What's the difference between using 3.42 and 3.73 rear end gear ratios?

Question

I'm building up my 2003 S-10. it has the VORTEC V-6 with the 4 speed automatic transmission. I'm looking into both TransGO and B&M shift kits and a Wynjammer supercharger. I've already begun upgrading my exhaust to a true duel with high flow cats, 2 1/2" pipe and Flowtech "REDHOTS" glasspacks. No headers because the increase in HP DOES NOT warrant the cost. I plan on installing a pair of Lakewood traction bars during my next oil change/tire rotation. i REALLY want to make it hook up and would rather do the rear before installing the supercharger. Rear end gear ratios have always been a bit fuzzy to me. I would like to know the benefits of both so that i could make a really informed decision.

Answer 1

Seether, My bone stock 4.3, 262 incher 98 S-10 four wheel drive Chevy came from GM with 3.73 gears. I've driven it from NY to NC and back and nailed down 23.8 mpg. In a nut shell the drive shaft turns 3.73 times more rotations than do the rear axles in one revolution. When ever in doubt concerning final drive ring and pinion gears divide the gear teeth of the smaller pinion into the larger ring gear. With 3.73's your motor with a decent roller camshaft (standard and Chevy has others) the motor will push that truck well over 125 mph easily. If you are serious about the supercharger you'll be packing more air into the cylinders and a good set of headers is the only way to get the exhaust out efficiently.

Go to a car junk yard and pull off a front anti-roll bar from a Chevy Blazer of the same year. Buy new sway bar frame grommets at your Chevy dealer and install the fatter front sway bar. What a difference! Much flatter cornering. You'll have fun picking out wheels and tires to hook all the power up. Be careful of the wheel off-set as you don't want to spray rocks and mud all over the side of your truck.

Answer 2

It's just a V6. You don't need dual pipes except for looks. Summit Racing has an X-pipe if you want to get a good sound.

rear gear ratios mean the drive shaft turns 3.42 times or 3.73 times per each revolution of the axle. use the higher number 3.73 for lower end power and the lower number 3.42 for a higher top speed. Course that also depends on the gear ratio of your tranny. The more power your engine has the less you need to have the low end power.

Instead of a V6 with super charger consider sticking a 350 V8 in the truck. Use the higher geared differential 3.42 (or higer)(2.73) and you won't have to worry about anybody catching you.

Answer 3

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RE:
What's the difference between using 3.42 and 3.73 rear end gear ratios?
I'm building up my 2003 S-10. it has the VORTEC V-6 with the 4 speed automatic transmission. I'm looking into both TransGO and B&M shift kits and a Wynjammer supercharger. I've already begun upgrading my exhaust to a true duel with high flow cats, 2 1/2" pipe and Flowtech...

Answer 4

The real fuzzy belongs to the tranny it'self. The high ratio first gear and mid ratio 2nd gear will forever fuzz this truck's true capabillity! Start with top-end wishes to define the over-all tone. If you wish to run with 'vettes you have to be realistic 'bout tranny selection. Anything other than a tried and true turbo 350 will dissapoint you. As far as supercharging that Vortec-You need to remain steadfast in the fact that a v-6 is a tourque monster to begin with. Supercharging it is like adding twice as many legs to an ant! I personally would begin with a 350 ratio rear gear and work my way to the 300 end of things. As you approach the 130mph mark I'd work on down force to keep the front-end steerable.

Answer 5

LOL if you put a supercharger on there you WILL need the headers. if you want it to hook up better start with a better rear end. Like changing to a posi. as for the rear end ratios, the 3:73's will get you out of the hole faster but comprimise top end. the 3:42's will be your better choice for all around driving. the higher the gear number the better you will come out of the hole. Look at a top fuel dragster, they are limited to the gear ratio but the tires grow taller to give them top end

Answer 6

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Either one could be faster It depends on the car and the engine. Say the engine has 200 horsepower at 5000rpm And say the cars aerodynamic drag and power train drag losses will take 200 horsepower to reach a top speed of 130 mph. Then whichever axle ratio is closest to 5000 @ 130 mph will be the fastest. If it reaches 5000 before 130 it will not reach 130 If it would reach 5000 after 130 it will never reach 130 or 5000rpm. The engine power peak and aero drag determine what axle ratio will be the fastest.

Answer 7

the easiest way to put it is the higher the number the the more torque you'll put to the tires but it also takes away from your top end also. in my opinion i would use the 3.73 rear gears, will give a good balance for your application.

Answer 8

The difference is almost !/4 turn of the drive shaft. 3.42 means that the drive shaft turns almost 3 and 1/2 turns of the drive shaft to one turn of the drive wheel... Same with the other??? 3.73 3 3/4 turns of the ..... ya know

Answer 9

3.42 Gear Ratio

Answer 10

get the headers,, best money you can spend!!

a lower gear ratio such as a 4.10 vs say a 3.42 = more off the line performance but less gas mileage.. reverse that for a hi ratio such as a 3.42 vs a 4.10... better mileage but less torque to pull the vehicle off the line.