Diff Mount to fit 350Z R200 Short Nose in 75 280Z?

[HusseinHolland]

I read in the pinned V6 conversion thread that  "You'd have to use a Ron Tyler (RT) type mount to install a short nosed R200." 

 

Not having much success searching for any examples where anyone has actually done this. 

 

I'd like to use the LSD R200 from my '06 350Z parts car as part of the drivetrain conversion.

 

I emailed  TenchoVersions about the one they list https://www.technoversions.com/DiffMount.html

 

TIA

Edited November 22, 2023 by HusseinHolland

[NewZed]

The RTz mount is for the long-nose.  Great design, works really well.  But it's too far forward for the short nose.

 

There are/were several short nose mount designs out there but none are really striking as far as functionality.  The front of the short nose is just in a bad spot.  Empty space up to the thin sheet metal above it.

 

An example, looks like what ArizonaZcar used to offer.  Maybe they still do.  Uses the control arm tubes as mounting points -

 

https://technotoytuning.com/nissan/240z/z-power-cradle-short-nose-r200r230-and-ford-88

 

Many of the short nose options have been discontinued. Many of the early designs had problems.  Too much leverage.

 

p.s. I'm on CZCC too.  Zed Head.

 

 

 

 

[calZ]

This was always my favorite design, but it's something you'd have to make custom. 

[rturbo 930]

I think I'd just stick with the stock diff and put an LSD in it. It's already installed, ie, no retrofitting needed, and the 350Z diff is a viscous diff, which isn't exactly ideal. On top of the mounts, you'd also need to work out adapting the axles, and I don't know if there's a product out there to handle that, but if not, that could be pretty costly. Seems like a lot of work for not much benefit.  

[HusseinHolland]

On 11/22/2023 at 10:37 PM, NewZed said:

 

p.s. I'm on CZCC too.  Zed Head.

 

21 hours ago, calZ said:

This was always my favorite design, but it's something you'd have to make custom. 

 

 

Many thanks for the link & pic. It is most helpful to see how others have tried to resolve it. The home made version looks very practical in terms of containing the diff's desire to arc upward under load. The TechnoToy design looks like it would be easier to create, but no counter hold from above.

19 hours ago, rturbo 930 said:

I think I'd just stick with the stock diff and put an LSD in it. It's already installed, ie, no retrofitting needed, and the 350Z diff is a viscous diff, which isn't exactly ideal. On top of the mounts, you'd also need to work out adapting the axles, and I don't know if there's a product out there to handle that, but if not, that could be pretty costly. Seems like a lot of work for not much benefit.  

 

The problem is my diff has 250K on it, and the gear whine is pretty bad. I don't see the point in putting an LSD in it. I did also search months ago for a LSD that would work in the long nose - I don't recall finding a clear solution for that. Is there a specific LSD that you recommend? I haven't looked into new ring & pinion options.

 

Since I already have the 350Z diff, and I'm not planning on going much over stock HP, I didn't see the viscous design being much of a concern. As an aside, Volvo used a viscous clutch setup in their early AWD's, and that actually held more than 2x stock HP in practice. Is there a known flaw with the Nissan LSD design?

[NewZed]

The viscous diffs apparently have a very slight hesitation before they grab.  It's a racing consideration.  

 

Don't forget that your 75 has a unique bolt pattern and size at the diff flange.  In case you find a different long-nose R200 to swap in.

 

Mfactory has what looks like the simplest long-nose R200 LSD solution.  

 

[rturbo 930]

4 hours ago, HusseinHolland said:

 

 

Many thanks for the link & pic. It is most helpful to see how others have tried to resolve it. The home made version looks very practical in terms of containing the diff's desire to arc upward under load. The TechnoToy design looks like it would be easier to create, but no counter hold from above.

 

The problem is my diff has 250K on it, and the gear whine is pretty bad. I don't see the point in putting an LSD in it. I did also search months ago for a LSD that would work in the long nose - I don't recall finding a clear solution for that. Is there a specific LSD that you recommend? I haven't looked into new ring & pinion options.

 

Since I already have the 350Z diff, and I'm not planning on going much over stock HP, I didn't see the viscous design being much of a concern. As an aside, Volvo used a viscous clutch setup in their early AWD's, and that actually held more than 2x stock HP in practice. Is there a known flaw with the Nissan LSD design?

