Should I build a few of these dynos?

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Doinstuff

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Hey out there. After a bit of an argument with my buddy last fall I set out to build a small engine dyno so that I could prove myself right. One thing lead to the next, I overcomplicated things, and I spent the winter putting this thing together. I went through a lot of trial and error to get to this point, but am more or less happy with the results.

It has a touchscreen user interface. It is rated for 40 ft/lbs of torque, 40 horsepower, and 10,000 RPM. There are fun to watch gauges for torque, RPM, and horsepower while making runs in either the freestyle or timed run modes. Once finished with the run it can be graphed for a good visual representation of your power curve. The whole thing is powered by USB C, so it's portable. I power it off of my jump pack. I even learned to powder coat.

So, should I make more of these things, would anyone be interested? It doesn't have all of the bells and whistles, but will accurately tell you how much power you're making, where that power is RPM wise, and if that last mod you made helped or hurt, or was just a waste of time.

I got the bill of materials down enough that I could comfortably sell them for $999 shipped domestically. I think if that has been an option when I started this project I would have one, but maybe that's just me.3ed01e7c-2c3c-4441-9527-04e910efba00-1_all_940.jpg110.jpg82.jpg
 
Hellion

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HORY SHET, you may be onto something. I don't know enough about them and definitely didn't think they were portable. . . . . .🤯

Anyway, I am bumping your thread (to hopefully raise it above the current glut of garbage)
 
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Hellion said:
HORY SHET, you may be onto something. I don't know enough about them and definitely didn't think they were portable. . . . . .🤯

Anyway, I am bumping your thread (to hopefully raise it above the current glut of garbage)
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Thanks. Yeah, they aren't really very portable, until now.
 
Hellion

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Be very careful about sharing the technical details, or someone will (maybe) try to steal your invention.

EDIT: be patient with DIYGK, no one is minding the store and we are overrun with spammers and scammers
 
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Doinstuff

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Hellion said:
Be very careful about sharing the technical details, or someone will (maybe) try to steal your invention.

EDIT: be patient with DIYGK, no one is minding the store and we are overrun with spammers and scammers
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Honestly, I come from an open source background. Once everything is hammered out to my satisfaction I'll probably open source everything, bill of materials, CAD files, source code.

To write the software to the screen you need to have vscode installed and set up correctly for the device, it wasn't fun, go ahead, I encourage you. If you do that we can probably collaborate to make it better, bet you won't.

The bill of materials works out to just under $400:
$23 motor plate
$34 touchscreen ESP 8048S070
$3 HX711 load cell amplifier
$4 NJK 5002a hall effect sensor
$30 PSD S1 load cell 50kg
$11 UCF204 flange bearing X2
$16 MR16SS needle bearing
$12 IR1216 bearing race
$14 3/4" keyed shaft 9"
$17 brake hub for 3/4" shaft
$13 8" brake disk
$6 L095 Lovejoy spider
$17 L095 3/4" Lovejoy coupler X2
$25 hydraulic brake
$12 M12 rod ends X2
$26 3/8" 12"x16" lexan
$12 twist throttle
$50 1"x3"x14ga 100" rectangular tube
$12 3/16" plate 6"x12" X2
$6 7/8" OD round tube 12" length
$9 1/16" 15"x5.5" aluminum diamond plate
$27 1x3x10 aluminum torque arm
$4 electrical plugs
$15 misc fasteners

$398
A lot of those prices you'll only realize if buying in at least some level of bulk. For example, I just looked up the touchscreen. $47 for one when added to my eBay cart, $66 if you don't know the right keywords.

I figure I can probably ship it anywhere domestically for $100. So all told it cost me $500 to get one to you.

I'm pretty sure I can build one of these in 2 days after I've done a couple. I built a jig, I made templates for every piece I could. I'm still expecting an 8 hour day to cut, drill, weld, grind, and clean. I'm expecting another day to powder coat and assemble. On some level it almost isn't worth it.

I'd rather people build their own, or retrofit older units, and I'll help out on the electronics side. I have a hard time envisioning enough demand for it to be an idea worth stealing.

Truthfully, I will take you comment as a compliment, though. Thank you.
 
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Doinstuff

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Master Hack said:
That sukka is beyond cool! It is priced right as well! You should have no problem selling a bunch of them!
Denny is a undercover rep for comet belts....maybe, oh no, wait!
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Thanks for your words of encouragement. I was totally not sure when I was working on this what the response would be like. Support like that is much appreciated.
 
