Best advice. 
what do gears do?
Thread Starter
Intermediate
Joined: Nov 2006
Posts: 33
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From: Jacksonville Florida
what do gears do?
I'm kind of new to cars and am wondering what replacing the gears will do. I have an '05 Z51 and was reading that a guy was putting in 4.10 gears? What will this do? And what gears do I currently have? Does it cause the engine to rev quicker? Because I've noticed that the corvette engine takes a long time to rev, whereas a Ferrari sounds like a motorcycle when you rev the engine it spools up so quickly.
Le Mans Master
Joined: Nov 2004
Posts: 6,566
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From: Goleta CA
Cruise-In VIII Veteran
Well I'm sure you know the difference between being in a lower gear like second gear vs. third. Well changing the final drive ratio makes all the gears a little bit lower. Under load the engine will rev up quicker, but that's mainly because when you hit redline you'll be at a lower speed than before.
Short answer: It causes bigger smiles.
Short answer: It causes bigger smiles.
Drifting
Joined: Jan 2006
Posts: 1,560
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From: FNDA Beach Florida
Gears
You can check out DTE's web site that does many rear ends not just gears but beefing them up
http://www.dynotech-eng.com/dte_06_ls2-m6_c6_diff.htm
Chuck Cow a vendor in here does them and or check for local places that are confirmed quality. On the left side of the forum screen has various performance places you can contact as well. I think 3:73 gears would be the max you would want for your needs from your post, but it will stuff you in the seat as all the gears now dropped down some in the mechanical advantage giving the feel of more power when all you did was determine how that power is transferred to the rear tires. One of the best bangs for the buck. You should really consider the DTE or someone else mods that provide better shafts etc so no later down the line issues with broken parts. You only want that rear end coming out once. That is my nickel.
http://www.dynotech-eng.com/dte_06_ls2-m6_c6_diff.htm
Chuck Cow a vendor in here does them and or check for local places that are confirmed quality. On the left side of the forum screen has various performance places you can contact as well. I think 3:73 gears would be the max you would want for your needs from your post, but it will stuff you in the seat as all the gears now dropped down some in the mechanical advantage giving the feel of more power when all you did was determine how that power is transferred to the rear tires. One of the best bangs for the buck. You should really consider the DTE or someone else mods that provide better shafts etc so no later down the line issues with broken parts. You only want that rear end coming out once. That is my nickel.
Former Vendor
Joined: Nov 2005
Posts: 11,792
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From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
Give me a call and I'll try to answer your questions....
I'm kind of new to cars and am wondering what replacing the gears will do. I have an '05 Z51 and was reading that a guy was putting in 4.10 gears? What will this do? And what gears do I currently have? Does it cause the engine to rev quicker? Because I've noticed that the corvette engine takes a long time to rev, whereas a Ferrari sounds like a motorcycle when you rev the engine it spools up so quickly.
Chuck CoW
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Race Director
Joined: Dec 2005
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From: Carlsbad Ca
I'm kind of new to cars and am wondering what replacing the gears will do. I have an '05 Z51 and was reading that a guy was putting in 4.10 gears? What will this do? And what gears do I currently have? Does it cause the engine to rev quicker? Because I've noticed that the corvette engine takes a long time to rev, whereas a Ferrari sounds like a motorcycle when you rev the engine it spools up so quickly.
1. Gears transfer torque (force) from one shaft to another.
2. These shafts can be the same diameter.
3. These shafts can be different diameters.
4. These shafts can be in different directions.
5. Gears can take an amazing amout of torque,but they have to be spinning...and spinning fast.
6. Perfectly mated straight cut (wet) gears lose about 6% due to sliding on the tooth surfaces.
7. Torque loses are more when they are helical.
8. Torque loses are more when they are worn.
9. Torque loses are more when they are hypoid gears.
You ask about "rpm spool-up" also. This is caused by a "heavy" vs. "light" crank/recipro weight. (Providing fuel, and delivery systems notwithstanding.)
Since you are asking about rearend gears, a ratio with a higher # will have a better mechanical advantage to change speeds. This will also cause the "steps" between gears to be closer. (Making for more shifts to acquire the same speed as with the lower #.)