I'm not a diff expert, but if my diff was whining, my first thought would be to rebuild it. Diffs aren't really known for wearing out, but if it is, my second thought would be to just go get another. Yours is likely a 3.54 which should be easy to find for a reasonable price. 

 

As for the problem with viscous diffs, my understanding is that if used hard, as they would be on a track, they get hot, and just kinda stop working. And I could be wrong, but at that point I think you just have to replace the diff. I would only ever consider a CLSD or helical/torsen.

 

The MFactory helical LSD mentioned above would likely be a good choice. There is also the OS Giken Superlock is another option which is a clutch LSD, but also quite a bit more expensive. I know Quaife LSDs used to be available, looks like they still sell them for R200s, but not sure if they're for short nose or long nose. AFAIK you can put a long nose LSD into a short nose with some work. 

 

There is also the Subaru option. Pretty easy swap, should hold up fine if you're only going with stock VQ power, especially if you won't be launching or racing the car. They came in both CLSD and torsen, a 3.54 torsen should be pretty easy to find. This may actually be the easiest option of all. 

 

 

 

[HusseinHolland]

3 hours ago, rturbo 930 said:

I'm not a diff expert, but if my diff was whining, my first thought would be to rebuild it.

 

 

I think you missed what I said - mine has gear whine, not bearing noise. The only way to fix gear whine is to replace the worn ring & pinion. Once that wear pattern is established, you really can't 'adjust' it away. So, not much point considering a LSD for my existing diff. I do have the long nose diff. Since I have a good working LSD diff in the 350Z, to me it makes more sense to try to fit that, than to buy a used R200 long nose & rebuild that. I'm never racing this thing, so I don't see the VLSD being an issue in that regard. I will have to investigate the axle flange issue, since I would like to keep the speed sensors intact. 

[NewZed]

It's the propeller (driveshaft) and pinion shaft flange.  But, also, on the side axles, you'll need adapters for the 350Z diff.  Probably knew that.  The axles won't swap.

 

The R200's long noses are inherently noisy.  Just rough and sloppy ring and pinion cuts.  Many people hear gear noise when their diff mounts wear out, front and/or mustache bar.  Clunking during shifting is also a sign of worn mounts.

 

 

[rturbo 930]

49 minutes ago, HusseinHolland said:

 

I think you missed what I said - mine has gear whine, not bearing noise. The only way to fix gear whine is to replace the worn ring & pinion. Once that wear pattern is established, you really can't 'adjust' it away. So, not much point considering a LSD for my existing diff. I do have the long nose diff. Since I have a good working LSD diff in the 350Z, to me it makes more sense to try to fit that, than to buy a used R200 long nose & rebuild that. I'm never racing this thing, so I don't see the VLSD being an issue in that regard. I will have to investigate the axle flange issue, since I would like to keep the speed sensors intact. 

No, I read that, just like I said, not a diff expert lol. Never gotten into one, or needed to. Thanks for confirming what I suspected, that a whining diff needs a new gearset.

 

I get that you want to use what you already have but I don't know if that's necessarily the best solution. In your situation, Subaru R180 would be my choice. 

[HusseinHolland]

Thank you both for your input.

 

I did not know these diffs were known to be noisy. In my case, it's not due to worn suspension or the diff mounts, as all that I have replaced since I got the car. The noise is much the same as it was with all worn out stuff, just no clunks any more, in that regards.

 

 

[HusseinHolland]

On 11/24/2023 at 12:34 PM, NewZed said:

The viscous diffs apparently have a very slight hesitation before they grab.  It's a racing consideration.  

 

Don't forget that your 75 has a unique bolt pattern and size at the diff flange.  In case you find a different long-nose R200 to swap in.

 

Mfactory has what looks like the simplest long-nose R200 LSD solution. 

 

Thanks NewZed / Zed Head

I think if indeed my ring & pinion only has normal wear pattern, the MFactory diff would be my preferred choice. I took a look around at Subaru R180 installs, and that alone requires a bunch of additional parts to make it fit, according to the threads on it . I already have an MFactory LSD & Ring & Pinion setup in my JDM Honda drivetrain (in My Fiat X1/9), so I'm familiar with the quality of their parts.

Edited November 26, 2023 by HusseinHolland