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ezcome-ezgo said:
Wait, you're going to work 8 hours a day for $100 profit? Did I read that correctly?
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Not quite, it would be 2 days of work for $500 profit. Not great, but I'd enjoy doing it, at least.

Edited after looking back:
I can see how you got that if you missed the $999 mentioned in the first post.
 
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Looks like a really good simple dyno you have there. I have a couple questions. Why did you not make the motor mount height adjustable? With up to 40hp testing available you could test big block series (GX390 on up) engines with an adjustable height engine mount. Also thumbing around your Github, why not give simple measurements (AKA prints) for the metal parts. I don't see any of those parts that couldn't be made in most home garages and not everyone has access to cnc equipment (sorry if it is there and I didn't see it). I would be all over building one of these but I know I'm not experienced enough to tackle the electronics part of it. Your price for selling complete units is not bad. If I were still into kart racing I'd buy one in a heartbeat. I just don't know if I'd use one enough to justify buying one now. Do you have any videos of this dyno in action? Please take all this has positive criticism.
 
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vpd66 said:
Looks like a really good simple dyno you have there. I have a couple questions. Why did you not make the motor mount height adjustable? With up to 40hp testing available you could test big block series (GX390 on up) engines with an adjustable height engine mount. Also thumbing around your Github, why not give simple measurements (AKA prints) for the metal parts. I don't see any of those parts that couldn't be made in most home garages and not everyone has access to cnc equipment (sorry if it is there and I didn't see it). I would be all over building one of these but I know I'm not experienced enough to tackle the electronics part of it. Your price for selling complete units is not bad. If I were still into kart racing I'd buy one in a heartbeat. I just don't know if I'd use one enough to justify buying one now. Do you have any videos of this dyno in action? Please take all this has positive criticism.
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It is as simple as it is mainly to keep costs down. Beyond that the whole machine would have to been bigger to make it work. I had thought about it, but decided against it. One could easily build a larger machine and retain all of the electronics software for larger engines.

As far as a set of prints go, it is all in the CAD file which was, for me, the easiest way to share that. There are 17 pieces of steel and a nut that get welded together to make the base. The CAD file includes those, along with all of the part numbers for electronics, the stl for the touchscreen case can be exported out for 3D printing, I just prefer the single file approach to housing all of that info.

It's kind of crazy, but as I was setting this all up this weekend I realized that I have exactly zero videos of it in action. I have a video of the build process, and one of powder coating one, but that's it. This week I'll make a couple and get them linked in some way.
 
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For some reason I was unable to open the CAD file. The Github said it can't show files that are that big right now???? Please put up the videos!!!
 
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Doinstuff

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vpd66 said:
Looks like a really good simple dyno you have there. I have a couple questions. Why did you not make the motor mount height adjustable? With up to 40hp testing available you could test big block series (GX390 on up) engines with an adjustable height engine mount. Also thumbing around your Github, why not give simple measurements (AKA prints) for the metal parts. I don't see any of those parts that couldn't be made in most home garages and not everyone has access to cnc equipment (sorry if it is there and I didn't see it). I would be all over building one of these but I know I'm not experienced enough to tackle the electronics part of it. Your price for selling complete units is not bad. If I were still into kart racing I'd buy one in a heartbeat. I just don't know if I'd use one enough to justify buying one now. Do you have any videos of this dyno in action? Please take all this has positive criticism.
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I neglected to respond to another little part of your post. The part where you said you'd do it if not for the electronics part. Before the end of the week I expect to have just the electronics for sale also. I have 20 or so of these screens. I want to put a couple together and pay attention to how much actual labor is involved before deciding on a price. So keep an eye out for that. I'm thinking somewhere between $200-$300.
 
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Doinstuff

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Doinstuff said:


I neglected to respond to another little part of your post. The part where you said you'd do it if not for the electronics part. Before the end of the week I expect to have just the electronics for sale also. I have 20 or so of these screens. I want to put a couple together and pay attention to how much actual labor is involved before deciding on a price. So keep an eye out for that. I'm thinking somewhere between $200-$300.
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Well it won't be until next week now. I switched out from these cheap electrical connectors for the auxiliaries to delphi weather pack connectors, they're just so much better. I guess, you get what you pay for. Seems I don't have an appropriate crimper for them. It's on the way, but I won't see it until next week.

I did settle on a $250 price point. That will get you the touchscreen in a case with the software installed, a hall effect sensor and load cell.

This will also be a great option for people who have old school manual dynos that want to introduce them to the 21st century.
 
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