G37S Sedan on 3.916 Gears - OH MY GOD
10-24-2014, 09:09 AM
#106
Sorry I'm a moron but what's a peg leg diff?
I really want to do this for the increased acceleration but probably can't until at least early next year. I owned a 335i and hated the $500 problems that came up every month or two (owned it until over 100k).
I just miss the acceleration of the line a little and it sounds like this mod throws us right back into that stratosphere... does that sound right to you?
FYI: G37>BMW any day. I owned the BMW and it's reliability just plain sucks. I did have the 07 though.
Anyone know someone in the Tampa area that I could go to and they will know what the hell I'm talking about when I say to do this. Looks like Lokey infiniti in Sarasota has experience.
I really want to do this for the increased acceleration but probably can't until at least early next year. I owned a 335i and hated the $500 problems that came up every month or two (owned it until over 100k).
I just miss the acceleration of the line a little and it sounds like this mod throws us right back into that stratosphere... does that sound right to you?
FYI: G37>BMW any day. I owned the BMW and it's reliability just plain sucks. I did have the 07 though.
Anyone know someone in the Tampa area that I could go to and they will know what the hell I'm talking about when I say to do this. Looks like Lokey infiniti in Sarasota has experience.
Looked up Peg Leg online. Turns out my cousin vinny is very educational and I didn't even know it.
10-24-2014, 02:35 PM
#108
Does make sense.
Do you think your 0-60 is now in the mid to upper 4s?
I know bad measuring stick but I have to know. and it seems rpm's is only a little higher at 80mph?
10-25-2014, 08:15 AM
#111
10-25-2014, 08:25 AM
#112
^^^ Great vid!
NBS: although the TT will be able to pull longer gears, it's also able to spool up in addition to them. You know this.
NO gearing which will contain first gear on a twin-turbo is going to be as much fun from 2nd-6th. That's the tail wagging the dog.
Just limit that right foot for a moment.
To recap:
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.
Part numbers for 4.08 Frontier gears? (I even read on a spec chart that a model Frontier also has 4.36:1 diff. Oh, my....)
Coop
NBS: although the TT will be able to pull longer gears, it's also able to spool up in addition to them. You know this.
NO gearing which will contain first gear on a twin-turbo is going to be as much fun from 2nd-6th. That's the tail wagging the dog.
Just limit that right foot for a moment.To recap:
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.
Part numbers for 4.08 Frontier gears? (I even read on a spec chart that a model Frontier also has 4.36:1 diff. Oh, my....)
Coop
The automatic differential doesn't come into play at all besides swapping the flange. You don't need to open the auto diff at all, there is a small difference on the inside (even though physically from the outside they look identical) that prevents the shorter gears from fitting properly.
When you buy the manual diff from the 350/370z or the g35/g37 (any year will work for those as long as it is the VLSD diff, otherwise the inside will not be big enough) you actually swap the 4.08 gears into the manual diff and put the manual diff on your car. The only thing you do to the auto diff is remove the driveshaft flange and swap it onto the manual diff so you can use your stock auto driveshaft.
Unfortunately, I don't know the 4.08 gear part number but the part number for the 3.916 gears is 38100-0B66A from Nissan. I believe the frontiers have 3.916, 4.08, and 4.36 gears available to use in our cars.
So basically you have:
1. Acquire an entire Manual VLSD Differential w/ housing from any year 350z/370z/g35/g37. In my case the differential came off of a 2010 6mt g37 coupe.
2. The shop will open the manual pumpkin you bought and install the Frontier gears into it. This is where the calibration comes into play, the gears need to be able to activate the VLSD portion (since it's not a clutch-type LSD, it relies on exact speeds and pressures,) and not whine at any speed. There are other parts you need as well like crush collar, shims, gaskets etc but any reputable shop should be able to figure it out. Here is what Sebastian@SpecialtyZ quoted me for parts:
4.08 Gears $535
Seals, bearings, shims, crush collar, etc.. $300
$29 for Redline Gear Oil GL-5
Note that if you go to a different shop your mileage may vary, and as always labor rates end up being different. Mine came out to about $500 in labor.
3. At this point they will remove the auto diff from your car and swap the driveshaft flange from your diff to the manual one that now has the 4.08 gears inside.
