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i remember years ago, readding a rcca car article and someone made or sold or had a dyno, that would measure "rear wheel power" off a car. it basically hooked up the same way a regular car does, onto 2 metal cylinders and the power was measured at the rear wheels. i remember the car having special wheels in the rear to test the power, but it was a very cool thing..

has anybody ever seen one, heard of one or otherwise used one.. i would be interested in something like this.. i have motor dynos, and found them ok.. but i would like to see with the gearing hooked up, how much power is being used/lost

The wheel and the lack of traction was the first thing that popped into my mind. I guess you could try to do it with non spiked tires, but the key would be taking as much friction out of the rolling cylinders as you possibility could. I guess you could go with a direct belt or geared system if you were innovative enough and had the math skills. Anything is possible.

Personally, I don't recall seeing anything in the magazines, so I can't help there.

yea i remember them using a special tire (large hard rubber) to test, but it was the same rim, i think they did it on a lunchbox and a onroad car, just to show what it was capable of. im sure it wasnt terribly accurate and thats why we dont see em really.. but thought it was a cool thing

It does sound like a cool idea, I would like to see the article myself.

if i had to guess, i would say its a 87-88 issue, probably leaning toward 88 though.. article was on on road racing i think, i really forget.

what i remember was the rolling tubes where lightweight plastic with a metal bar and spacer at the end of tubes, and i think it had a magnet at the end and a sensor that calculated the rotation. i dont remember it being terribly complex, meaning it didnt read throttle curves or anything like that, rather just top end rpm speed, kinda cool

Hey Mike, I think I saw it too, so I don't think you are dreaming, at least no more than normal.

Of course the traction is an issue, just like full scale. So you just tie the car down tighter than just gravity I guess, as long as you don't bind anything up. Probably with special hard tires as mentioned. The roller material/coating selection could help.

Not terribly complex to build, except for generating the back torque in the dyno and generating accurate readings. Probably generate torque with a variable load on a slave motor? Would take some $$ for a good load cell and readout device, or possibly a homemade strain gage/bridge set up (calibrated) to get accurate readings. Or adapt a traditional motor dyno perhaps? Certainly need a speed reading or it's essentially useless.

This is kind of down my alley, one of my day job thingies is a significant test lab. If I only had more time and money......course if that was true, I probably would be playing less with TOY cars..... On the other hand, at least this way I'm still alive!

parms/pse made one strictly for pan cars called the THOR chassis dyno. they were made in 20 amp and 30 amp models and had a pan car axle/tire jig out the back the the test car sat on. i haven't seen one in years sometimes there is one on ebay evry now and then.

that was it i believe!

I actually used a chassis dyno at the Encino Thunderdrome race (many years ago) when I ran pan cars. It would use the battery in your car, jump it directly to the motor and give you the top end/efficiency you could attain.

Still didnt help me that day....LOL, I finished in the lower 20's overall.

It was a really neat set up though.

I just found one of the PSE ones at a hobby shop! So what are these things worth? This one is used, no box, no instructions. I asked the guy what he wanted for it and he said $100. He didn't even know what it was so maybe he would go lower. I know its been sitting there for ever. I'm not really interested in it but if one of you wants me to pick it up I will and ship it out to you? Let me know

i would like to hear more on this also
1 more oldie to bring back into the light
marty