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Speed calculation

(@walter)
Member

Hi guys! i love how yourdyno is going up! i was wondering about to make easy for speedo calculation, i means, based on RPM and gear ratio, that can be calculate automatically once you put both values.. thank you!!

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Topic starter Posted : 20/01/2019 8:10 pm
(@amelia)
Member

Gear ratio is not needed, I think will be a easy calculation, if is a roller dyno would be dyno rpm x roller circumference, if is a hub dyno then the calculation is dyno hub rpm x wheel circunference.

Regards

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Posted : 20/01/2019 10:50 pm
(@bmgjet)
Dyno Wizard Moderator

Im not to sure what your question is?
There already is a plugin for giving you a speedo and logging distance traveled on the dyno. New version that supports plugins should be released soon.

If the purpose is you want to calibrate speedos then it wouldnt be hard to add a button in that plugin to stop the dyno going over a set speed so you can check the car vs dyno reading.

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Posted : 21/01/2019 6:24 am
(@walter)
Member

I have a hub dyno, yes, it's about Wheel diameter, ok ,diameter of hub adapter?, just that would be calculate for every car, does it? shouldnt be easy when it's gear ratio calculate for every car, automatically could be calculate speed setting?

 

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Topic starter Posted : 21/01/2019 9:18 am
(@amelia)
Member

In a hub dyno is not possible, you need to input each time the wheel circumference 

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Posted : 21/01/2019 10:40 am
(@walter)
Member

i thought it would be possible by calculation rpm+gear ratio.

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Topic starter Posted : 21/01/2019 11:26 am
(@amelia)
Member

Is not possible on a hub dyno, you know how many rpm the car have, but you don`t know what distance it moves for one turn

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Posted : 21/01/2019 2:45 pm
(@mach_1)
Member

 Can't you hold 5 to 10 kwatts of load steady state at 100km/h and note the engine RPM on your tachometer, doesnt matter what vehicle/motorbike and you get a ratio factor. That's the speed to RPM ratio for that specific vehicle/motorbikes you are testing. As you stated each vehicle/ motorbike will have different differential/tyre ratios and sizes.

A C# code  function window where you entre the dyno roller speed at 100km/hr ratio factor and the x-axis has road speed numbers and below them a corresponding  engine RPM.

Just my 2 cents worth.

But most accurate way is still picking up tacho signal so one can correlate at what engine horsepower verse RPM  rather than engine horsepower verse road speed

YourDyno is evolving nicely.

 

This post was modified 2 years ago by Mach_1
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Posted : 21/01/2019 9:52 pm
(@walter)
Member

Hi, ok! it's not very important, but looking it's possible to add to the dyno sheet would be great. Idk how dynpack calculate speed..maybe they use speed sensor instead rpm sensor.. 

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Topic starter Posted : 25/01/2019 8:17 am
(@bmgjet)
Dyno Wizard Moderator

Dynapack asks your wheel size and final drive. Then works it out for you. Also asks you for weight for the 1/4 mile functions and cruising stuff to hold a realistic light load.
Attached a screenshot of what it asks you on setup.

I could modify the speed/distance plugin to ask you for wheel size and final drive which would add the same function for hub dynos, I just dont have a hub dyno to test it on since mine is rolling road.
Thats if Jostein doesnt want to do it him self since its his plugin.

This post was modified 2 years ago 3 times by bmgjet
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Posted : 25/01/2019 8:54 am
(@walter)
Member

mm i see, just asked that since in my other roller dyno never put Wheel size for to see speed. was used with other DAQ though. but looks like with roller dyno should be easy than hub dyno. Thanks anyway!

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Topic starter Posted : 27/01/2019 7:28 pm
(@bmgjet)
Dyno Wizard Moderator

Rolling road you just need to know the roller size. Which is a constant so only setup once.

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Posted : 27/01/2019 9:18 pm
(@admin)
Member Admin

bmgjet, 

Go ahead and modify the speed plugin! Appreciated 🙂

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Posted : 01/02/2019 7:58 pm
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