G37S Sedan on 3.916 Gears - OH MY GOD

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Oct 25, 2014 | 05:23 PM

#121

johnnyn

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Quote:

Originally Posted by Solidus

In your case I'd just go for a 4.08 swap since you're 3.69 now. Buy a 6MT diff , have the gears installed , make money back off your old 3.69 by selling it to a 7at

Im a little hesitant as to how high my rpm would stay at if I went to 4.08. My 5at coupe currently runs 80mph at a little under 3300 rpm. Cruising 80mph at 3500-3700 sounds a bit taxing on the engine and mpg

Also, I was under the assumption that purchasing a 6mt vert differential would allow me to do a direct swap of my differential and not need to purchase/do steps 1 and 3 below. Did I assume wrong?

Quote:

1. The automatic differential guts need to be replaced by a manual LSD from ANY year 350/370/G35/G37?
2. Then a set of Frontier gears purchased and installed onto that pumpkin.
3. The automatic's pumpkin driveshaft flange needs to be swapped into the manual's pumpkin
4. Install, measure/fit and go.
5. Probable loss of cruise control.

Last edited by johnnyn; Oct 26, 2014 at 06:01 PM.

Oct 25, 2014 | 05:50 PM

#122

chuckie311

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From: Las Vegas

at 80 im running about 3300 with the 4.08s
gas mileage I don't care about..if I was worried about that I would have left my car stock

Oct 25, 2014 | 06:17 PM

#123

johnnyn

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Quote:

Originally Posted by chuckie311

at 80 im running about 3300 with the 4.08s
gas mileage I don't care about..if I was worried about that I would have left my car stock

Are you 5at, 6mt, or 7at?
Edit: Nvm I found out your 7at with some aftermarket exhaust/intake mods. A little difficult to use you as a comparison.
Edit 2: at 80mph my rpm is actually 3250(stock 5at coupe).

As an attempt to save cost.. If I buy the 6mt vert differential, would I still need to swap the flange and other parts? Or could I just swap the vert differential with my car's differential?

Sorry, I've read through this whole thread and a few others but gear ratio/differential mechanics is not an area I know very much about

Last edited by johnnyn; Oct 25, 2014 at 08:55 PM.

Oct 25, 2014 | 09:34 PM

#124

Solidus

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We were all in "Question Land" as recently as last week. I say go 6mt with 4.08 because 3.69 to 4.08 is equal to 3.36 to 3.69. Besides being less aggressive you would still need an LSD unless you're just a fan of one wheel peel. If I were you I would read some more. Here you'll have a few good threads and on 370z forum there are really good ones.
I took cues from everyone here and there and being almost done ( still getting a CF driveshaft ) there are some things I'd have done different but I'm damned glad I got it done.

Oct 25, 2014 | 10:54 PM

#125

zmanfarlee

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Quote:

Originally Posted by Solidus

Easiest way for you and knowing what I know now what I would've done: There's a G37 vert open diff on ebay right now for 299.00 . Buy that then source the best deal you can get on a Quaife lsd. Buy both, then recharge your funds and have the Quaife installed. After the installation . Bring your diff back home and recharge the funds again. Have it installed and boom!! No bolt on and quicker than all but those who have your mod.

Quote:

Originally Posted by Solidus

To top it off the vert diff is already 3.91 and guaranteed to keep cruise control and no codes. That is the perfect route in hindsight.

Quote:

Originally Posted by conkus805

Problem is, with an open diff there is not enough room to fit a quaif diff in the housing. The auto open diff is smaller than the manual with the vlsd so he would have to source a vert 3.90 diff from a manual transmission for the quaif install to work. This is also the reason the stub axles are different on the two pumpkins as well. With 3.90 gearing, you definitely do not want to run an open diff. You would never be able to hook up off the line. I have trouble with the lsd diff.

Quote:

Originally Posted by conkus805

To answer your question zman, the different shaft that apocalyptic was referring to was the stub axle that is connected to the diff, it's the part that the axel bolts up to. There is a difference in length on one side when comparing a lsd diff to an open diff. Best way to go, IMO, is to buy a 370z manual transmission diff with the vlsd and just swap the driveshaft flanges and be good. It will have 3.69 gears which are a nice upgrade. I was going to go that route but I got lucky and saw one on the classifieds that was a complete pumpkin with 3.90's and vlsd. So I snatched it up;-)

Thank you ALL! I want the 3.9 with everything. I'll just have to reread when I do this. ANy of you should expect a PM in a so many months to clarify. I'm excited!!!

Oct 26, 2014 | 01:21 PM

#126

conkus805

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From: california

I wish you luck, if you have any questions don't hesitate to ask. I'm sure either Solidus or I will be able to help you on this subject. Also SharpByCoop has a lot of knowledge on this subject as well, he was one of the first members to do a gear swap on this forum.