4. The manual diff at this point becomes "plug and play" if it is off a G37 or 370z. The G35 and 350z diffs at this step have a threaded hole on the output shafts connecting the diff to the wheels whereas the G37/370z ones have a smooth, non-threaded hole and a small amount of work is needed to get those to line up properly but it isn't hard to do. Also note that if your car was NOT originally equipped with a VLSD diff (i.e., if you have a non-sport G37) you will need 1 different output shaft to make a VLSD diff fit your car. Regardless, any shop will be able to put the diff in the car at this point.
5. Then they would put your car back together and you'd be good to go! If you are auto you lose cruise control pretty much guaranteed, but as a note cars with the 6MT transmission don't have that problem (different cruise control logic, so their cars don't have any issues with cruise control w/ non-stock gearing)
6. The leftover parts you end up having are: Your entire auto differential with the stock gears in it, but with the manual driveshaft flange, and a spare set of the 3.6 gears from the manual differential. You can sell the auto differential and gears to recoup a significant portion of the costs.
When you buy the manual diff from the 350/370z or the g35/g37 (any year will work for those as long as it is the VLSD diff, otherwise the inside will not be big enough) you actually swap the 4.08 gears into the manual diff and put the manual diff on your car. The only thing you do to the auto diff is remove the driveshaft flange and swap it onto the manual diff so you can use your stock auto driveshaft.
Unfortunately, I don't know the 4.08 gear part number but the part number for the 3.916 gears is 38100-0B66A from Nissan. I believe the frontiers have 3.916, 4.08, and 4.36 gears available to use in our cars.
So basically you have:
1. Acquire an entire Manual VLSD Differential w/ housing from any year 350z/370z/g35/g37. In my case the differential came off of a 2010 6mt g37 coupe.
2. The shop will open the manual pumpkin you bought and install the Frontier gears into it. This is where the calibration comes into play, the gears need to be able to activate the VLSD portion (since it's not a clutch-type LSD, it relies on exact speeds and pressures,) and not whine at any speed. There are other parts you need as well like crush collar, shims, gaskets etc but any reputable shop should be able to figure it out. Here is what Sebastian@SpecialtyZ quoted me for parts:
4.08 Gears $535
Seals, bearings, shims, crush collar, etc.. $300
$29 for Redline Gear Oil GL-5
Note that if you go to a different shop your mileage may vary, and as always labor rates end up being different. Mine came out to about $500 in labor.
3. At this point they will remove the auto diff from your car and swap the driveshaft flange from your diff to the manual one that now has the 4.08 gears inside.
4. The manual diff at this point becomes "plug and play" if it is off a G37 or 370z. The G35 and 350z diffs at this step have a threaded hole on the output shafts connecting the diff to the wheels whereas the G37/370z ones have a smooth, non-threaded hole and a small amount of work is needed to get those to line up properly but it isn't hard to do. Also note that if your car was NOT originally equipped with a VLSD diff (i.e., if you have a non-sport G37) you will need 1 different output shaft to make a VLSD diff fit your car. Regardless, any shop will be able to put the diff in the car at this point.
5. Then they would put your car back together and you'd be good to go! If you are auto you lose cruise control pretty much guaranteed, but as a note cars with the 6MT transmission don't have that problem (different cruise control logic, so their cars don't have any issues with cruise control w/ non-stock gearing)
6. The leftover parts you end up having are: Your entire auto differential with the stock gears in it, but with the manual driveshaft flange, and a spare set of the 3.6 gears from the manual differential. You can sell the auto differential and gears to recoup a significant portion of the costs.
)You guys are great by the way. Really like the g37 community. Also 3.9 vs 4.08 should just be a little more acceleration vs a little less gas mileage? I think the 3.9 sounds like a good balance.
10-25-2014, 11:44 AM
#114
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.
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zmanfarlee (10-25-2014)
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zmanfarlee (10-25-2014)
10-25-2014, 01:49 PM
#116
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.
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zmanfarlee (10-25-2014)
10-25-2014, 01:58 PM
#117
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;-)
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zmanfarlee (10-25-2014)
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conkus805 (10-26-2014)