Xander Posted June 8, 2005 Share Posted June 8, 2005 lately I have been working on building my own dynamometer. At first it will be a inertia type only (like a dynojet) But with provisions to expand to a brake type dyno. A friend of mine has a great metal work shop (think big/industrial). He made the roller. the outside diameter is 530 mm and about 25 mm thick. It is 2100 mm long. Te roller weighs about 825 kg and has a inerta of 46 Kg.m2. I still have to build the framework and get the rol balanced. For electronics I will be using this: http://www.sportdevices.com/dyno/sp1.htm I'll keep you guys informed. the tire is a 195/60-15 for comparison. Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted June 8, 2005 Share Posted June 8, 2005 You Guys Cease To Amaze Me!!! Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted June 8, 2005 Share Posted June 8, 2005 That's amazing! Good luck on your project, Mario Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted June 8, 2005 Share Posted June 8, 2005 Check the load rating of that pillow block bearing. Also, is the roller drilled through or is the shaft machined into the roller. I would use a larger through-shaft and bearing but I like overkill. Nice work. Does your buddy build ship engines or something? Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted June 8, 2005 Share Posted June 8, 2005 Awesome!! Quite a project, look forward to the end result. How portable will it be? What if you need to move it from your current shop to a new one? Rufus Quote Link to comment Share on other sites More sharing options...
olie05 Posted June 8, 2005 Share Posted June 8, 2005 That looks extremely portable to me compared with other roller dynamometers. That surface looks rather shiny, you probably should scuff it up abit or put some sort of traction aid on it so tires don't slip and give inaccurate readings. -Oliver Quote Link to comment Share on other sites More sharing options...
Xander Posted June 8, 2005 Author Share Posted June 8, 2005 cygnusx1: The pillow blocks are rated for 20 metric tons a piece and 3000 rpm. Which is more than enough for this project. The axle goes through the end plates and is welded from the other side ( the end plates are 61,5 mm thick). Also a radius is machined at the outside for added strenght. EvilRufusKay: How portable will it be? actualy I build it with portability in mind. I use a pallet jack which is rated for 1500kg. it is quite easy to move around. olie05: You are right about the surface. At my local poly service they sell a friction coating that is used for swimming pools. Very durable. I am going to paint it first with a 2 part epoxy primer. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted June 8, 2005 Share Posted June 8, 2005 all i can say is nice wheel and yes our buddy does built shipyard parts, among various other heavy industrial parts, this rol is allmost considerd small to their standards this is one of their machines that last one is where that roll was made on aswel Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted June 9, 2005 Share Posted June 9, 2005 after you finish this i want to know how much horse power a single man running on the roller has....? hehe also why not a Gtech instead of a gigantic dyno? is it more precise? i also assume you want rwhp not real hp (after aerodrag) Quote Link to comment Share on other sites More sharing options...
frank280zx Posted June 9, 2005 Share Posted June 9, 2005 well rwhp is real HP what you got on the crank doesnt really matter.. compare it to money in the bank if you will.... if you are washaed ashore on an island with just some cash... you might be a millionaire back home, but what is teh use when you cant spend it ? the running man is actually a good idea haha and yes this is more precise...besides it looks cool Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted June 9, 2005 Share Posted June 9, 2005 Hey group: This is really cool!! I have kicked the idea around for years to try to build my own dyno and was excited when I saw the subject to this thread. Unfortunately, it seems a little beyond the average do it yourselfer's capabilities. Years ago, when I was roadracing motorcycles, I worked for a machine shop specializing in working on racing motorcycles, it was small. We did some work for some guys racing go karts with Briggs and Stratton (S?) engines. We began to do development work and rigged up a crude dyno. It was a power steering pump off a car bolted to a fixture that allowed us to attach the briggs motor to the drive pulley. We had a reservoir of hydraulic fluid hook to the lines. On the outlet from the pump we had a pressure gauge. We could run the motor at a steady speed while making changes and if the pressure went up on the gauge, we knew we were making more power. I know it, like I said, it was crude. But it worked!! There was no easy way to calabrate it to give HP numbers, but as a tuning tool it was effective. In fact, the motors we were working on began to be more competitive and others from the same league began to show up at the shop asking about getting some work done. Unfortunately, as we learned to build and tune these lawnmower engines to ever higher degrees of tune, the short comings of our little dyno began to appear. We began to blow hoses under higher pressure and the fluid began to get very HOT!!!! We replaced hoses with stronger ones and even considered rigging a cooling radiator for the fluid. We were pushing the limits of the pump and considered a bigger hydro pump. In the end the shop moved onto other projects and the idea was dropped. But I never stopped considering assembling something similiar for my bike engines. I've even considered using an electric generator instead of the hydraulic pump and feeding the power back into the grid! Just some crazy ideas. Momentum dynos that test rear wheel HP are great, and my hat's off to you for building this baby, but a engine dyno that the engine can run at a steady RPM while changes are made is the only way to make many incremental changes and see the results immediatly. Yes, it's harder to pull the engine and mount it to the dyno. sorry for the long post Quote Link to comment Share on other sites More sharing options...
