08-17-2013, 04:02 PM | #1 |
Drives: 2000 Camaro SS Join Date: Feb 2010
Location: Louisville, Ky.
Posts: 25,179
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Swappin' Gears
Warning: Installation of rear end gears should only be performed by professionals. As owners of the 5th generation Camaro continue their pursuit of more performance, many are swapping to a more aggressive set of rear end gears. While not an inexpensive modification, the bang for your buck with a rear end gear swap is hard to beat and the improvement in performance is dramatic. Making this sort of modification can be intimidating because many people don’t understand differentials and gearing. In this post I will try to provide some basic information to at least try and help get you pointed in the right direction. How It Works The rear differential is the device that transmits torque and rotation from the driveshaft to the rear axles which then drives the rear wheels. The rear end gears contain a ring and pinion gear that can be swapped to different ratios. The stock Camaro comes with either a 3.27 (all V6 models and the automatic SS) or a 3.45 (manual SS) rear end gear ratio. This means that for every 3.27 or 3.45 rotations of the drive shaft your rear wheels will turn once. A lower gear ratio means increased torque and increased acceleration without the engine having to create any additional power. This all sounds great but the are some potential draw backs. A lower gear ratio means that your engine has to turn faster at cruising speeds which means fuel mileage can suffer. In the case of the 5th generation Camaro, the new six speed transmissions help mitigate the impact of this. Camaro owners that do a lot of highway miles have been reporting a loss of about 1-2 MPG, while those who drive mostly in town are reporting no change and even an increase in some cases due to the engine not having to work as hard to get up to speed. The other potential draw back is that a lower gear ratio will shave away top end speed. This is not important to the average Joe since the Camaro is capable of speeds well beyond the speed limit right off the showroom floor, but for competitive drag racers it can be. It is possible that while the lower ratio will cause your car to accelerate faster it can also cause you to have to shift gears one more time before you cross the finish line, potentially sacrificing the gains made. Careful calculations should be made when selecting the correct ratio for these sorts of applications. The Numbers Camaro V6 Models Currently, there is only one gear ratios made specifically for the 5th generation V6 Camaro. For the V6 Camaros Richmond manufacturers a 3.55 gear ratio. With the stock 3.27s the automatic (A6) equipped V6 runs 1750 RPM at 70 MPH. Swapping to the 3.55s provides an equivalent torque gain of approximately 10% or 27.3 ld.-ft. of torque and will raise 70 MPH cruising RPM to 1949. The V6 Camaros equipped with the manual transmission (M6) come with 3.27s and run 2000 RPM at 70 MPH. Swapping to the 3.55s provides an equivalent torque gain of approximately 9% or 27.3 ld.-ft. of torque and will raise 70 MPH cruising RPM to 2167. The rear end in the M6 equipped V6 Camaro is similar enough to the SS that their gears will also work. Apex Motorsports recently had a customer install Richmond 3.73s in his car. The result was an equivalent torque gain of approximately 15% or 40.95 lb.-ft. of torque and will raise 70 MPH cruising RPM to 2277. Camaro SS Models The Camaro SS models currently have three aftermarket gear ratios available for them; 3.73, 3.91, 4.11, and 4.33. When equipped the the automatic transmission (A6) the SS comes with a 3.27 rear end and cruises at 1795 RPM at 70 MPH. By upgrading the factory 3.27s in the stock A6 equipped Camaro SS to the 3.73s you will realize an equivalent torque gain of approximately 15% or 61.5 lb.-ft. of torque and cruise at 2050 RPM at 70 MPH. By upgrading the factory 3.27s in the stock A6 equipped Camaro SS to the 3.91s you will realize an equivalent torque gain of approximately 20% or 82 lb.-ft. of torque and cruise at 2150 RPM at 70 MPH. By upgrading the A6 to the 4.11s you will realize an equivalent torque gain of approximately 27% or 110.7 lb.-ft. of torque and cruise at 2250 RPM at 70 MPH. By upgrading the A6 to the 4.33s you will realize an equivalent torque gain of approximately 33% or 135.3 lb.-ft. of torque and cruise at 2377 RPM at 70 MPH. The A6 transmission is geared more aggressively than the M6 SS so we have found that 3.73 is a great gear for most A6 equipped SS applications. When equipped with the manual transmission (M6) the SS comes with a 3.45 rear end and cruises at 1612 RPM at 70 MPH. By upgrading the factory 3.45s in the stock M6 equipped Camaro SS to the 3.73s you will realize an equivalent torque gain of approximately 10% or 42 lb.