gear ratios and torque

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I've answered this correctly once. You'll just not have it any other way. You lose no torque whatsoever with a gear change. You simply change the torque curve at the rear wheels. And like Rob said, you may not change a thing with a converter.

I can think of no real reason you would even need to know this information anyway.
 
We get your torque answer, The engines torque out put is a constant. gears don't reduce the engines torque output, gears are multipliers of FORCE aka work, got it. Rusty, you're a page behind on this thread, everyone here has moved on to the physics of how gears and converters can change and effect that work value. So you cant think of a reason for me to know this info, bfd. I'm getting the impression that just because you think that, everybody should. Check the ego.
 
cudaFS said:
We get your torque answer, The engines torque out put is a constant. gears don't reduce the engines torque output, gears are multipliers of FORCE aka work, got it. Rusty, you're a page behind on this thread, everyone here has moved on to the physics of how gears and converters can change and effect that work value. So you cant think of a reason for me to know this info, bfd. I'm getting the impression that just because you think that, everybody should. Check the ego.
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The gears do not lower torque output of anything. Ego? I'm trying to get you to understand something, Has nothing to do with ego. You stil think somehow gears reduce torque at the rear wheels. They don't. But fine. I'm out.
 
cudaFS said:
We get your torque answer, The engines torque out put is a constant. gears don't reduce the engines torque output, gears are multipliers of FORCE aka work, got it. Rusty, you're a page behind on this thread, everyone here has moved on to the physics of how gears and converters can change and effect that work value. So you cant think of a reason for me to know this info, bfd. I'm getting the impression that just because you think that, everybody should. Check the ego.
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Also, I never mentioned the engine's torque output. I've always referred to the rear tires in both discussions. You just assumed incorrectly. But again, you can do this without me.
 
.09907121 x 100% = 9.90712%. Looks right to me, but there are calculators on gear ratio with tire diameter and rpm for anything automotive at Wallace racing that are more applicable. Percentage ratio increase/decrease is usually used for determining parameters in fixed stationary drive systems or oftentimes bicycle gearing instead of automotive application.
 
Garrett Ellison said:
.09907121 x 100% = 9.90712%. Looks right to me, but there are calculators on gear ratio with tire diameter and rpm for anything automotive at Wallace racing that are more applicable. Percentage ratio increase/decrease is usually used for determining parameters in fixed stationary drive systems or oftentimes bicycle gearing instead of automotive application.
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Even still, it's a curve. To say you have an increase or decrease requires a fixed data point. For this example, you'd need "at what RPM" do we have X amount of torque with one gear versus X amount of torque with another gear at the same RPM. That's why I said what I did. You simply move the torque curve up or down in the RPM range depending on gear set. You cannot just look at the whole picture and say "this gear makes less torque than that one". That's incorrect and is the point I was trying to make. But my ego got in the way. Damn that thing.
 
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cudaFS said:
dont ask me, It looks legit, I think I'll rephrase my question, is there that much of a difference between the 3:23's and 3:55"s? I can use the money somewhere else in the project if it wont. The engine's going to have gobs of torque any way
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I see no advantage swapping 3.23 to 3.55 's. a waste of time and money. imo
3.23 - 3.91 or 4.10's than your talking about torque magnification that will be noticeable in the rpm curve.
 
RustyRatRod said:
The gears do not lower torque output of anything. Ego? I'm trying to get you to understand something, Has nothing to do with ego. You stil think somehow gears reduce torque at the rear wheels. They don't. But fine. I'm out.
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work and torque arent the same thing, torque affects work, more torque more work or applied force. torque is force applied in a circular motion, gears make their own torque, it takes torque to make the force (work) to turn the axles, a crankshaft makes torque, a steering wheel makes torque.
 
As Rusty noted, much more about the whole combination. Torque output of the engine over the rpm range having to be matched with gearing and the converter, part of the whole being only as good as the sum of the combination of the parts.
 
cudaFS said:
work and torque arent the same thing, torque affects work, more torque more work or applied force. torque is force applied in a circular motion, gears make their own torque, it takes torque to make the force (work) to turn the axles, a crankshaft makes torque, a steering wheel makes torque.
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LOL. Ok man. I give up.
 
