I'll get right to the point. The current 4.083 final drive gear option, comes as an OEM part from a Nissan Frontier. I believe its from the 1997 to 2004 models front differential which happens to be an R200A. Seeing as how the 4.083 requires no modifications to fit, then these shorter gears offered as upgrades to the Frontier's R200A, should also fit without modification to our R200.

Link.
http://ruggedrocksoffroad.com/fronti...35_40_847.html

It's the ones listed as Nismo 4.875 and Nismo 5.143. I personally don't have the resources to physically test one, but maybe someone else out there does?

TK

 

those are way to oo short. we need longer gears like 3.0

 

Guilty of seeing this from my point of view only. I have an 07 HR. Completely forgot the older cars didn't rev as high. Would be more than a complete downshift without the additional revs. Maybe you track guys?

 

TK,

There's another link in this forum that talks about the different final drive options. As far as aftermarket goes, they talk about the 4.083 being the shortest available for our Z's. It even lists the top speed at redline in each gear for the VQ, and for the HR engines. Sorry, I don't have a link, but I searched under "shorter final drive" and found the thread about it. I myself, haven't found anywhere that sold 4.083, but have found on the mynismo.com website a Central20 brand final drive that is 3.9. I believe the 6 MT for the HR has a 3.5 or 3.7 final drive stock, with redline in 6th gear around 216 MPH. I read that the 4.083 gears brings the redline top speed in 6th gear down to 179 MPH, which, IMO is more usable all around. If the factory Nissan Frontier final drive works in our rear end, then I'm all for it, if I can drop the 4.083 gears in.

The other gearing you mentioned at 4.875 and 5.143 are way too short, I think even for a small track. Guys with the 4.083 in the HR already can't even get traction in 1st. I can't imagine how horrible it would be with the shorter gears, not to mention the amount of extra shifting on a small track. Those shorter gears are clearly meant for 4X4 off road type events.

On a side note, the Central20 brand 3.9 gears list for around $520 on mynismo.com (correct me if I'm wrong). I checked with local transmission and rear end shops and I was told that labor could cost up to $500, depending on how difficult it is to get everything lined up correctly. Apparently, if you get this done from someone not experienced and knowledged, and it goes back together wrong, you'll be looking at blowing up your entire rear end within a week.

But please, let me know if that 4.083 from the Frontier works. I've been wanting to go this route, since I'm planning to stay N/A and honestly think that I would see the most difference/improvement in changing the rear end final drive, vs. spending the same amount on an exhaust system.

Str8dum1,

I may have misunderstood your post, and am not sure what the gearing in a 2003 G35 is, but I don't think even F/I guys go with gearing as tall as 3.00. And even if they did, I'd have to ask, "why???"

 

Usually the built motor guys with FI... need shorter gears.. so they can stay in boost longer.. for stock block 3.5 and FI is perfect I think.

 

I think you have it backwards, longer gears are more essential for boost. If you put shorter gears in you have better acceleration which is usually better for n/a, longer gears you have better top speed and don't accelerate as fast and shift as much and it is easier to get traction which seems to be ideal for boost.

 

one would need ~ 12k-13k rpm's to make anything remotely resembling a meaningful use of such a final drive, coupled with completely different transmission gear ratios

 

It also would probably not be a direct drop-in since most of our cars are fitted with R200Vs and not R200A. So it would be incorrect to make the assumption that it would be a direct swap. Lastly the 4.083 that does swap into our R200Vs does not come from the model you have listed.

 

that was the other thing I was going to mention ^

there are several iterations of the R200, and the vast majority don't work in a Z

 

What model does it actually come from?

Edit: Never mind, it was the wrong year. It's from the 2005-2007 C200 rear diff.

 

So if I were to want a 4.083 I could order a ring and pinion from a 05-07 Frontier's front diff?