R200 diff from Fuga/M45 and upgrading to LSD

Forum for Infiniti M35 and M45, and Nissan Fuga owners.
Nelson Sandalwood
Posts: 10
Joined: Sun Mar 31, 2019 11:27 am
Car: M45

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Hi, I tried searching but the search keeps telling me it is too busy to search at the moment.

I am looking to change gear ratio and install an LSD into a R200 from a JDM Fuga 450 (m45 in USA). I have partially dismantled the diff and pulled the output shafts, they are 31 splines, and 33mm diameter. The stubs appear to be the same length but I have only eyeballed them and not measured.

The diff is from an auto, and I have read there are some differences fitting a manual and auto diff center, and that the ring gear offset is different for some unknown reason, I got that info from here: https://www.z1motorsports.com/transmiss ... -4523.html where they tell someone the rings will only work with a manula differential, I assume they mean the manual internals and that the diff housing (pumpkin) is the same for both manual and auto

Z1 say they can't help find the right pars, but will happily supply them once I have done my homework, which kind of sucks but that is what it is.

So I am looking for info, if I buy OEM ring and pinion, and an non-oem LSD will it all work out? The shafts appear to be the same as used in the GTR's, so I think a GTR diff like this will work https://shop.quaife.co.uk/nissan-skylin ... fferential based on the data sheet ( https://shop.quaife.co.uk/media/blfa_files/QDF14L.PDF ) it has 33mm shafts and 31 splines.

I would like to be more sure it will all fit before I buy parts and ship them to the southern hemisphere. Does anyone have any better source of information I can check out?

Thanks,


EniGmA1987
Posts: 2257
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 Infiniti M35 Sport

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I bet you can buy a used manual R200 diff on Ebay for around $200. Then you can change the gear ratio to what you want. G35, 350Z, M35, and M45 all use the same R200 differentials. Even some earlier model G37 and 370Z's use the same diff as us. If you plan to also put a helical diff in it then it doesnt matter if the used one you buy even has a couple hundred thousand miles on it since you would be changing everything but the outer housing anyway.
Note that with a manual model you will need to either replace the input flange, or modify your driveshaft flange to bolt to the manual diff. Also be aware that your axles and the spline count are different from the ones that are used on the G35, M35, etc, etc etc. You may have to replace your axles too depending on what stub shafts you are using and what diff you end up doing this project with. A user named "Ken in AZ" was the first to do rear differential work and he had an M45. I eventually bought that diff from him to put in my M35. He was telling me that he had to buy different axles and we verified my axles before we did the swap. The M35 axles were perfect for the diff already, where the M45 ones needed to be changed out.

Nelson Sandalwood
Posts: 10
Joined: Sun Mar 31, 2019 11:27 am
Car: M45

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EniGmA1987 wrote:
Mon Apr 01, 2019 12:10 pm
I bet you can buy a used manual R200 diff on Ebay for around $200. Then you can change the gear ratio to what you want. G35, 350Z, M35, and M45 all use the same R200
Hi, yeah, I don't want to go replacing all the axles and so in, the G's and Z's use smaller diameter output shafts and 5 bolts instead of 6, I would rather stay with 33mm output flange than to down size. The diff I am dismantling is an R200 but from an auto Fuga 450, so it should bolt to right into the car, I just want to replace the ring and pinion, and go to LSD from open.

The Quaif LSD unit I am looking at is a helical gear design. The dimensions all seem like it will fit, but I am worried about the 0.4" offset difference mentioned between auto and manual. Does anyone know where or what this difference is?

Z1 motorsport say on their web page ( https://www.z1motorsports.com/transmiss ... -4523.html ) the following to some other peoples questions.
  • Question: Will this upgrade need the limited slip differential replacement also or the gear change itself will work with the stock of my 2005 automatic 350 Z

    Response: You will need a "Manual" Differential. The automatic and manual versions are offset differently. If you try to install these gears onto an "Auto" diff it will never work.
  • Question: Hi, i would like to know if these gears are compatible with AT Differential Carriers, 2010. Thanks Rej

    Response: The LSD/carrier has a .4" difference in offset. You can use the cast iron housing but you will need a "manual" LSD. Depending on vehicle we may also need to confirm the companion flange style? 3 bolt Quibo coupling or 4 bolt companion flange?
But it seems they have given up answering questions, I have tried a couple of times over the last 3 or 4 weeks, they finally responded telling me I needed to find out myself and just let them know the part numbers I wanted, so I will, but I will let some other outfit know the part numbers I want, Z1 won't be getting a cent from me :)

EniGmA1987
Posts: 2257
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 Infiniti M35 Sport

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If the difference is the actual differential unit itself then the new Quaife LSD *should* work, but you will need to go with different stub shafts. I know the manual diff I have uses different length shafts.
Specialty-Z sells the same diff's and is a little bit cheaper than Z1.

