spaz1

iTrader: (9)

I don't think it makes any differnce as long as the gear ratio is the same. I think you would actually loose a bit of power to the wheels cause you have to turn a heavier gear set.

socmguy

iTrader: (18)

Have the mechanical engineers been consulted yet?

wrd1972

iTrader: (12)

A response from a mechanical engineer where I work.

There is no mechanical advantage from a (9" 4.10) R&P over a (10 bolt) 4.10 R&P. You can draw simple teater totters and fulcrum points on a white board to prove it.

Bottom line is if you have a V8, and put 1000RWHP to the ground and for discussion sake, pull a 1.5 sixty foot on drag slicks, the 9" will provide faster ET's than the 10 bolt because as we all know the 10 bolt will pop and the 9" will stay together and get more torque to the ground.

If you take the same car and remove the V8 and install a 10RWHP Briggs and Stratton lawn mower motor, the ET's would be faster with the 10 bolt as compared to the 9" because it takes more energy to turn the bigger, heavier and less efficient 9" gears. And your ET would be about 10 minutes.

TranzAmMan

I agree with wrd1972, there is no advantage from a 9in in 4.10 over a 7 5/8 (10 bolt) with a 4.10. Sure the ring is bigger in the 9in, but the pinion is also bigger. If the pinion was the same size as the stock and you put a 9" 4.10 in, sure there is going to be a change but it is not going to be a 4.10 anymore its going to be larger (like a 4.50 or something w/o doing the math).

An example that I can think of is a bicycle. Lets say you have a 36 tooth sprocket going to a 36 tooth sprocket. That is a 1:1 ratio. Just because you switch to a 48 tooth sprocket going to a 48 tooth sprocket (1:1) doesn't mean anything is going to change (assuming the weight of the 2 sets of sprockets are the same).

The reason why people see better numbers at the track is because there is more weight in the 9in than the 10 bolt which means more mass to get you off the line. This is the same reason why drag racers don't use aluminum flywheels since they bog down at the tree. Just my 2 cents, im not an engineer yet either.

R1ch

iTrader: (4)

I ran my friend's 3rd gen that's also an M6 and I have a 10 bolt with 3.42s and he has a 12 bolt with 4.10s.

He only made 10 more HP than me and only pulled like a car probably mainly because the 3rd gen is lighter.

If 4.10s in a 12 bolt are like 4.82s, shouldn't he have been out way further?

MeentSS02

iTrader: (11)

That's because it doesn't work that way with gears - the torque multiplication is from the ratio itself, not the size.

FirstYrLS1Z

iTrader: (4)

Thanks for all the responses and inputs,just because I saw something and deduced a thought from what I saw doesn't mean I was correct in my thought process.It's better to see the thread responses showing my deductive errors and not allow me to go off on some screwball tangent.
I've got to do that teater totter/fulcrum points/white board thing to find out how I screwed up.

spaz1

iTrader: (9)

driven/drive not really much to do with leaver action and such. It is linear x amount of turns in = x amount out. the size of the gears doesn't change, that is the way I see it. Mabe I'm wrong.

TranzAmMan

You may have been wrong but it made me think since I didn't know the answer at first. I love to think about these sorts of things.

Black01M6SS

iTrader: (3)

Wow, you thought way farther into it than most "normal" people would...

Hot m6 WS6

I don't quite think that is what he was explaining. Sure the overall ratio is the same, but the torque multiplication would be caused by a longer moment arm or lever, because the ring gear is physically a larger diameter. Think of it on a bike, the gear ratio will theoretically be the exact same, but the difference that is being proven would be like changing the length on the bicycle crank. A longer length from the center of the crank to the peddle would allow you to do more work (torque) with the same amount of power. Just because it is the same gear ratio, doesn't mean the moment arm or leverage on the gearset is the same. Thus, it makes it "feel" like a steeper gear. Think of it as putting a length of pipe on the end of a breaker bar. The breaker bar is a 1:1 ratio, but the pipe allows you to transfer much more torque. Your arm is moving the same speed, but the nut is turning slower than it would if your hand were to be closer. Know what I mean? I'm no mechanical engineer, just a drunken college kid on a thursty thursday.

bigredhelland

iTrader: (1)

It is as simple as this.

the larger gear has to move faster (in distance, not degrees) to keep the ratio the same.
the total amount of work done is the same.

ever use a cheater pipe on a wrench? yea you can easily break a stubborn bolt loose or even off but you have to move it a long ways to do the same amount of work that can be done in a short amount of time with a regular wrench (time meaning distnace moved/ work done). if you left the cheater pipe on all day your arms would be really tired by the time you got that one bolt off.

