G37S Sedan on 3.916 Gears - OH MY GOD
03-11-2013 | 10:48 PM
#1
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Joined: Oct 2011
Posts: 127
Likes: 12
From: San Diego, CA
G37S Sedan on 3.916 Gears - OH MY GOD
Hey Guys,
I just had my final drive gears swapped at SpecialtyZ in California for some 3.916 gears from a Nissan Frontier. As you may know, the standard gear ratio in this car for the autos is 3.3.
All I can say is...WOW!!!!
This is how the car should have been from the factory. Highway RPM's are only up 250-300 or so. 80mph is 3k RPM now.
However, the acceleration of the car is DRAMATICALLY improved. The car wants to go with the slightest bit of gas now! It's just way easier to get it moving. Clocked a 0-60 at around 4.5 seconds. Fantastic mod for the money, this is easily the biggest NA mod you could do to make this car "wake up" and be sporty and quick.
Just thought I'd share :P
I just had my final drive gears swapped at SpecialtyZ in California for some 3.916 gears from a Nissan Frontier. As you may know, the standard gear ratio in this car for the autos is 3.3.
All I can say is...WOW!!!!
This is how the car should have been from the factory. Highway RPM's are only up 250-300 or so. 80mph is 3k RPM now.
However, the acceleration of the car is DRAMATICALLY improved. The car wants to go with the slightest bit of gas now! It's just way easier to get it moving. Clocked a 0-60 at around 4.5 seconds. Fantastic mod for the money, this is easily the biggest NA mod you could do to make this car "wake up" and be sporty and quick.
Just thought I'd share :P
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03-12-2013 | 03:40 AM
#3
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Joined: Oct 2011
Posts: 127
Likes: 12
From: San Diego, CA
Sadly, nothing incredibly scientific. Took a 0-60 vid and that's how I got the time. I'll upload it later, kind of lazy right now haha.
I've heard some guys with more bolt on mods than me and 4.08 gears (vs 3.9 like I installed) have gotten closer to 4 seconds
I've heard some guys with more bolt on mods than me and 4.08 gears (vs 3.9 like I installed) have gotten closer to 4 seconds
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03-12-2013 | 10:02 PM
#11
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Joined: Oct 2011
Posts: 127
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From: San Diego, CA
Hey Guys,
I didn't expect such a response! I'll try to address everyone's questions:
@G37Sam: I may be doing an AutoX event in April, which may let me do an official 1/4 mile time. Until then I might be able to do something unofficial such as my solution with the 0-60 time. I'll see if I can find a suitable test are this weekend.
@thebiglubinsky: If you have a manual car, this mod for the parts + installation from a reputable shop will run about $1500. If you have an auto, you will need to also buy a differential off of a manual 350z/g35 or 370z/g37 that had the limited slip option. These diffs typically run $300-500 shipped on eBay, so your total cost ends up being $1800-2000 if you are doing this on an automatic car. The price includes brand new gears in the appropriate gearing from Nissan (Nissan Frontier gears), gaskets, internal parts, etc. and installation. The shop I did this at, SpecialtyZ, is in Chatsworth, CA, which is about 5.5 hours away from the Bay Area. They are by far one of the best names in the tuning industry and especially popular with the older Nissan 300ZX cars but they are very knowledgeable about our cars too. They did the whole differential gear swap in a few hours with 0 complications and did some other things to my car as well such as installing a 25 row GTM oil cooler. I'm getting headers and an Uprev tune done by them as well in a few months.
@BLamb: The 7AT needed to drive about 50 miles with it before it could adjust properly. It was confused initially it seemed and would flare when upshifting frequently but that isn't an issue after those first 50 miles. The only other quirk is that since throttle input has a greater response from the car, to let it slip into 7th on the highway you need to ease up very slightly on the gas when you get to your cruising speed. Other than that, the transmission is fine and does a bit less hunting in my opinion since you have greater acceleration in every gear. Not nearly as many 2 gear downshifts from applying half throttle on the highway, it just goes and goes quick.
@SharpByCoop: My car is an auto, so I went from 3.3 gearing to 3.9 which is a big difference. I did have to buy a manual diff to enable the swap, but it was so worth it to me. They took the manual diff, installed the new gears/calibrated them, then they swapped the driveshaft flange from my automatic diff to the new one. Not too bad, just more expensive. Cruise control only seems to work under 30 miles per hour, faster than that and it beeps and shuts off after a second.
