Gears!!
05-08-2014, 10:49 PM
#1
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Join Date: Apr 2014
Posts: 18
Gears!!
How's everyone? I've been researching mods for quite sometime now since I've gotten my Z.. I have a 95 with stock engine no upgrades yet. I want to know what would be some good gears to put on the rear-end? I'd also like to know whats the difference of the ratios (2.73, 3.23, 3.73, etc.) and what ratio would be recommended? I'm still pretty new to all this so with the car talk you might have to dumb it down some lol.. Thanks for any help
05-09-2014, 07:21 AM
#2
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,644
Re: Gears!!
The rear axle gear ratio is the ratio of the number of turns the driveshaft makes for each rotation of the tires. The higher the numerical gear ratio, the the more the torque from the driveshaft is multiplied, and applied to the rear wheels. The car will leave the line faster with a higher numerical gear ratio. The downside of the higher numerical gear ratio is a reduction of fuel mileage (extent of reduction depends on the transmission you have) and higher engine RPM at any given speed in a particular gear. If you are racing, and shifting near the engine redline, you will be shifting sooner (lower MPH in each gear) with the higher numerical rear axle ratio.
You need to tell us which transmission you have - 4-speed automatic ("A4") or 6-speed manual ("M6"). The A4 has a single overdirve gear ratio, so fuel mileage will suffer worse from a higher gear ratio. The M6 has two overdrive gear ratios, and using 6th gear will negate the effects of the higher rear axle ratio.
The A4 came with either 2.73:1 rear axle (RPO code "GU2" - look on the service parts tag in your glove box), or 3.23:1 (GU5). The 3.23 will simply be a faster car than the 2.73. The most common choice for an upgrade would be 3.73 gears.
The M6 (94 and newer) came with a 3.42:1 rear axle (GU6). The M6 works well with 4.10 gears.
You need to tell us which transmission you have - 4-speed automatic ("A4") or 6-speed manual ("M6"). The A4 has a single overdirve gear ratio, so fuel mileage will suffer worse from a higher gear ratio. The M6 has two overdrive gear ratios, and using 6th gear will negate the effects of the higher rear axle ratio.
The A4 came with either 2.73:1 rear axle (RPO code "GU2" - look on the service parts tag in your glove box), or 3.23:1 (GU5). The 3.23 will simply be a faster car than the 2.73. The most common choice for an upgrade would be 3.73 gears.
The M6 (94 and newer) came with a 3.42:1 rear axle (GU6). The M6 works well with 4.10 gears.
05-09-2014, 09:51 AM
#3
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Thread Starter
Join Date: Apr 2014
Posts: 18
Re: Gears!!
The rear axle gear ratio is the ratio of the number of turns the driveshaft makes for each rotation of the tires. The higher the numerical gear ratio, the the more the torque from the driveshaft is multiplied, and applied to the rear wheels. The car will leave the line faster with a higher numerical gear ratio. The downside of the higher numerical gear ratio is a reduction of fuel mileage (extent of reduction depends on the transmission you have) and higher engine RPM at any given speed in a particular gear. If you are racing, and shifting near the engine redline, you will be shifting sooner (lower MPH in each gear) with the higher numerical rear axle ratio.
You need to tell us which transmission you have - 4-speed automatic ("A4") or 6-speed manual ("M6"). The A4 has a single overdirve gear ratio, so fuel mileage will suffer worse from a higher gear ratio. The M6 has two overdrive gear ratios, and using 6th gear will negate the effects of the higher rear axle ratio.
The A4 came with either 2.73:1 rear axle (RPO code "GU2" - look on the service parts tag in your glove box), or 3.23:1 (GU5). The 3.23 will simply be a faster car than the 2.73. The most common choice for an upgrade would be 3.73 gears.
The M6 (94 and newer) came with a 3.42:1 rear axle (GU6). The M6 works well with 4.10 gears.
You need to tell us which transmission you have - 4-speed automatic ("A4") or 6-speed manual ("M6"). The A4 has a single overdirve gear ratio, so fuel mileage will suffer worse from a higher gear ratio. The M6 has two overdrive gear ratios, and using 6th gear will negate the effects of the higher rear axle ratio.
The A4 came with either 2.73:1 rear axle (RPO code "GU2" - look on the service parts tag in your glove box), or 3.23:1 (GU5). The 3.23 will simply be a faster car than the 2.73. The most common choice for an upgrade would be 3.73 gears.
The M6 (94 and newer) came with a 3.42:1 rear axle (GU6). The M6 works well with 4.10 gears.
I have a 4-speed automatic but eventually I want to change to a manual
05-09-2014, 10:14 AM
#4
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,644
Re: Gears!!
Changing the gears is unfortunately fairly expensive. You can get the gears (ring and pinion) for $160-200. An install kit will run from $80-140, depending mainly on how many of the bearings you change out. With a high mile car, I would opt for the full replacement kit.
Expensive part is the install. Gears are fairly difficult to "set up". Takes specialized tools like a pinion depth checker, and a magnetic dial indicator. If they aren't "perfect", they can howl like a screaming banshee. So for most people, you are looking at an install cost of $250-350. I have a lot of tools, have been working on cars for decades, but I have always left gear installs to professionals with very good references.
Expensive part is the install. Gears are fairly difficult to "set up". Takes specialized tools like a pinion depth checker, and a magnetic dial indicator. If they aren't "perfect", they can howl like a screaming banshee. So for most people, you are looking at an install cost of $250-350. I have a lot of tools, have been working on cars for decades, but I have always left gear installs to professionals with very good references.
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