Originally Posted by Ivoidwarranties

This is a subject I've looked into a little. Word is the carrier assembly is different between the autos and manuals. The gears fit the larger housing (manual) but not the smaller one (auto). Meaning you would have to swap out the whole rearend. There is also talk about the cruise control not working after the swap for the auto but either no one knows why are they just aren't saying. A lot of this is correct information for the G35/350Z from a few years ago but I don't know if it's true for the G37/370Z or if it's just info carried forward.

I would do this mod in a heartbeat if it didn't effect cruise control. If I disabled cruise control on Her car I don't think she would ever let me touch it again.

This would cost me over two grand to do this mod as well. New or used carrier assembly from a manual, gears and parts, labor for install, and a new LSD. The aftermarket LSD's start at like a grand. I'd do almost all the labor except setting the gears. One of the other sites had a great post showing all the differentials available and the pros and cons of each but I can't find it again.

Originally Posted by planoyzfr1

I don't believe anywhere did i speak of unlimited traction? Was there a typo somewhere in my post? My point here was that unless you are traction limited gears will increase your acceleration 99% of the time (yes you can get stupid with all things including gearing like going too high causing your gears to be so short that you actually lose time due to excessive shifting). Now the method that your car creates that power weather it's supercharging, turbos, NOS, or stroker motors makes almost no difference as long as it's designed well. I was merely pointing out that anyone who makes generalizations like "Gears are terrible for turbos, but great for superchargers" doesn't have any idea what they are talking about.



Spinning your tires in first gear is not the same as being traction limited. Unless you are consistently having trouble keeping traction in the first 3 gears you can usually improve acceleration by increasing the gear ratio. If you are honestly having this much traction issues (which I highly doubt since my 600hp blown V8 in the z06 didn't have this much trouble) you should probably look at reducing the gear ratios.



My experience comes from 15 years of working on cars in my own garage with my own hands. I'm not sure what "big boy's toys" you are referring to but my last 2 cars were both blown V8s. A 95 5.0 mustang with Vortech and the last was an 03 Z06 with a Paxton that I traded in for the G - I still miss the Z06

Anyway - It seems maybe there was some misunderstanding .. my post was just meant to educate on gear ratios, it seems that this is a relatively new topic for G/Z owners but it's one that I have a lot of personal experience with.

Happy Motoring

-C

Originally Posted by Q8y_drifter

I don't understand why Nissan would change the diff housing between the auto and manual models. I mean the 6MT and the 5AT both have a stock 3.69:1 FD while the 7AT has a 3.36:1 FD. can you confirm whether the difference in housing size is for ALL auto's or just the 7AT?

Originally Posted by Q8y_drifter

It would make sense if Nissan used a smaller housing on the 7AT since a 3.36:1 ratio would mean the ring and pinion gears would probably have different dimensions.

Originally Posted by Q8y_drifter

On another note, is the diff housing different from previous model G's and Z's? If they're the same, then swapping out the diff housing (assuming the mounting points and the splines on the input and output shafts are the same) should be easy and relatively cheap.

Originally Posted by Q8y_drifter

And one final question, is the spline on the pinion the same for both auto and manual?

Originally Posted by Q8y_drifter

Is it this one?

Which Diff? - Nissan 370Z Forum

I was reading thread thread about a week ago. There's a lot more on the 370 forum.

Originally Posted by Z1Performance

to the OP
there is another thread that goes through the differences
The Carbonetics is a nice unit. Some (350Z's) have experienced issues with premature disk wearing, even using Carbonetics own fluid. I personally have never experienced it. The Carbon units they offer are not adjustable, so it does not allow for any customization now or down the road. That may or may not be an issue for you. They also require frequent fluid changes (every 3-5k miles) because the carbon dust from the disks contaminates the fluid. They are very smooth however and work well. You also are stuck using their fluid, so if you get it, stock up. We stock the diffs and the fluid BTW
Cusco - I've run one in my car since 2004 (I think...might be 2005!). It's a clutch type diff as well. It is adjustable from 1.5 to 2 way (2 way is for drift) and has 3 way adjustable lockup as well. With the right fluid, and the right setup (which IMHO is 60% lock, 1.5 way) it is nearly seemless. Mine makes zero noise. At a literal crawl at parking lot speeds you can slightly feel the inside wheel grabbing a touch...but you literally have to be crawling. At 5 mph, it's not present at all, for example. No special break in (no figure 8's needed!) and can use off the shelf fluid. Downside is there is a wait time for them (45-60 days at present). They are reasonably priced.
OS Giken - another clutch type diff, but has a bit of a different design. They are adjustable from OS Giken via diferent springs. Extremely careful tolerances means it is quiet and smooth. I've used them several times now on the 350Z's and they are unlike any clutch type LSD I've ever used. Higher cost vs the Cusco by a few bucks, but it's a drop in for base model cars on a 350Z and 370Z.
Quaife - top notch firm from the UK that has made diffs since forever. Theirs is a helical (gear) based unit. It is not adjustable at all, but it is literally so quiet and smooth, Nissan could have installed it from the factory and you would never thing it was aftermarket. A great street oriented unit. Works well for club type track days also, but not what I'd use on a full out race car.
Drexler - amazing unit but very spendy. Used by several high end OEM manufacturers, and many race teams worldwide
You can compare prices, specs, etc on our site if you like
Z-1 Performance Automotive Services Inc.
Given your conditions and needs/wants, I would select the OS Giken if this were my own car. My second choice would be Quaife.

Originally Posted by MechE

Ratio is based off of the teeth on the ring vs. the teeth on the pinion. I would venture and say that all the ring gears are the same diameter only varying amounts of teeth. Same with the pinion. Although it is possible to vary the the teeth with a variable diameter.

Originally Posted by Q8y_drifter

That's what's confusing me, if the O.D of the ring gear is the same, why change the diff housing? Has anyone cracked open both diffs for a comparison? Even if it's the 2003+ G/Z.

Originally Posted by NeverBoneStock

Well almost everyone knows I have been waiting to install my new 4.08 final drive and after mnths of waiting all I can say is ... OMG. It hard to explain this for everyone to understand . This fcukin car should have came with these from the factory. It pulls like no other ! I can launch so much better . It gets into the powerband way faster to. This isnt a review but if anyone who is staying NA or plan on having a SC installed like me . This is the mod to get. Its not cheap but well worth it . A few pics for ya...