@bluedevils95: With the 3.9 gearing, I can say that my highway mpg just cruising is only down maybe 0.5 -1 mpg. This is because it is not as aggressive as the 4.08 gearset that is typically used. For instance, at 75mph cruising I'm at 3k RPM even, which is definitely reasonable. The higher RPM is also offset by the fact that the car is a lot easier to get moving, and feels like it has more torque. This means you do not need to mash the pedal nearly as often and you can keep the car in a gear without it downshifting 2 gears and blasting off trying to respond to your input. In the city my mileage is actually very slightly better, due to it being easier to get the car moving. Obviously if you step on it all the time to test your new torquey ride you will see mpg losses :P One of the reasons I chose 3.9 over 4.08 gearing is that the 4.08 had too much highway mpg losses for me to make it worth the extra 5% torque multiplication. 370Z's with 4.08 gears from what I read lose 1-2 mpg highway, not sure about city.
I didn't expect such a response! I'll try to address everyone's questions:
@G37Sam: I may be doing an AutoX event in April, which may let me do an official 1/4 mile time. Until then I might be able to do something unofficial such as my solution with the 0-60 time. I'll see if I can find a suitable test are this weekend.
@thebiglubinsky: If you have a manual car, this mod for the parts + installation from a reputable shop will run about $1500. If you have an auto, you will need to also buy a differential off of a manual 350z/g35 or 370z/g37 that had the limited slip option. These diffs typically run $300-500 shipped on eBay, so your total cost ends up being $1800-2000 if you are doing this on an automatic car. The price includes brand new gears in the appropriate gearing from Nissan (Nissan Frontier gears), gaskets, internal parts, etc. and installation. The shop I did this at, SpecialtyZ, is in Chatsworth, CA, which is about 5.5 hours away from the Bay Area. They are by far one of the best names in the tuning industry and especially popular with the older Nissan 300ZX cars but they are very knowledgeable about our cars too. They did the whole differential gear swap in a few hours with 0 complications and did some other things to my car as well such as installing a 25 row GTM oil cooler. I'm getting headers and an Uprev tune done by them as well in a few months.
@BLamb: The 7AT needed to drive about 50 miles with it before it could adjust properly. It was confused initially it seemed and would flare when upshifting frequently but that isn't an issue after those first 50 miles. The only other quirk is that since throttle input has a greater response from the car, to let it slip into 7th on the highway you need to ease up very slightly on the gas when you get to your cruising speed. Other than that, the transmission is fine and does a bit less hunting in my opinion since you have greater acceleration in every gear. Not nearly as many 2 gear downshifts from applying half throttle on the highway, it just goes and goes quick.
@SharpByCoop: My car is an auto, so I went from 3.3 gearing to 3.9 which is a big difference. I did have to buy a manual diff to enable the swap, but it was so worth it to me. They took the manual diff, installed the new gears/calibrated them, then they swapped the driveshaft flange from my automatic diff to the new one. Not too bad, just more expensive. Cruise control only seems to work under 30 miles per hour, faster than that and it beeps and shuts off after a second.
@bluedevils95: With the 3.9 gearing, I can say that my highway mpg just cruising is only down maybe 0.5 -1 mpg. This is because it is not as aggressive as the 4.08 gearset that is typically used. For instance, at 75mph cruising I'm at 3k RPM even, which is definitely reasonable. The higher RPM is also offset by the fact that the car is a lot easier to get moving, and feels like it has more torque. This means you do not need to mash the pedal nearly as often and you can keep the car in a gear without it downshifting 2 gears and blasting off trying to respond to your input. In the city my mileage is actually very slightly better, due to it being easier to get the car moving. Obviously if you step on it all the time to test your new torquey ride you will see mpg losses :P One of the reasons I chose 3.9 over 4.08 gearing is that the 4.08 had too much highway mpg losses for me to make it worth the extra 5% torque multiplication. 370Z's with 4.08 gears from what I read lose 1-2 mpg highway, not sure about city.
Last edited by ap0c0lypt1c; 03-12-2013 at 10:08 PM.
03-13-2013 | 12:51 AM
#12
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Joined: Dec 2010
Posts: 554
Likes: 56
From: Norwalk, CT
VERY informative post. Nicely explained. Props.
I'm not there yet, but this swap is in my cards. My 5AT already has 3.69:1 gears, so I'd want to go to the 4.08 conversion. I'm impressed that the Frontier diff has both ranges.
Thank you. Keep us posted!
JIm
I'm not there yet, but this swap is in my cards. My 5AT already has 3.69:1 gears, so I'd want to go to the 4.08 conversion. I'm impressed that the Frontier diff has both ranges.
Thank you. Keep us posted!
JIm
