# Home built dyno



## Hornet (Dec 1, 2005)

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## Boosted-Z71 (Nov 26, 2007)

Yes, I saw one like that on E-bay & then took his idea & went my own direction, I added a dedicated power source 22 volt Aurora transformer, and hand controller, I can do warm-ups on here as well, a car cooling fan, (the bigger slots by the guide pin slot allow airflow through the car) the push connections in the front for a VOM meter, & I also added the port on the left to read the rpm of the rollers with a laser tach. I also modified the original sensor wheel to increase the sensitivity of the read out of KMH of the digital output, as the scale read by this dyno was originally made for larger RC cars & many times a small increase in your HO car output would be too small to show a 1 KMH increase, so I have it where I can read 1/4 of KMH, which relates to 4 KMH on the digital read out. I can easily switch the output scale reading to match the car type, 1-1, 2-1, 3-1 or 4-1. Big difference in wheel speed between a T-jet & an inline. 

Anyway this is my homemade dyno, I can read about anything, RPM, Wheel Speed, Voltage, amp draw, plus the car warm up feature . 

Boosted


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## Hornet (Dec 1, 2005)

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## Boosted-Z71 (Nov 26, 2007)

Thanks, I did think about an article or even building some for sale on E-bay etc, but like everyone else I spend time doing other things, Family, School, work etc. Also I would have to get someone to take the pictures, that is one thing I have No talent at. 

Boosted


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## slotking (May 27, 2008)

good job

looks like the base is from the other dyno for the bigger cars??
rick post is another guy who wrote an article on converting the big car dyno over to ho.

the only issue I saw with that 1 was it had no load on it.


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## Boosted-Z71 (Nov 26, 2007)

The base is a Tamiya 4wd speed checker, Your right, it does not have an applied load originally, other than the friction of the roller axles & a gear driven setup (not much), but that was an easy fix, what I did was to add a wheel / tire to the side of one of the rollers to add a bit of friction with an adjustable screw. I did some calculations on what additional weight a t-jet & inline car would pull decently & compared amp draw doing the sled pull test & and then adjusted the dyno accordingly to the known amp draw for a couple cars (Kinda best average) and I left it at that, I am sure there is a better way to determine & gauge how much resistance force you should have on the rollers, and of course the car overcomes the force as the force applied does not increase as the run progresses such as a real hydraulic dyno would. I took a look at the VRP unit & would like to see one of those up close, looks like a good unit. You have to be careful on a loaded dyno, cars build armature heat quick, hence the fan install to help a bit.

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## slotking (May 27, 2008)

> I did some calculations


That alone leaves me out of the conversation!
heck what is a calculation:freak:


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## Hornet (Dec 1, 2005)

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## Boosted-Z71 (Nov 26, 2007)

Slotking that is funny, I did not say Scientific Calculations, you know more just like Jethro "cyphering", Ha Ha.

I wanted to try a slave motor, but room is getting to be scarce around the rollers, I may crack it back open here sometime just for another look see. If so I will snap some pics for you guys

As time permits I will try to start working on a write up on this.

Boosted


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## Ogre (Jan 31, 2007)

One more.

http://sites.google.com/site/speedinchowto/home/ho-dynometer


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## slotking (May 27, 2008)

thats closer to the 1 I was trying to make:wave:
but I was using a single project box and digital volt meter for more accurate readings.

Then with the small and easy to vrp dyno, it was like why bother! 
and it small to carry in my slot case.

I even stopped using my 1960's 1/32nd scale dyno!
maybe i should sell it! LOL


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## Hornet (Dec 1, 2005)

edit.


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## Joe65SkylarkGS (Feb 15, 2010)

I have the VRP.

Niced unit. :hat:


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## slotking (May 27, 2008)

I am kind of an idiot so the vrp really helps because it does not matter what side is pos or neg!:freak::wave:

LOL


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