RustyRatRod said:
Even still, it's a curve. To say you have an increase or decrease requires a fixed data point. For this example, you'd need "at what RPM" do we have X amount of torque with one gear versus X amount of torque with another gear at the same RPM. That's why I said what I did. You simply move the torque curve up or down in the RPM range depending on gear set. You cannot just look at the whole picture and say "this gear makes less torque than that one". That's incorrect and is the point I was trying to make. But my ego got in the way. Damn that thing.
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Garrett Ellison said:
As Rusty noted, much more about the whole combination. Torque output of the engine over the rpm range having to be matched with gearing and the converter, part of the whole being only as good as the sum of the combination of the parts.
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ok f
 
bottom line here is, a 4.10 gear won't make a stock 318 faster, just makes it done quicker. much quicker
 
RustyRatRod said:
Even still, it's a curve. To say you have an increase or decrease requires a fixed data point. For this example, you'd need "at what RPM" do we have X amount of torque with one gear versus X amount of torque with another gear at the same RPM. That's why I said what I did. You simply move the torque curve up or down in the RPM range depending on gear set. You cannot just look at the whole picture and say "this gear makes less torque than that one". That's incorrect and is the point I was trying to make. But my ego got in the way. Damn that thing.
Click to expand...

RustyRatRod said:
Even still, it's a curve. To say you have an increase or decrease requires a fixed data point. For this example, you'd need "at what RPM" do we have X amount of torque with one gear versus X amount of torque with another gear at the same RPM. That's why I said what I did. You simply move the torque curve up or down in the RPM range depending on gear set. You cannot just look at the whole picture and say "this gear makes less torque than that one". That's incorrect and is the point I was trying to make. But my ego got in the way. Damn that thing.
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your smart *** answer, ego ...I can think of no real reason you would even need to know this information anyway. for what possible reason do you care why I want to know this? it has no bearing on anything wth ...I can think of no real reason you would even need to know this information anyway.
 
I wouldn't spend the cash on THAT gear change. Not saying i wouldn't change the gear just not the small change your looking at.

First decide at what speed you want to be at what RPM. Think long and hard about what you want the car to do and what you are gonna do with the car.

Run the numbers on the calculator, buy the gears, install gears.

Easy peasy.

For what its worth, most folks seem to go 3.73 for a hot street car car.
 
If you have a preponderance of torque, then the final drive difference of 10% is not a big deal, choose whatever best fits your needs.
but in second gear at 4400 rpm, my lil 367 be wanting the 3.55s, I mean 10% is still 10% .
If you swapped in 3.55s for the 3.23s and then your rpm is gonna go up 10% everywhere in the mph band,as compared to a particular mph number before and after. What I mean is if at 30 mph with 3.23s and in 2.45 first gear, your rpm is 2950; then with 3.55s it will be ~3250. So right away your engine is 300rpm further up the torque curve. Lets say you had a 2600TC, so stall-rpm is outta the picture. So if you had an engine like this; see below, an extrapolating the torque curve downwards from 3300 (to ignore the anomaly), lets say at 2950 the engine had 145 footpounds compared to 165@3250. So at 30 mph, you are 20#s ahead of the game with 3.55s, strictly by being higher up on the torque curve. Of course your engine will always be further up the curve at every mph, not just at 30.
This "phenomenon" is especially useful when climbing up the curve and going down the backside. And even more so if your combo falls off the cam at the top, like a lead-sinker.

land_dyno.jpg
 
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fishmens67 said:
bottom line here is, a 4.10 gear won't make a stock 318 faster, just makes it done quicker. much quicker
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yes! that's all Im asking. for the sake of argument, hypothetical, everything being equal, no variables, same rpm, same car, same size tires, same everything. is there much of difference between a ring and pinion of 3:23 ratio and 8 3/4 diameter vs a ring and pinion of 3:55 ratio and 8 3/4 diameter? for rusty's benefit...the reason I need to know this information is whether to change my 3:23's to 3:55's. I happen to like to know how things work, the physics behind how they work, what might improve or detract from the results of how they work. ( things that keep me up at night...how do bees fly without wings with built in lift?) I like quantifiable information vs anecdotal. My apologies for over complicating things.
 
Cope said:
I wouldn't spend the cash on THAT gear change. Not saying i wouldn't change the gear just not the small change your looking at.

First decide at what speed you want to be at what RPM. Think long and hard about what you want the car to do and what you are gonna do with the car.

Run the numbers on the calculator, buy the gears, install gears.

Easy peasy.