EniGmA1987
Posts: 2257
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 Infiniti M35 Sport

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I did talk with Sebastian when confirming everything is ready for my appointment this Friday down there that the Quaife helical diff does use the different length stub axles (one is an inch or inch and a half shorter than the other). So if you do fit it within the same housing as your automatic diff, you must replace at least one of the stub axles too. And if you replace those, you must also replace your main axles to get the same mounting flange.

Primo13
Posts: 2
Joined: Mon Jul 02, 2018 4:53 pm
Car: 08' M35X

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Off subject (somewhat)-- and this being my first post on the forums; but does anyone know if the G37s DIff could integrate with an M35x?
I tried searching upon the forum, but ended up empty-handed.
Thanks!

Nelson Sandalwood
Posts: 10
Joined: Sun Mar 31, 2019 11:27 am
Car: M45

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Primo13, probably not, the M35x is AWD model so you need the same diff ratio front and rear.

Nelson Sandalwood
Posts: 10
Joined: Sun Mar 31, 2019 11:27 am
Car: M45

Post

EniGmA1987 wrote:
Wed Apr 03, 2019 7:20 am
So if you do fit it within the same housing as your automatic diff, you must replace at least one of the stub axles too. And if you replace those, you must also replace your main axles to get the same mounting flange.
I have read of people shortening one of the stub axles, so that might be the go. I don't like the idea of losing 4mm of the diameter of the shafts and dropping from 6 to 5 bolts, it seems like it would be weaker. I guess I need to find a shop and talk to them, but not much in the way of performance shops around where I live

What are you getting done to yours on friday?

EniGmA1987
Posts: 2257
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 Infiniti M35 Sport

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Primo13 wrote:
Wed Apr 03, 2019 8:45 am
Off subject (somewhat)-- and this being my first post on the forums; but does anyone know if the G37s DIff could integrate with an M35x?
I tried searching upon the forum, but ended up empty-handed.
Thanks!
As Nelson said.
However there is a G37X, so I bet those could mount up. I just havent looked into them at all, and it may be that the G37X ones are already the exact ones you have.




Nelson Sandalwood wrote:
Wed Apr 03, 2019 9:20 am
What are you getting done to yours on friday?
Engine and turbo coming out. Need to get back to a more reliable setup for a while as I go back to just 1 car, and will probably do a teardown of the engine again and see what is needed to be done to give it some better reliability. It was built as a race engine by another member here, and while it is really powerful, race engines werent really designed to last more than a season or two. lol. I have been using it as my weekend car the past couple years but it already had to replace something with the pistons last year. At this point I will probably put it back in the car in a couple years again, but maybe not if I get a good offer on the setup. Hard to sell 10K worth of engine and turbokit though, so ill probably just end up keeping it to put back in later down the road.

Nelson Sandalwood
Posts: 10
Joined: Sun Mar 31, 2019 11:27 am
Car: M45

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EniGmA1987 wrote:
Wed Apr 03, 2019 9:30 am

Engine and turbo coming out.
Infiniti M car? Sorry, I don't know the history here

Primo13
Posts: 2
Joined: Mon Jul 02, 2018 4:53 pm
Car: 08' M35X

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Nelson/ Enigma- Thanks for the input, greatly appreciated!

EniGmA1987
Posts: 2257
Joined: Tue Apr 28, 2009 5:13 am
Car: '06 Infiniti M35 Sport

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Nelson Sandalwood wrote:
Wed Apr 03, 2019 1:18 pm
Infiniti M car? Sorry, I don't know the history here
Yep. Its been my performance car while still maintaining as much luxury as possible for about 4 years now. Been using Hondas as daily driver instead. Hey, if Forsberg can use these as a performance drift car I can use it as a performance beast too ok? :gapteeth: lol

Nelson Sandalwood
Posts: 10
Joined: Sun Mar 31, 2019 11:27 am
Car: M45

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EniGmA1987 wrote:
Thu Apr 04, 2019 9:44 am
Nelson Sandalwood wrote:
Wed Apr 03, 2019 1:18 pm
Infiniti M car? Sorry, I don't know the history here
Yep. Its been my performance car while still maintaining as much luxury as possible for about 4 years now. Been using Hondas as daily driver instead. Hey, if Forsberg can use these as a performance drift car I can use it as a performance beast too ok? :gapteeth: lol
Yea, I have a JDM Juga 450, and thats my goal, performance and comfort. So I am looking shift the rear to 4.3 ratio and probably a quaife atb.


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