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Old 12-08-2017, 01:47 AM
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Join Date: Nov 2015
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Default My GY6 Engine Dyno - Built, not bought! (with full DIY CNC computer control)



I think this is the best fitting forum section for this post, as this build project is in the spirit of methodically testing GY6 upgrades to verify what works (and what doesn't).

IN PROGRESS

I started building this dyno in 2012, before I knew anything about hydraulics, embedded electronics, or circuit board design. It's been a long project, and a deep learning experience. Although it's not done, this build is now at the point where competes with $20,000 turn-key small engine dynos at around 1/10th the price. Even with the low cost, it still beats them out on functionality and modern tech.

To be fair, there are already several GY6 shops with dynos that have tested GY6 engines. Most that I've seen have the DynoJet SD-12, or a similar inertia dyno (more on this below). Why don't they post much about their results? It's rare to see actual data from them. Search YouTube for "gy6 dyno", and you'll find only a couple interesting runs, but mostly incomplete teaser videos of GY6 scooters on a dyno apparently when they first setup the machine, but no numbers, charts, or other data published after they get familiar with the system. I believe it is because they're using the wrong type of dyno, and getting results that aren't relevant. This build is different, and I believe will help us get answers that others can't.

So what do I mean by that...? Well, most times when we think of a dyno, an inertia type comes to mind. You roll your vehicle up onto a machine (or mount your engine) in such a way that spins and accelerates a weighted drum as quickly as possible. As soon as you hit redline, the test is over. This only lasts between 20 to 30 seconds tops. That's good for measuring power if you only want to know how the engine runs in short bursts of acceleration at WOT on flat ground, but doesn't allow us to test engines the real way we all ride the 150's. There are all sorts of terrain scenarios to measure that an inertia dyno isn't capable of reproducing.

That's why I chose to create a hydraulic brake system over an inertia type. With a brake dyno, we can control and simulate all sorts of terrain and scenarios (even hill climbing) all in real time. We can test the engine and transmission's responses to varying loads, and even hold a steady RPM under high load for long duration to test for specific problems. This is awesome for reliability and longevity testing especially for developing new powerful big bore, stroker, and high-compression configurations.

If you'd asked me in 2012 how long it would take to build the dyno, I would have told you "2 months tops". That turned out to be somewhat true. The physical frame and hydraulics were all functional at that point, but capturing good data out of the machine (with no computing system for data acquisition) was difficult, near impossible.

"2 month" version of the dyno (no data acquisition system)



Rolling my own dyno computing system

A dyno is only as good as its data. Otherwise, it's just a fancy test stand. Dyno manufacturers wanted $3,000+ for a barebones data acquisition setup that I felt has very limited usefulness. Even with that price point, the technology is old and clunky. Given the awesome amount resources for learning about microchips and embedded engineering available these days (Arduino for example), developing a system myself for my exact needs was the obvious decision. This is what I ended up with (below).

On the left is the heart and brain of the system. Inside of the enclosure are all of the components to take readings from sensors, transmit data wirelessly to the operator's desktop for logging and graphing. I wanted to take this a step further and add stepper motors which will control our brake valve and engine throttle on the fly in real time. On the right are the stepper motors, driver, and power supply. This lays the groundwork for full CNC dyno control. And "one touch" automatic dyno runs executed according to pre-scripted testing routines, really helpful for Quality Control on our engine builds, and maybe even automated break-in runs for new engines before they ship. Install your new engine, and haul butt right away without worrying if you're breaking it in right. Everything you see here was less than $300, sourced from generic online parts stores. It's a way more robust system than the $3k yesteryear tech.

The green board itself was originally going to have a much more important role, but technology advances so fast that it's a bit outdated now and I'm just leaving it in for show. Back when I bought the green board, I didn't have a clue how to design electronic PCB's. I'm up to speed now with a lot of practice from developing NanoEFI boards over the last two years. At this point, the only thing of importance on the green circuit board is the $1.50 microchip it houses, and the built-in USB programmer module. The real intelligence and logic in this box is going to be on a completely custom circuit board that I'm designing from the ground up just for this project (more on that later).





This project is entirely funded by your orders.
YOU make this possible. Thanks for your support.
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Last edited by T@BD; 12-08-2017 at 02:11 AM.
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