ANMVQ

iTrader: (13)

No I was going to do that, But the motor has to come out to change it:/. Maybe next spring I'll find someone to just replaces the gears in the front. I have 3.70 rear set at the house just sitting in a box. I haven't even opened it yet LOL No reason yet. ;/

zer099

iTrader: (2)

Just wanted to share this information. The following chassis have a front diff that is a direct swap for our car and a 3.692 gear ratio:

2009-2012 FX35
2007-2008 G35X
2009-2010 M35X
2013-Present FX37

The FX37 is the only one not confirmed but it has the right gear ratio and right engine so it a 99% thing. Obviously I am talking about the AWD models as well.

The engine does not have to be dropped to do this, but you just as well to save you the headache and I recommend you just drop the engine to do this (not that my opinion should matter). It's one of those projects where you just as well have a set of cams to put in too and maybe some headers as well to make it all more then worth the effort.

The rear diff, of course, can be sourced from a 6MT G37. There is a thread on these forums that goes over the different types of input ends on the rear diffs and how to swap our AWD one over to a LSD one. Do you have to go LSD? No, but why not when it will only cost you maybe $50 more and only comes with advantages.

You will need to have your ECU reflashed for the new gear ratio, so that will have to be taken into consideration. But, the acceleration gains this would give someone going all out NA should be pretty awesome. I wouldn't recommend this much for someone going with boost as the lose of traction would most likely be considerate where our factory taller gearing is actually pretty well suited for boosted applications. But, that's an opinionated topic that everyone will have a different view on based on your wants, needs, and desires.

Happy holidays!

PS: Have I done this? No, but I will once I see what JWT is doing with their stage 2 cams. All the diff case part numbers match up (38511-AR50A), that's how I know they are direct swap plus I looked at the diff in my car and compared it to the 2010 FX35 one I got and they are the same case and will be a straight swap. All the part numbers for the stated chassis have the same final drive part number as well (38100-AR560), which is what all the FSM literature claims is a 3.692 gear ratio.

ANMVQ

iTrader: (13)

Funny cause this is till on my radar but I need to find a place to install my headers, first . I still haven't found a place I " trust" to do it. The last 2 places that had my car , left me with a cel light ( after market AF sensor) and a bunch of pin holes in my cats, not to mention a blown ECU :/.

zer099

iTrader: (2)

I read about your nightmare. That's horrible and I'm sorry you had to go through that. I would be sure to use the experience when looking for a new shop, share it with them and make sure the new shop says "we will warranty our work not to f*up your car". It will be hard to find a place like that, but they exist. Typically it will cost you more there but I've always felt it's worth it in the long run when using shops.

I still want to know how they managed to mess up so much crap on your car.

Upscale Speed

iTrader: (18)

Very interesting zer099. Cams, gears and re-tune would be super interesting to me. I am thinking Stillen SC next year, but this could change my mind. I want this car in the Mid 12's though. Not sure I'd get their with cams, gears and re-tune.

zer099

iTrader: (2)

Dsskyline is getting mid/high 12's with his RWD auto setup with a 3.692 final and your typical bolt-ons (CAI, z1 plenum, test pipes, CBE, re-tune, and pulleys). I think headers and cams for us with AWD and the 3.692 final will get us there as well if not a tad better. It's hard to say since we are talking the unknown; it's really just going to take one of us pulling the trigger to find out.

For the sake of keeping this information all in one place I've learned we also have a third final option available to us: 3.133 (38100-AR260). This gearing can be found in the 2007+ EX35 and EX37 AWD models. You would have to source the rear diff from the EX as well as it's the only rear diff I've found so far with a 3.133. I would only recommend this final if your all about the MPG or going for 450+ AWHP; in-which case this final would minimize wheel spin and put you in the high 120s low 130s MPH in fourth gear around 7500 RPM mark (depending on tire size choice), which should be putting you in the low 11 second range, if not better depending on factors. Food for thought.

Upscale Speed

iTrader: (18)

Dsskyline has pulleys? Which ones? I've been stewing on going with the Stillen OEM size lightweight crank pulley as I don't want to under drive my accessories.

It would be badass for us AWD guys to get well into the 12's NA. Also it should be a more reliable setup than a FI one and a lot cheaper.

ANMVQ

iTrader: (13)

I'm not sure he has pullies tho. With headers and gears we should be able to break into the 12's. I just got an email from a place I contacted about the header install ( ace performance ) and I'm going see how this goes and mention the gear swap, I'd even buy the gears and just have them instaled in the current diffs. But we'll see. If this goes as I hope I should have headers and gears buy spring time, get returned and I can hit the track and see how much better I can get than the last time. I know fink stayed longer I would have gotten better times than the 13.5 I didn't play with my launching RPM and almost every trip I f'd a shift lol.

oldbeezer

I haven't read all of this thread in detail but I think you may find some information in this thread (although I haven't read all of it in detail)
https://www.myg37.com/forums/engine-...-on-awd-g.html

ANMVQ

iTrader: (13)

I remember that thread but he makes a note and says" AWD do not change you rear gear Ratio" as the fronts have to be the same.