Yes you WILL have more LEVERAGE with a larger diameter gear, but that point of the gear has to move FARTHER (in degrees or distance) to turn the axle the same amount...

its all about the ratio number. the torque is multiplied by the ratio and ratio only. yes friction and mass and momentum can have slight effects on the comparrison but you will not put any more torque to the axles by changing rear ends without changing gear sets.

also... yes changing wheel tire combinations can have a similar effect to changing gears, because it changes the RATIO of the axle turning to the distance the car moves

make sense?

litemup02

iTrader: (39)

Yes it does... and in much simpler terms and using examples makes it easier for most of us..lol

Hot m6 WS6

You just proved the theory yourself, but I think you are confused. The fact that there is a larger distance from axle center (where you stated more leverage) and the fact that the gear has to move FARTHER in degrees or distance to turn the axle the same amount means that there is a multiplication of torque occuring. Leverage and torque are basically the same thing. I googled a link that explaines this basic theory better, because I don't know how to post pictures yet. Go here for what I mean...

http://www.akotorque.com/html/wit.html

TranzAmMan

Yes but changing the gears in the car does not change the input at all. The rear end is just two gears, thats it (keeping the innards out of this conversation). In the bike example, you cant change the bicycle crank length unless you change the input into the rear end (transmission, motor, transfer case, ect). My example still holds true, think of it like this instead of having the bicycle crank attached to the peddles, think of it having a drive shaft welded to the middle of the gear going to a motor. If you change the gear size 36:36 to 48:48 there will be no change.

Actually only in distance not degrees. Degrees will always be the same no matter what gear you have. All gears move 360 degrees.

I understand that you can create more leverage with a larger length but in your example there is only one variably that is being changed, the length of the torque arm. However when changing from 10bolt to 9in two things are changing, the ring AND pinion. There is two variables not just one, that is what people are overlooking.

I hope this is understandable.

Hot m6 WS6

I do understand what you are saying, and although the pinion is larger, It shouldn't take any effect on the fact that the ring gear is larger, causing more leverage action. Technically, the larger pinion gear has more leverage action on the ring gear, due to it's larger diameter also. All of this could mean slightly more rear wheel torque... but to be totally honest, the added weight of the larger gears and heavier housing would offset any gaines.

It's not like this difference would be noticable while driving the car, and the fact remaines that the only reason we switch to other housings is the added strength. I just want to make it clear that i am not saying It will change the way 4.10 gears feels in a 10 bolt vs. 4.10's in a 9", but it could allow slightly more torque multiplication to the axles, given the same ratio. This is a small enough measurement that the added weight of rotational mass in the 9" would more than offset the gaines, and we would probably see less power at the tire.. (more weight and friction).

I know that the ratio is the sole variable that will change wheel speed vs. driveshaft rpm. I know i wasn't very clear in what i was saying last night, and even this morning.. Sorry for that, we had a case race last night, and I wasn't at my optimum function levels if you know what I mean! haha

bigredhelland

iTrader: (1)

i think that maybe i confused my self, and possibly others with my examples. but i did think of this as well that might help clear up what i was trying to say.

so if the ring gear has a larger diameter, the pinion diameter must also be increased to accomodate for the larger teeth and spaces between the teeth on the ring gear. if the pinion was left untouched you would have created a different ratio all together.
to keep the gears all lining up nicely to avoid binding you would have to increse the number, or the size of the gears on the pinion and on the ring gears to keep things functioning. but if the ratio stays the same, so does the torque.

if you increased ONLY the size of the ring gear then YES you would have increased the ratio, or torque delivered, but since that is also changing the ratios it would never be a true comparison.

since the pinion is made larger to match up to the different size ring, total leverage is decreased (back to where it was at before) and the ratio stays the same as well as torque.

so in english the gears have to be matched to each other and there for the same ratio means the same torque output, every time.

Dirty 30

iTrader: (96)

On my window sticker it says 3.23 "performance" gear ratio and 3.42's dont say that. Why would it say "perfomance"?

FirstYrLS1Z

iTrader: (4)

3.23s' are the optional 'performance' upgrade from/over the standard 2.73s' that are supplied with automatics.3.42s' are the standard for 6speeds and there is no performance upgrade for 6 speeds.

TranzAmMan

That's Exactly what I was (or tried) to say