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Homebuilt Dynamometer?

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Old 02-04-2010, 02:28 PM
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Default Homebuilt Dynamometer?

Hi!
Well you probably hoped to see a homebuilt dynamometer? I have to dissapoint you. not anymore! look at page 2

We`ve built a few cars this winter (track/fun) and have to get them tuned. Since we always do everything our self we are offcourse looking into making a dynamometer. Actually we dont need to measure HP. We only want to be able to tune without doing it on the road since these cars arent very popular.

First of all, if anyone ever has come up with a stupid ide of how you could build a "cheap" and functional dynamometer/dynaoack/etc i want to know!

We`ve been looking at:
1. Pumps. Using pumps to pump oil/water. Pumps are used in comercial dynapacks etc but often expensive. We have pumps for pumping cow **** out of the barn but they arent big enaugh?...
2. Big steel drum with some kind of brakes. This way we can do drags and then brake the steel drum down to low speed.
3. This is REALLY stupid. Strapping the cars down to the rear wheels on an old truck. Using brakes, engine, driveline as something to hold the torque. We have no ide what resistance it is in a truck. Probably not enaugh?

I feel i lack some of the physics when trying to calculate what i need. If someone got input iwould be happy to know!!
If you think its stupid dont use energy telling me.. I KNOW!!!
On the other hand.. I hope moste ppl just think its fun..

Last edited by RexDiablo; 02-14-2010 at 03:34 PM.
Old 02-04-2010, 02:36 PM
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buddy of mine has a PC120 excavator and his dad drove semi trucks, they dug a trench and installed a semi rear end in the ground and hooked the brakes up somehow and could tune their 1000 hp mustang good enough to run 8s... impressive.
Old 02-04-2010, 03:07 PM
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COOL! Thats the cheapest solution and probalby alot of fun!
Old 02-04-2010, 03:10 PM
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minus the cost of the PC120... lol
Old 02-04-2010, 03:28 PM
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Wè got a excavator! Not sure how big.. I think i misunderstood though! What did he need the excavator for? =P

EDIT: HAHA.. okey, i understand .. for the hole ^^
Old 02-04-2010, 04:30 PM
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haha i was gonna say how the **** you gonna dig a hole without one!
Old 02-04-2010, 07:32 PM
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actually the semi truck rear axle seems like a pretty good idea if you just need some way to drive/tune the car while being stationary. Plus they have air brakes so you could just use compressed air to operate the brakes. Strong enough to hold any weight or punishment you can throw at it. All while being cheap and able to get parts easily. And the brakes are huge and can withstand lots of heat if you want to "load" the dyno during tuning sessions. I like it!
Old 02-05-2010, 02:36 AM
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Im gonna digg the truck out of the snow this weekend and see if its usable!! I think it is. Maybe having made some water cooling system on the brakes will help them last longer!
Old 02-05-2010, 08:51 AM
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i got an ol rockwell rearend out of a ltl 9000 ford if your in wisconsin
Old 02-06-2010, 08:50 PM
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Here you go
http://gallery.floridasupras.com/alb...l_MVC-035S.JPG
http://gallery.floridasupras.com/alb...l_MVC-034S.JPG
http://gallery.floridasupras.com/alb...l_MVC-039S.JPG
Old 02-06-2010, 09:28 PM
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i dont think tires on tires would be as accurate
Old 02-07-2010, 09:16 AM
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Originally Posted by smok'nZ
i dont think tires on tires would be as accurate
as accurate as what? Nothing is being measured.
Old 02-07-2010, 10:05 AM
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3rd gen with a trailer home in the background. Who would have thought this thread would bring one of those pics out?

Last edited by 01ssreda4; 02-07-2010 at 10:36 AM.
Old 02-07-2010, 10:25 AM
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hahahah ^^ thats great
Old 02-07-2010, 01:23 PM
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Thats EXACTLY what i had in mind!
Got some more specs on sizing of the trailer rear and how well it worked? For how long can you brake the car?
Old 02-07-2010, 01:56 PM
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None of that seems like a good idea. Wow.
Old 02-07-2010, 02:53 PM
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what i would do is use the pumps. mount them to the wheels and complete the system by just putting the lines in a circle. you will be able to adjust load via valves and it would be extremly easy to get comparative results for hp if you ever wanted to. for similar setting in the pump system just mount a pressure transducer somewhere in the line and log it via a data acquisition software such as labview. you wont get hp numbers but for 2 different maps you will know which one is best.
Old 02-07-2010, 02:58 PM
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Pumps are usually very expensive..? if the engine produces 400KW i need something to waste that energy with!
Old 02-08-2010, 02:21 AM
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I was just thinking about this over the weekend. A home built "dyno" that doesn't actually measure HP, but just something you could load the car with so you can do tuning/data logging without having to go tear it up on the street and deal with police. I'm not sure that a pit with a axle/tires is the best idea though... A local guy that runs a small 4-wheeler/bike shop built one.. I'll have to stop by again and ask him some questions about it.

And LOL @ the 3rd gen/trailer house.
Old 02-08-2010, 03:06 AM
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Originally Posted by LilJayV10
None of that seems like a good idea. Wow.
Yeah, I laughed pretty hard at seeing that.


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