FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Autoholic on December 29, 2015, 09:52:56 PM
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I decided the best way to do this would be to share the excel sheet I created. I don't know of any forum supported document hosting per users, so I have uploaded the file to my Google Drive. You can view and download the document at this link below. You will need to download it in order to use it. I have protected the sheet in order to prevent accidental deletion of any equations. Boxes in green are where user input is required. I should note that the RPM after the shift and the percentage after the shift is information about shifting from the previous gear. So for second gear, the RPM after the shift is the RPM in second gear after shifting from first to second.
Gear Calculator (https://drive.google.com/file/d/0B3iyR3ENvnVsTTdkQ2ZZenFkTlk/view?usp=sharing)
I have a few things to share and say about this excel sheet...
1. USE AT YOUR OWN RISK. While the math is accurate, I am not liable for any decisions you make involving my gear calculator. It's a tool to help you make decisions but it will not tell you the exact gear ratios you should use.
2. The higher the vehicle's max speed in a particular gear, the slower the car will accelerate in that gear. You'll need to factor this into your choices if you are using this calculator to help you determine a gear ratio or set of gears. What is your application, road coarse, drag strip or street?
3. The lower the vehicle's max speed in a particular gear, the faster the car will accelerate in that gear. You'll need to factor this into your choices if you are using this calculator to help you determine a gear ratio or set of gears. What is your application, road coarse, drag strip or street?
4. Having covered points 2 and 3, selecting gear ratios is a trade off between acceleration and top speed. If you didn't know this before hand, now you do. This is the reason why continuously variable transmissions are engineering wonders, theoretically you can have your cake and eat it too as long as you don't want to be able to shift the gears yourself. But where is the fun in that?
5. At higher speeds, aerodynamics will come into play and may prevent you from further accelerating. As long as the gears say you can go faster, just add more horsepower. Horsepower is how fast you hit the wall, torque is how far you take the wall with you.
Enjoy and always remember to keep the shiny side up. :)
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If someone would like to sticky this, that would be helpful for anyone looking for a tool like this. :)
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Gdaddy.
It would help me the most if you could give me the vehicle's actual tire size that is on the sidewall. The calculator I've created allows you to put this size directly into it.
As for your problem, in 4th gear the ratio is 1.00, regardless of wide or close ratio for a 4 speed toploader. With a 3.00 final drive and 26" tires, I have your setup cruising at 70 at roughly 2710 RPMs. At 75 MPH, you'll be about 2910 RPMs. So just below 3000 RPMs for 70 - 75 MPH cruising. Pay closer attention to it the next time you're on the freeway and see if the tach does read these numbers or is a little high. If it is high, maybe the forum will be able to help you fix it without replacing the tach.
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thank you , will do
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oh boy , I like playing with that , something else to keep me in this chair , got to get my rear in gear .
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Some info for anyone with a 4 speed toploader...
Close Ratio Gears...
First - 2.32
Second - 1.69
Third - 1.29
Forth - 1.00
Wide Ratio Gears...
First - 2.78
Second - 1.93
Third - 1.36
Forth - 1.00
Put "0" or a "-" in for fifth and sixth when using the calculator for a 4 speed. You'll end up getting errors in these rows, which is fine. The equations will still work once you put a 6 speed into the calculator. I like to use the "-" because it makes the whole row stop working, where 0 will still allow two columns to work.
Personally, when I'm looking at what makes a good gear combo, I look at the percentage of RPM drop after the shift and the RPM after the shift. If I have an idea of where the torque peak will be, I want to get the RPM after the shift to be maybe 500-1000 RPM below that. If I can have this as a consistent spot for each of the gears, the performance of the car will now be predictable. It will pull hard in every gear and I'll have roughly the same amount of time in each gear assuming I'm constantly accelerating.
I can add a row for reverse but typically it's the same ratio as first.
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The ratios you listed for toploaders seem different than I understand. I thought they were as follows-
Close ratio: 2.32, 1.69, 1.29, 1.00
Wide ratio: 2.78, 1.93, 1.36, 1.00
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The ratios you listed for toploaders seem different than I understand. I thought they were as follows-
Close ratio: 2.32, 1.69, 1.29, 1.00
Wide ratio: 2.78, 1.93, 1.36, 1.00
I concur.
My Top Loaders have even wider gear ratio sets. ;)
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This is my source for the gear ratios. There very well could be others.
http://www.davidkeetoploaders.com/torqueandgear.htm
Looking around, here are other sources for gear ratio information on toploaders.
http://www.5speeds.com/toploader.html
https://en.wikipedia.org/wiki/Ford_Toploader_transmission
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Kee's site is correct, but you have typo's.
In your wide ratio list. You have the same numbers for the wide as the close.
It's all good.
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That wiki TL site has some typo's also.
The case is about 10" so all the other lengths they are stating are not correct.
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check this out http://www.wallaceracing.com/Calculators.htm
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check this out http://www.wallaceracing.com/Calculators.htm
Love that place.
I can make the car do all kinds of things in fantasy land. ::)
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check this out http://www.wallaceracing.com/Calculators.htm
Yep, I've used that site for various engine calculations. There are a few other sites I've used. I haven't found any online calculators that combine the amount of info in my calculator for the purpose of gear ratios, rpms and velocity.
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Bump for anyone needing this tool.
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Bump for anyone needing this tool.
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so this year for beaver I changed the rear from a 3.00 to a 3.89. Changed nothing else on the car. Thought I would pick up .2 or .3 Nada, nope, nothing. The car was ever so slightly quicker on 60' & gave me a better reaction time, but by 1000' it was dead even with the 3.00s & et & mph was the exact same as last year. So I guess the only way to go faster is add horsepower or reduce weight. It is more fun on the street, & strangely enough, the MPG hasn't changed much.
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Shady, I'd check your whole setup with my calculator and see if things still made sense or were way off. Your vehicle should be able to meet the speeds listed for a given RPM, until you really start going fast. If what my calculator says your car should be able to do and reality is vastly different, I'd be interested in knowing the specs on your car. The most interesting thing about theoretical predictions and reality when it comes to cars is that of tires. Tires can be the reason why a setup just doesn't work.