Author Topic: What's it gonna take to build your own low cost dyno?  (Read 8558 times)

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Offline sandblaster

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What's it gonna take to build your own low cost dyno?
« on: November 15, 2014, 05:03:29 AM »
I started a thread here:
http://www.oem-cycle.com/forum/viewtopic.php?f=5&t=890&p=3438#p3438

But I figured that the more idea's we get the better.
So let's open this up...

So you think you made some cool mod on your scoot.
You take it out and run it down the road and the butt dyno say's "YEAH!!!!!"
But often times the butt dyno is extremely inaccurate.
So, lets examine building your own Dyno
What?
Sound scary?
Perhaps not as much as you might first think.
What does a dyno measure?
Work.
So imagine a big fly wheel with a known weight and diameter being driven and measuring how fast you can speed up that flywheel...
Here is one fellas example:

https://www.youtube.com/watch?v=ZQNVKyNYyIA
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #1 on: November 15, 2014, 05:09:50 AM »
Of course you could incorporate things like your engine RPM, Exhaust Gas temps, Water temps ect.
So let's start with the basics.
A steel frame, a heavy flywheel on pillow blocks, a way to strap your scoot down, a trigger for measuring the flywheel speed, engine rpm, and how to capture that data on your lap top.
And how about some ventilation   :-o
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #2 on: November 15, 2014, 05:14:08 AM »
Oh... and some safety gear...
Fire extinguisher, ear protection, decking to cover most of the flywheel.... What else???
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #3 on: November 15, 2014, 05:43:42 AM »
Interesting site.
I will be looking at it closely later today...

http://www.land-and-sea.com/do-it-yourself/diy-plans.htm
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline tobys 2 strokes

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Re: What's it gonna take to build your own low cost dyno?
« Reply #4 on: November 15, 2014, 05:46:24 AM »
I got to spend a day in Dave Roberts shop (ILR performance) with my tecate 330 on his Dyno. its a Land and Sea dyno.

it measures it at the crank.
I think you could make somthing simular with a hyd pump and valves and pressure sensors
« Last Edit: November 15, 2014, 05:50:55 AM by sandblaster »

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #5 on: November 15, 2014, 06:00:47 AM »
That's cool.
What kind of results did you get?

For me, (Cause I'm simple) I'd rather measure at the rear wheel for a couple of reasons.
I don't want to pull my engine every time I want to do a dyno run.
Something as simple as a different chain and sprocket set will change effect your rear wheel HP.
And it seems like it would be difficult to calibrate and maintain calibration of the fluid type dyno's.
I need simple.....
But let's discuss it...
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Dutch-K5 Fan

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Re: What's it gonna take to build your own low cost dyno?
« Reply #6 on: November 15, 2014, 06:21:26 AM »
Whant one for my sellf like so many things :-D

http://www.hpi.be/dyno.php

Maybe this could work?


Dutchie
Proud owner of a KX500AF

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #7 on: November 15, 2014, 06:28:04 AM »
Thanks for the link Dutchie...
You should buy it and let us know how it works  :-D
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Dutch-K5 Fan

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Re: What's it gonna take to build your own low cost dyno?
« Reply #8 on: November 15, 2014, 08:57:54 AM »
Can we go Dutch with splitting the cost :lol:



Dutchie :mrgreen:
Proud owner of a KX500AF

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #9 on: November 15, 2014, 10:58:54 AM »
I'd like that but it would be a long drive for you to get here to use your half :-)
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #10 on: November 15, 2014, 11:00:01 AM »
Crofter985

This is the Australian web page I mentioned in the other thread.

http://dtec.net.au/index.htm

For a 1000 bucks Australian you get the hardware and software just supply your own flywheel
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline 1901306708

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Re: What's it gonna take to build your own low cost dyno?
« Reply #11 on: November 15, 2014, 03:04:59 PM »
the land and seas are allright. the strain sensor failed often on the one i was around.

what works good is if you take the power off your front sprocket. take an old sprocket and weld a ~4 in long piece of pipe onto it. use a large enough ID to get your snap ring pliers inside to attach it to your bike. on the other end of the piece of pipe, weld on a flange. weld the same flange onto a shaft going to your dyno and bob's your uncle. its nice to have a rubber dampnner in your system somewhere.

power varies alot with air temp, crankcase temp, coolant temp all sorts of things so consistancy is important.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #12 on: November 26, 2014, 02:53:01 AM »
Crofter985

Had a look on eBayUK last week and found this up for auction.



Put a bid on it at the start price and it ran for the three days it had left to run without being challenged.
It's a 330x400mm slug of steel, two sets of bearings, a disc, caliper and master cylinder, a starter ring and starter motor for said starter ring. Now there's a good few other bits to get but that's a good start. It's not all plain sailing as far as the rotor is concerned it's only big enough for 50hp but what I am thinking of doing is to get some discs of 50mm thick steel made up and fit them to the ends, or I've just had a thought, get another slug of steel the same size and make a double roller set up that the wheel sits in. There's a few interface box options, I will have to do some detailed research before I buy. Once I gave a roller setup working it will be possible to do comparative testing without electronics just by timing runs, probably not much use for any kind of accuracy, what it will be able to do is a quick dry and warm ( important factors in winter round here ) way of setting carb up, getting A/F ratios set up and so on.
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #13 on: November 26, 2014, 02:53:24 AM »
I've been contemplating this idea.
If I go through with it I want to make mine wide enough so that I can dyno Quads as well as bikes.
I don't even own a quad but as soon as people find out you have a dyno they will seek you out :D
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: What's it gonna take to build your own low cost dyno?
« Reply #14 on: November 21, 2015, 01:34:54 PM »
There's been some updates to this thread

http://www.oem-cycle.com/forum/viewtopic.php?f=5&t=890







The four stroke engine: That's one stroke for producing power and three for wearing the engine out.