A higher # ratio will cause the engine to spin faster, therefor wear out at a faster rate.
Pro
Joined: Feb 2006
Posts: 632
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From: KINGS PARK NY
I'm kind of new to cars and am wondering what replacing the gears will do. I have an '05 Z51 and was reading that a guy was putting in 4.10 gears? What will this do? And what gears do I currently have? Does it cause the engine to rev quicker? Because I've noticed that the corvette engine takes a long time to rev, whereas a Ferrari sounds like a motorcycle when you rev the engine it spools up so quickly.
Safety Car
Joined: Dec 2005
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From: North Carolina
St. Jude Donor '07-'08-'09-'11-'12
Of course, with the new found fun, you do burn a bit more cause your foot gets heavier more often...
Tech Contributor
Joined: Mar 2003
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
One thing people never seem to mention about gears is that the rear tires are spinning slower in each gear meaning that if you do break traction, the car will accelerate to the speed of the tire faster and re-hook sooner than if you broke loose with 3.42's. To illustrate this:
In first gear at 5000rpm if you broke loose, the car would have to hit 40mph before the tire rotation speed and car's actual speed match. If you had 4.10's and were spinning tires at 5000 then it is about 32mph before you hook.....20% sooner. You hold the rpm's on a launch and punch it upon hooking. At a constant rpm the car eventually has to hit the MPH that the tires are spinning at.
While it breaks traction sooner, it regains it sooner. If you feel that you have no traction, adding more engine power and keeping 3.42's is the worst thing you can do. Get the gears and stop adding power when you cant get it to the ground anymore.
Last edited by SpinMonster; Jan 29, 2007 at 09:54 AM.
Instructor
Joined: Mar 2006
Posts: 247
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From: Clarksville Maryland
I understand that people like the mod, and I think I understand what a higher final gear ratio does mechanically, but my question is what does it do from a rolling start? My impression is that its a great mod for off the line acceleration, and that it makes 6th gear usable at speeds of less than 70 mph.
However, if I am on the interstate (or the track for that matter), will it help me pass the guy in front of me? The engine isn't putting out any more power. I can always control rpms from gear selection, and presumably whatever gear I am in, I am turning over at about 3-4K rpms. In other words, it's a great 0-60 mod, but what kind of 60-120 mod is it?
However, if I am on the interstate (or the track for that matter), will it help me pass the guy in front of me? The engine isn't putting out any more power. I can always control rpms from gear selection, and presumably whatever gear I am in, I am turning over at about 3-4K rpms. In other words, it's a great 0-60 mod, but what kind of 60-120 mod is it?
Former Vendor
Joined: Nov 2005
Posts: 11,792
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From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
Not exactly.......
I understand that people like the mod, and I think I understand what a higher final gear ratio does mechanically, but my question is what does it do from a rolling start? My impression is that its a great mod for off the line acceleration, and that it makes 6th gear usable at speeds of less than 70 mph.
However, if I am on the interstate (or the track for that matter), will it help me pass the guy in front of me? The engine isn't putting out any more power. I can always control rpms from gear selection, and presumably whatever gear I am in, I am turning over at about 3-4K rpms. In other words, it's a great 0-60 mod, but what kind of 60-120 mod is it?
However, if I am on the interstate (or the track for that matter), will it help me pass the guy in front of me? The engine isn't putting out any more power. I can always control rpms from gear selection, and presumably whatever gear I am in, I am turning over at about 3-4K rpms. In other words, it's a great 0-60 mod, but what kind of 60-120 mod is it?
They make the engine accelerate QUICKER and EASIER (smoother) under less load....
If I put a backpack on your back with 50 lbs of rocks...and ask you to climb a set of stairs as fast as possible.......
How much faster would you expect to climb the stairs without the bag of rocks on your back???
Trying to accelerate ANYWHERE with 3.42's or less....is like having 500 lbs of rocks in your trunk.....The engine will lug and accelerate slowly....
Dump the rocks (ie. install 4.10's
) out of your trunk....how quickly do you think the RPM's are gonna come up? And how much faster do you think the vehicle is gonna be????That's the best way I can explain it.....
From a dead start.....from a roll.....on the highway......You can't beat it.
