R34 Gtt - Series 2 Torsen Diff Centre Into Series 1?

[gwilkinson34]

Does anyone know if this is possible? I have also heard the s15 torsen diff centres are a straight swap into the R34, but is this still the case between the viscous and torsen centres?

Hoping the torsen diff might cure some of my traction woes...

[GTSBoy]

It's doable. I have S15 helical centre with R34 4.11 gears in R32 housing. This stuff is so mix and match that you can do almost anything. The only problem for me, apart from the larger amount of money it ended up costing to put it all together, is that the half shafts for the helical centres are different than the viscous centres. I only had 3x2 bolt half shafts for mine so ended up having to use Silvia driveshafts in my R32. A bit homo, but better than a viscous diff by a factor of a trillion.

In your case, just buy a complete diff and swap the whole lot. Why faff abaout with swapping centres? ABS sensors are the same, yeah?

[gwilkinson34]

Yeah - sussed out with a tuner that it would be more of a pain in the arse to swap the centres than just get a new diff. Now comes the question - what to get?

It's been suggested that I go with a Nismo 2 way, although the car is pretty much 100% a daily driver, so I don't want it to be a complete hassle to drive on the street. Would I be better off with a 1.5 way? My main concern is straight line traction...

[GTSBoy]

2 way really is a track diff. It will have significant LSD action even on overrun, which tends to cause understeer into corners. On a track you will put up with that and adjust driving style to suit in order to get the consistent behaviour out of the diff. On the street, not so much. 1.5 way still has some trailling LSD action but is less cranky and will be easier to turn in etc. For a close to 100% street car, I would choose 1.5 over 2 way, but there are plenty of people around here who will argue that 2 way is the duck's nuts on the street. It's just a case of what you're willing to put up with.

If straight line traction is your main concern, then a 1 way Nismo would do the job on the street.

When I said "just buy a complete diff and swap" I meant buy a complete GTT helical diff and put that in. Assuming you can find one. They're like rocking horse shit. Which is why I did mine with an S15 centre.

FWIW, for a street car I would still choose a helical diff over any of the mechanical options. The drive is really positive. Sure they have a few little issues like zero drive if you get a wheel up, but that is seldom going to be a killer unless you routinely have to use an unpleasant driveway or like to drive with one wheel on ice.

[gwilkinson34]

You make some good points - unfortunately they have just confused me even more, as the guys that built my engine seem certain that a 2 way is the best option. However, as the car is basically only going to see the street, with a few runs down the strip, it seems like overkill.

What options would there be for a replacement helical, or would it entail getting an S15 centre, new half shafts etc and putting something custom together?

[GTSBoy]

The helical centre in an S15 is the same centre that was used in the R34s (those that had them, anyway). The only difference is the gears that are bolted on and the half shafts. So the easiest swap for you is to obtain an R34 helical diff and just drop it in. Job done, wipe hands, drive away. The only hassle is tracking one down, as there aren't many of them.

The next way to get a Nissan helical into it is to obtain an S15 diff and strip it and yours apart and swap the centre into yours. You need a diff specialist to make sure it's set up right. That cost me a few hundred on top of the diffs I bought. You'd then need some Silvia driveshafts as well. Not as easy, and a lot more expensive than using an R34 helical. A little easier to find the diffs though.

There are third party helicals available, but there is significant cost associated with these and I'd suggest you'd get better value for money with a mech diff.