. :hsdance:

The downside is that the JDM spare diff I have has a KAAZ 2-way in it. I did my research and a lot of people say go with a 1.5-way, 2-way is just for drifting, etc. But some of them who actually ran a 2-way in grip situation actually don't mind it, some love it and say you can fairly easily drive around the downsides.

Now, what I have is a 2-way, that's just the way it is and I don't want to go trough the trouble of selling it and trying to find a 1.5 way and possibly have to install in in a pumpkin.

So I'd like some more feedback of people who are actually rocking a 2-way diff in a grip context, how you like it and how you drive around its possible shortcomings.

Thanks!

[racepar1]

Kaaz 2 way is super aggressive, it'll be clumsy for your application. I had one in my car shortly, it was just stupid unpredictable understeer. You could literally feel the diff locking and un-locking as you entered the corner. I also ran one of the old Nismo 2-way diffs and it was much better, I think the Kaaz would have been better with better fluid as well. When I put the open diff back in the car I LOVED it in comparison. The car was just so free into the corner, rotated nicely. I honestly think that a 1-way might be the way to go as long as you don't mind the car being a little free on corner entry. All you can do is try it and go from there, but I wouldn't reccomend it...

[Crazyced]

Kaaz 2 way is super aggressive, it'll be clumsy for your application. I had one in my car shortly, it was just stupid unpredictable understeer. You could literally feel the diff locking and un-locking as you entered the corner. I also ran one of the old Nismo 2-way diffs and it was much better, I think the Kaaz would have been better with better fluid as well. When I put the open diff back in the car I LOVED it in comparison. The car was just so free into the corner, rotated nicely. I honestly think that a 1-way might be the way to go as long as you don't mind the car being a little free on corner entry. All you can do is try it and go from there, but I wouldn't reccomend it...Mine is one of the older version with 8 plates instead of 16, plus it's not new so it might not lock as hard on entry. Like you said, I'll try and see. But open diff felt like my brand new clutch was slipping hard on every hairpin. Car was going nowhere fast.

[racepar1]

If you are going to run the 2 way I would reccomend a large rear sway bar. It will help the car rotate into the corner...

[Crazyced]

If you are going to run the 2 way I would reccomend a large rear sway bar. It will help the car rotate into the corner...I do have a godspeed 28mm bar laying around.

[Wookie384]

Another thing to take into consideration is your driving style, the overall set up on the car and even your alignment. I've known Racepar1 for a long time and he is a pretty aggressive driver in terms of corner entry and speed, his line is nice and clean, on the other hand I'm not as aggressive so his diff and sway-bar settings would not be a perfect fit for me. Since you have the parts handy just throw them on and see what you think, and adjust from there.

[Teambadrun]

You may be better off getting a 1way, 2 way is fine for racing type applications but it can create allot of oversteer and if you have grippy tires it can great allot of understeer.

[Thmotorsports]

You may be better off getting a 1way, 2 way is fine for racing type applications but it can create allot of oversteer and if you have grippy tires it can great allot of understeer.

Wow, thread revival. Lol.

But this thread covered it pretty well.

2-ways can definitely introduce some off throttle push. Adjusting ramp angles and lock can help some. And you can really fine tune the characteristics by changing these things.

[Speed Junkie]

Kaaz 2 way is super aggressive, it'll be clumsy for your application. I had one in my car shortly, it was just stupid unpredictable understeer. You could literally feel the diff locking and un-locking as you entered the corner. I also ran one of the old Nismo 2-way diffs and it was much better, I think the Kaaz would have been better with better fluid as well. When I put the open diff back in the car I LOVED it in comparison. The car was just so free into the corner, rotated nicely. I honestly think that a 1-way might be the way to go as long as you don't mind the car being a little free on corner entry. All you can do is try it and go from there, but I wouldn't reccomend it...

Another thing to take into consideration is your driving style, the overall set up on the car and even your alignment. I've known Racepar1 for a long time and he is a pretty aggressive driver in terms of corner entry and speed, his line is nice and clean, on the other hand I'm not as aggressive so his diff and sway-bar settings would not be a perfect fit for me. Since you have the parts handy just throw them on and see what you think, and adjust from there.


I had a Tomei 2-way in my miata and now have a kaaz 2-way in my S13. I definitely didn't feel it locking and unlocking in decel during hard driving but it definitely makes the car less versatile in driving styles. In the miata for example, in a tight autocross, if you weren't entering the corners properly committed with the weight on the front it would tend to understeer slightly.

Changing the suspension setup (usually just alignment) to a more oversteer-prone setup will get rid of the majority of understeer. You're supposed to do this anyways when changing something as sensitive to handling as the diff.

I also added Ford friction modifier to my 240 diff which is like twice the size of the miata 1.6 diff lol. I think with fewer discs (or rearranged discs) and some friction modifier that would give you a good compromise.

Despite the shortcomings (noisy during normal driving, requiring more maintenance, ideal for a narrow category of driving) of any performance part, ANY proper LSD will far outperform an open diff in a performance driving environment. A 2 way might not be as good as a 1.5 way for performance driving but it will be far better than an open diff.