For what its worth, most folks seem to go 3.73 for a hot street car car.
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thats all I'm asking, thank you, read my other reply and it explains it all
 
Now let's talk about TM (Torque Multiplication)
For a streeter (all I know)
Lets say you had those 3.23s and 145#@30mph which being 2950rpm.
And lets say you had 27" tires. So then ftpounds to the road would be
145x2.45x3.23x24/27=1020# on the tarmac, multiplied by whatever the TC is doing.
And with the 3.55s? At 30mph we had 165# @3250 so;
165x2.45x3.55x24/27=1276# to the road... and
1276/1020= plus25% !
So if you had a 273 cuber this would be a really big deal. With a smogger-teen still a big deal. But by the time you get to a hi-torque 360, it is still spinning the tires @30mph so it means almost nothing.
But when you get into second gear and the spinning stops; that 25% is now adding up to be very important, to a streeter.
But two things are happening in second;
Firstly the torque curve is flattening out so your 25% advantage is constantly decreasing; take another look at that curve; from 4400 to 5100 the torque curve is pretty flat there, so when you are powering thru there, your advantage would drop to the 10% gear advantage. So for a streeter this could still be pretty important, but for a drag-racer not so much. And then on the downside the torque advantage is again increasing.
So, bottomline is anytime you are on the steeply rising/falling parts of the torque curve, the 3.55s are doubly helping you, whereas on the flat part, only the 10% gear advantage makes it thru.
And finally, if you can spin your tires to the speed limit with 2.76s, well, then this conversation is meaningless,lol.

Ok but let's not lose sight of the big picture.
In a streeter, 60mph is 5900 with 3.23s in first gear. And 6500 with 3.55s; if you have to shift, the 3.23s could get to the stripe first. It kindof depends on the combo.
 
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AJ/FormS said:
If you have a preponderance of torque, then the final drive difference of 10% is not a big deal, choose whatever best fits your needs.
but in second gear at 4400 rpm, my lil 367 be wanting the 3.55s, I mean 10% is still 10% .
If you swapped in 3.55s for the 3.23s and then your rpm is gonna go up 10% everywhere in the mph band,as compared to a particular mph number before and after. What I mean is if at 30 mph with 3.23s and in 2.45 first gear, your rpm is 2950; then with 3.55s it will be ~3250. So right away your engine is 300rpm further up the torque curve. Lets say you had a 2600TC, so stall-rpm is outta the picture. So if you had an engine like this; see below, an extrapolating the torque curve downwards from 3300 (to ignore the anomaly), lets say at 2950 the engine had 145 footpounds compared to 165@3250. So at 30 mph, you are 20#s ahead of the game with 3.55s, strictly by being higher up on the torque curve. Of course your engine will always be further up the curve at every mph, not just at 30.
This "phenomenon" is especially useful when climbing up the curve and going down the backside. And even more so if your combo falls off the cam at the top, like a lead-sinker.

View attachment 1715362966
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I thought the same thing, 10% insnt squat, I just need the math to prove it wasnt anecdotal, anecdotal most of the time equals talking out the *** , thank you for the graph
 
Oooo!
Im super down to discuss the lifting affects of a bees wing!

But maybe this is not the thread for it?

This is not a joke. I love the physics of flight.
 
cudaFS said:
your smart *** answer, ego ...I can think of no real reason you would even need to know this information anyway. for what possible reason do you care why I want to know this? it has no bearing on anything wth ...I can think of no real reason you would even need to know this information anyway.
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I wasn't being smartass at all. I was being dead serious. I was hoping maybe you would enlighten us and maybe share some knowledge of what you actually wanted to accomplish. There was no attitude involved whatsoever. We're surely getting from you.
 
cudaFS said:
I thought the same thing, 10% insnt squat, I just need the math to prove it wasnt anecdotal, anecdotal most of the time equals talking out the *** , thank you for the graph
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although 10% of 535
RustyRatRod said:
I wasn't being smartass at all. I was being dead serious. I was hoping maybe you would enlighten us and maybe share some knowledge of what you actually wanted to accomplish. There was no attitude involved whatsoever. We're surely getting from you.
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I'm holding your feet to the fire rusty, re-read your comment, you don't get to throw out insults then play the victim.
 
Cope said:
Oooo!
Im super down to discuss the lifting affects of a bees wing!

But maybe this is not the thread for it?

This is not a joke. I love the physics of flight.
Click to expand...
see you get it ! lol. use vision, creativity and see the bigger picture, then reverse engineer it to find how it came to be. That's my problem, I reverse engineer everything
 
cudaFS said:
although 10% of 535

I'm holding your feet to the fire rusty, re-read your comment, you don't get to throw out insults then play the victim.
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I insulted no one. You completely misunderstood me. Nobody's playing victim. I'm telling you how I meant something. You're trying to apply something to another thing that does not work. Since RPM is never the same in an automotive application, it doesn't work like that. It's almost as if you want to apply some kind of electric motor rules here. That's not the same thing.

But I answered your question as if it were in one of my posts. I said that if you wanted to know if a gear diminished torque at a specific RPM, then certainly with that fixed data point, you could figure that out. You're too busy trying to be offended over nothing to even read what I posted. I'll answer even further. I wouldn't swap from a 3.23 to a 3.55 for love nor money. There's not enough change involved. At least for ME.
 
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