-ft. of torque and cruise at 1750 RPM at 70 MPH. By upgrading the stock M6 equipped Camaro SS to 3.91s you will realize an equivalent torque gain of approximately 13% or 54.6 lb.-ft. of torque and cruise at 1800 RPM at 70 MPH. By upgrading the stock M6 equipped Camaro SS to 4.11s you will realize an equivalent torque gain of approximately 20% or 84 lb.-ft. of torque and cruise at 1915 RPM at 70 MPH. By upgrading the stock M6 equipped Camaro SS to 4.33s you will realize an equivalent torque gain of approximately 25% or 105 lb.-ft. of torque and cruise at 2025 RPM at 70 MPH. We have found that the 3.91s and 4.11s are great gear options for most M6 equipped SS street applications. Once the 550-600 rear wheel horsepower range is reached we recommend dialing back to 3.73 unless the vehicle has a very solid suspension package and a very competent driver. Make It Happen Hopefully, the information in this post has helped you better understand gear swaps. If you think a gear swap may be right for your project be sure to consult a professional, like the experts at Apex Motorsports, during your decision making process. Last edited by Apex Motorsports; 10-02-2013 at 10:45 AM. |
08-17-2013, 05:30 PM | #2 |
Drives: 2010 RJT 2SS/RS Join Date: May 2012
Location: Staten Island, NY
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Great info like always Chase
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08-17-2013, 09:07 PM | #3 |
Plays with Hot Wheels
Drives: '17 Jet Black ZL1 Join Date: Apr 2010
Location: Derby, Kansas
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I'm no math wiz, but I'm guessing that in an M6 car going to 3.91's over the stock 3.45's would be around 15% gain for approximately 63 more lbs.tq......right?
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08-18-2013, 10:45 AM | #4 |
Drives: 2000 Camaro SS Join Date: Feb 2010
Location: Louisville, Ky.
Posts: 25,179
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Thanks!
It is the weekend and I can't force myself to do the math right now but that is about right. |
08-18-2013, 05:27 PM | #5 |
instigator
Drives: 2020 6.2 Trail Boss, 2022 XC90 Join Date: Jan 2010
Location: 72034
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4.33 would rock on a track if u can hook it. Fat car likes gears.
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08-18-2013, 08:42 PM | #6 |
Good info as I am thinking of switching gears. Thanks
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08-19-2013, 07:13 PM | #7 |
Drives: 2000 Camaro SS Join Date: Feb 2010
Location: Louisville, Ky.
Posts: 25,179
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08-19-2013, 08:40 PM | #8 |
Love my 3.91's, they're a great set in an M6 SS
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08-19-2013, 10:27 PM | #9 |
Drives: 2016 1LT RS Camaro; 72 Chevelle Join Date: Apr 2008
Location: Central Point, OR
Posts: 5,688
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Nice write up! Should add info about the 2.92 ratio in the 2ls automatic, and perhaps show the mathematical benefit of swapping to even the 3.27 auto v6 gears or the 3.55.
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08-19-2013, 10:48 PM | #10 |
Always bet on Black
Drives: 2011 turbo LS, 2012 f 150, Join Date: Nov 2010
Location: Concord Nc
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Great info
sent form my mini computer note 2 |
08-20-2013, 08:09 AM | #11 |
Drives: 2011 2SS/RS Black Join Date: Feb 2011
Location: Hillsborough, NJ
Posts: 233
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What do you think of the 3.73 vs. the 3.91 for the A6?
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08-20-2013, 10:06 AM | #12 |
Drives: 2013 camaro ls; 2005 rx8 Join Date: Mar 2013
Location: Houston
Posts: 577
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Where can i find more info on this? As i have a 2ls...any help or info on where to rwad up on this is greatly appreciated...thanks!
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08-20-2013, 10:12 AM | #13 |
Drives: 2017 ZL1 A10 & 2021 BMW M340i x Dr Join Date: Mar 2009
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I know yours is a SS and mine is the RS, but i will have a good answer for you tomorrow. I stepped up to 3.73 from 3.27 a few months ago and tomorrow we needed to do a gear swap and only thing on hand is a set of 3.91's. I will post back if i see much of a difference in performance, regular driving, and mpg.
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08-20-2013, 10:21 AM | #14 | |
Drives: 2011 2SS/RS Black Join Date: Feb 2011
Location: Hillsborough, NJ
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3.73, 3.91, 4.11, gear ratio, gears swap |
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