Xander Posted June 9, 2005 Author Share Posted June 9, 2005 hi mom, The only thing that I can't make myself is the roller. oh and balancing that monster. the rest is just plain old welding, sawing and grinding. after that there is painting and electronics. nothing special. I will be using a 27 tooth sprocket as a pulse generator. I heared that a dynojet measures rpm with just one pulse per rev. So in theory this thing wil be 27 times more accurate. Here is a picture shamelessly ripped from a other dynamometer site. Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted June 10, 2005 Share Posted June 10, 2005 Couple of questions if I may... As a momentum dyno, is there a limit to the amount of time you can run? Does the momentum of the roller come into effect at some point? If RPM's are calculated via the sproket how is torque derived? Will there be a brake incorporated into the system to achive torque values? Quote Link to comment Share on other sites More sharing options...
frank280zx Posted June 10, 2005 Share Posted June 10, 2005 by messuring the speed of teh roller comming up to speed ( time it takes to spoll 800 kg of roll) Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted June 10, 2005 Share Posted June 10, 2005 by messuring the speed of teh roller comming up to speed ( time it takes to spoll 800 kg of roll) cool thanks! Quote Link to comment Share on other sites More sharing options...
Xander Posted June 11, 2005 Author Share Posted June 11, 2005 A small update: I made a testrun with my daily driver. As I was slowly raising the speed I noticed that at 60 mph the whole thing started to move slightly. So for now I must limit the top speed to 60mph until I have the drum balanced. All in all I am pretty happy with the stability of the system. I actually made a test run with my roaddyno hooked up. This gave me a pretty good graph but the peak numbers are way off. Next step is some more welding and painting and finding a place to balance it. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted June 15, 2005 Share Posted June 15, 2005 A small update: I made a testrun with my daily driver. As I was slowly raising the speed I noticed that at 60 mph the whole thing started to move slightly. So for now I must limit the top speed to 60mph until I have the drum balanced. All in all I am pretty happy with the stability of the system. I actually made a test run with my roaddyno hooked up. This gave me a pretty good graph but the peak numbers are way off. Next step is some more welding and painting and finding a place to balance it. This is a really cool project. Something way beyond what most guys could do. I've got one question though. Who's in the car driving it during the picture? Doesn't look to me like anyone is. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted June 15, 2005 Share Posted June 15, 2005 what car ??? lol you mean that go mobil ? but yeah xander good Q... I guess xanders got lucky on this project if we would not have had a machine shop buddy this project would be much harder to realize Quote Link to comment Share on other sites More sharing options...
Xander Posted June 15, 2005 Author Share Posted June 15, 2005 cody, No one is in the car in that picture. The wheels are only turning at something like 5 mph. It was idling in 1nd gear. It is not that light in my workshop so my camera is a bit slow. hence the wheel blur. Quote Link to comment Share on other sites More sharing options...
tyson Posted June 18, 2005 Share Posted June 18, 2005 Nederlands is de domste taal van hen iedereen Quote Link to comment Share on other sites More sharing options...
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