Homemade 700hp inertia dyno idea, not solid steel but sand filled rollers

admin

This is just something I came up with, $500 per dyno tuning kind of get's expensive so I'm thinking of idea's of making my own dyno, the rollers are the most expensive part in my opinion.From my calculations I need 4 2500lb rollers for a 700 hp dyno, I kept thinking where the heck will I get a 36" round stock steel 36" long, not cheap so I thought of an idea to use thick walled tubing filled with 150 per cubic foot fine grain dry sand like your old style weight lifting weights.  Which puts me at about 20 cubic feet or 3000 lbs.Weld the caps with solid 3" axles and have it balanced, record the inertia, max rpm for setup is 1800rpm at 120mph.  Heck I could probably do it in two rollers. Tell me I'm crazy?Last edited by kazx9r; 05-08-2012 at 09:46 PM.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Having serviced a dynojet for a few years.. I think it would be doable.. iirc it was a 248c with 2 48" rollers. They sit on large pillow block bearings, an electrically controlled pneumatic valve for the braking (that needed constant adjustment) and an rpm sensor Sent from my Galaxy Nexus using Tapatalk 2Miller: 200dx, Bobcat 225, Passport, Powermax 45, Milwaukee: Dry Saw, MagDrill, grinders
Reply:You gonna have a lot more than 500 in building your own legitimate dyno setup with all the diagnostic tuning software your going to be in it a lot more. There is a reason they charge so much for dyno pulls that's because not only is the equipment expensive but so is the software and the knowledge of how to properly tune a vehicle by the numbers it puts down. I don't know where your taking your ride to but I get 3 pulls on the dyno for $80.1973 Lincoln SA 200, Already replaced shunt coils, Idle board (SOLD)1984 Miller Dialarc 250HF, Miller water cooler, 250 AMP water cooled torch, you know the worx.
Reply:I hear ya, the dyno software isn't the issue, tuning I got covered with my own software after paying for tuning that one time but its $80-100 for 3 pulls here as well,  ...my wife will never let me drive the car on the road, plus trailer it add's up, like I said its just a crazy idea.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Why have a car you can't drive? Lol just busting your chops a bit.1973 Lincoln SA 200, Already replaced shunt coils, Idle board (SOLD)1984 Miller Dialarc 250HF, Miller water cooler, 250 AMP water cooled torch, you know the worx.
Reply:lol are you wanting to make a dyno so your wife will let you "drive" your car? Welding/Fab Pics: www.UtahWeld.com
Reply:