Thinking About Swappin' Gears? Here are the numbers! - Page 3 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Apex Motorsports · 04-21-2011, 07:37 AM

Quote:

Originally Posted by mpiper

I'm subscribed. One of my long term goals is to drop a posi 3.7/3.73 rear in. No rush, I want the warranty a bit longer on the stock drive-train so if anything breaks in the first year to 25k miles it's covered, but after that, the posi's going in. So as long as we have a solution, even if it's a custom drive-shaft or something similar, I'm game.

Last time I did this (with a 79 Grand Prix, so no comparison), I just took the stock drive-shaft, had the shop make measurements and a local shop did the cut&weld to give me a custom drive-shaft from the stock original. I'm hoping to do the same with this one.

I look forward to seeing it.

Rich1 · 04-21-2011, 12:51 PM

Here is some additional info I found at:

http://www.differentials.com/faq.html

What gear ratio do I need?

Differential Gear Ratio determines the number of times the drive shaft (or pinion) will rotate for each turn of the wheels (or ring gear). So if you have a 3.73:1 gear ratio the drive shaft turns 3.73 times for every turn of the wheel.

Gear ratio is calculated by dividing the number of teeth on the ring gear by the number of teeth on the pinion gear. The higher the number, the lower the ratio: a 5.29 gear has a lower ratio than a 4.10 gear. With a lower gear ratio the drive shaft (and thus the engine) turns more for each revolution of the wheel, delivering more power and torque to the wheel for any given speed. Lower ratios are generally desirable when going off-road. Higher ratios are better for freeway driving since they run at lower RPM's and offer better fuel economy.
Changing tire size affects the final drive ratio. Switching from a 30" tire to a 35" tire changes the final drive ratio by about 17%. This may drop the engine out of its' "power band" and result in poor performance and fuel economy. To restore performance you must change the gear ratio to compensate for the change in tire size. If you originally had 3.07 gears you need a ratio that is approximately 17% lower, such as 3.55. If you want to increase off road performance you might want a 4.10 or lower ratio.

Maurdib · 04-21-2011, 04:15 PM

So for us A6 V6 guys, how much MPG's can we expect to lose on the highway vs how much could this improve the 0-60 times?

Robbie1227 · 10-15-2011, 10:41 PM

Chase,
I have a slightly modded and tuned 2010 SS and am considering doing my rear end.
It's my daily driver, but I take it to the road track a several times a year for some fun. I would really like some more low and mostly mid range power to accelerate me out of the turns quicker, so I can haul down the straights.
Do you think 3:73 or 4:11, I am putting down 400 rwhp and 389 rwtq right now.
Rob

wsmith · 04-24-2017, 02:12 AM

What's the difference between swapping the gear ratio and moving to a V8 differential in a V6? When is it beneficial to sway to a V8 one? If I swap to a V8 differential before putting down enough horsepower, will I LOSE performance or have any adverse effects? But if I lay down enough horsepower before swapping the differential, will I damage anything?

04-21-2011, 04:15 PM	#31
Maurdib Drives: 2010 Black Camaro 2LT/RS Auto Join Date: Apr 2010 Location: San Fernando Valley Posts: 751 View My Garage	So for us A6 V6 guys, how much MPG's can we expect to lose on the highway vs how much could this improve the 0-60 times? __________________ BackInBlack Performance:Vararam cold air intake

10-15-2011, 10:41 PM	#32
Robbie1227 Drives: 2015 Camaro Z28/2016 Jeep Sahara Join Date: Mar 2010 Location: South Florida Posts: 544	Chase, I have a slightly modded and tuned 2010 SS and am considering doing my rear end. It's my daily driver, but I take it to the road track a several times a year for some fun. I would really like some more low and mostly mid range power to accelerate me out of the turns quicker, so I can haul down the straights. Do you think 3:73 or 4:11, I am putting down 400 rwhp and 389 rwtq right now. Rob __________________ 2015 summit white Z28 #120 TRK DAY -Sun-Tek PPF-C protection film on 2/3 of the car, Moreno Camber plates, American Racing 2" ceramic coated LT headers and X-pipes with No Cats, Taylor red performance wires, NGK plugs, BTR Stage III Cam, MSD Atomic intake, Nick Williams 102mm throttle body, Stage 2 CNC Ported Heads by WCCH, MGW short throw shifter, oil catch can, and a dyno tune to get me to 587 RWHP and 516 RWTQ GONE: 2013 Summit White Camaro ZL1 M6 Roto-Fab CAI, Kooks headers and CAT delete, ATI damper and 10% pulley and balancer! Results: 576 RWHP - 540 RWTQ

04-24-2017, 02:12 AM	#33
wsmith Drives: 2011 LS Join Date: Nov 2016 Location: Black Diamond, WA Posts: 61	What's the difference between swapping the gear ratio and moving to a V8 differential in a V6? When is it beneficial to sway to a V8 one? If I swap to a V8 differential before putting down enough horsepower, will I LOSE performance or have any adverse effects? But if I lay down enough horsepower before swapping the differential, will I damage anything? __________________ MRT V 1.0, Injen intake, ICE-olator, JVC Stereo, Alpine speakers, 600-w Amp, 10" Subs

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04-21-2011, 12:51 PM	#30
Rich1 Drives: 2023 ZL1 Camaro Hot Red Join Date: Dec 2009 Location: St. Louis Posts: 358	Here is some additional info I found at: http://www.differentials.com/faq.html What gear ratio do I need? Differential Gear Ratio determines the number of times the drive shaft (or pinion) will rotate for each turn of the wheels (or ring gear). So if you have a 3.73:1 gear ratio the drive shaft turns 3.73 times for every turn of the wheel. Gear ratio is calculated by dividing the number of teeth on the ring gear by the number of teeth on the pinion gear. The higher the number, the lower the ratio: a 5.29 gear has a lower ratio than a 4.10 gear. With a lower gear ratio the drive shaft (and thus the engine) turns more for each revolution of the wheel, delivering more power and torque to the wheel for any given speed. Lower ratios are generally desirable when going off-road. Higher ratios are better for freeway driving since they run at lower RPM's and offer better fuel economy. Changing tire size affects the final drive ratio. Switching from a 30" tire to a 35" tire changes the final drive ratio by about 17%. This may drop the engine out of its' "power band" and result in poor performance and fuel economy. To restore performance you must change the gear ratio to compensate for the change in tire size. If you originally had 3.07 gears you need a ratio that is approximately 17% lower, such as 3.55. If you want to increase off road performance you might want a 4.10 or lower ratio.