Chuck CoW
Instructor
Joined: Mar 2006
Posts: 247
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From: Clarksville Maryland
Chuck;
I don't know if I like your analogy. I understand if I lighten the car it will go faster, but gears don't lighten the car.
If you use the example of a bicycle, the 4.10s are like the front sprocket. If you pedal using only the smaller front sprocket, you will take off faster than if the chain is on the bigger sprocket. Now I may be off, but my experience with riding bikes is that if I am riding along pretty fast in the smaller sprocket on the front (the 4.10) and the rear sprocket is in say 4th, it isn't that much different than riding along in the bigger sprocket on the front and being in second gear on the rear sprocket.
The bike weighs the same, my legs are the same, and the gearing at speed with the larger front sprocket (3.43) can be offset by the lower gear on the rear, while using the smaller front sprocket (4.10) can be increased by using a higher sprocket on the rear.
Anyone have a SOTP impression of the difference in roll on acceleration with 3.90s or 4.10s?
I don't know if I like your analogy. I understand if I lighten the car it will go faster, but gears don't lighten the car.
If you use the example of a bicycle, the 4.10s are like the front sprocket. If you pedal using only the smaller front sprocket, you will take off faster than if the chain is on the bigger sprocket. Now I may be off, but my experience with riding bikes is that if I am riding along pretty fast in the smaller sprocket on the front (the 4.10) and the rear sprocket is in say 4th, it isn't that much different than riding along in the bigger sprocket on the front and being in second gear on the rear sprocket.
The bike weighs the same, my legs are the same, and the gearing at speed with the larger front sprocket (3.43) can be offset by the lower gear on the rear, while using the smaller front sprocket (4.10) can be increased by using a higher sprocket on the rear.
Anyone have a SOTP impression of the difference in roll on acceleration with 3.90s or 4.10s?
Last edited by JD21029; Jan 30, 2007 at 05:29 PM. Reason: typos
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
I'll agree with you...........
Chuck;
I don't know if I like your analogy. I understand if I lighten the car it will go faster, but gears don't lighten the car.
if you use the example of a bicycle, the 4.10s are like the front sprocket. If you pedal using only the smaller sprocket, you will take off faster than if the chain is on the bigger sprocket. Now I may be off, but my experience with riding bikes is that if I am riding along pretty fast in the smaller sprocket (the 4.10) and shift the rear sprocket from say 3rd to 4th, it isn't that much different than riding along in the bigger sprocket and being in second gear on the rear sprocket.
The bike weighs the same, my legs are the same, and the gearing at speed with the larger srocket (3.43) can be offset by the lower gear on the rear, while using the smaller sprocket (4.10) can be increased by using a higher sprocket on the rear.
Anyone have a SOTP impression of the difference in roll on acceleration with 3.90s or 4.10s?
I don't know if I like your analogy. I understand if I lighten the car it will go faster, but gears don't lighten the car.
if you use the example of a bicycle, the 4.10s are like the front sprocket. If you pedal using only the smaller sprocket, you will take off faster than if the chain is on the bigger sprocket. Now I may be off, but my experience with riding bikes is that if I am riding along pretty fast in the smaller sprocket (the 4.10) and shift the rear sprocket from say 3rd to 4th, it isn't that much different than riding along in the bigger sprocket and being in second gear on the rear sprocket.
The bike weighs the same, my legs are the same, and the gearing at speed with the larger srocket (3.43) can be offset by the lower gear on the rear, while using the smaller sprocket (4.10) can be increased by using a higher sprocket on the rear.
Anyone have a SOTP impression of the difference in roll on acceleration with 3.90s or 4.10s?
I'm not trying to get scientific here...Just making a generalization... But, I agree with you....I've used the 10 SPEED BIKE analogy before myself.....
Starting off from a dead stop in 5th speed on a 10 speed bike is like taking off with 3.42's or so.....
Starting off in FIRST on a 10 speed bike is EASIER on the driver (less load... no rocks in your pocket....
) You will pedal FASTER, but EASIER......and you will accelerate more quickly.....I used the same example in a REAR END post a week or two ago....
GOOD EXAMPLE
Chuck CoW
My wife is the only one who touches my rear end.