# Dyno's and power supplies



## Hornet (Dec 1, 2005)

Been playing with dyno's a lot lately,

If any of you guys are looking at building yourself a roller dyno,or a slave motor dyno,you'll want to probably put more power to it then you think it needs.

I had one 19.5 volt 3.42 brick powering both Solo's and Boosted's dyno's,figuring it should be enough,got my eye's opened up.

Using just an old poly car with a 35 Spinner in it,the car would draw 3.15 amps when i pinned the throttle opn Solo's dyno.
Got me thinking that was mighty close to the bricks rated output,and i wondered if i was short changing the car on power.
So i piggybacked another 19.5 volt 3.42 amp brick onto it,and low and behold the same car now pulls 4.35 amps,and definitely spins up faster.
So if you're looking at building yourself a dyno,it's worthwhile looking into the amp draws the cars you'll be testing on it draw,and power the dyno accordingly:thumbsup:
I'm in the process of looking for a couple more laptop bricks to add to both dyno's
Rick


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## slotking (May 27, 2008)

yes I saw that as well.
but I think at that amp, there is a heavy draw somewhere

my 6mag unlimited cars were under 1amp at full speed

HOPRA setup poly mod at a 10amp min per lane and neo cars have to use battery power.

I have just never had a car over 1amp at speed


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## Hornet (Dec 1, 2005)

I can get most of the higher end style cars to draw a steady 3 amps or more on my old slave dyno,and the really radical stuff will hold 5 amps.
With the slave dyno,i can put a pretty good sized load on the cars.
My figuring on the dual slave versions,is if my output slave motor is putting out a 7 volt reading,i should be getting a comparable output from the loadable slave,and when i throw the load motor into full short mode,it should be putting a comparable 6 or 7 volts load back into the system.

On the roller dyno's,there's a lot of inert mass to get moving with the roller and disc,and it takes a pile of amps to get things rolling.
My biggest problem with both roller dyno's is tire spin that turns into wheel hop with the fast cars,but we're working on that:thumbsup:


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## slotking (May 27, 2008)

that's why I like the VRP dyno, the roller is pretty true, you can set an inline on and walk away.

Ie.. I use it to find wheel hop.


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## Boosted-Z71 (Nov 26, 2007)

In Rollers, true and balanced are a big difference, I have a pretty hot modified (Thanks Rick) to test with, and after balancing it has no shake at all. And the plus is you get plenty of helpfull data. Its very easy to see brush spring tension fall off, com bounce, or even heat build up. Another plus is you can save a file with a graph, with all the data, rpm - roller, wheel & motor, torque, power, speed, as well as amp draw, and slave motor output & test voltage. So its a really easy way to keep an eye on the performance of a car. 

Boosted


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## Hornet (Dec 1, 2005)

Hey i owe you more then just a car,lol

I know balancing Kens dyno has made a world of differance,it spins up 10 times better now.

And the upgrades you've come up with for your dyno are the ticket:thumbsup:

Mike just to let you know Lyle has a VRP,:wave:
He's had it for quite awhile:thumbsup:
It's good too,but these are better,they just have some teething pains,but they're getting sorted out:thumbsup:


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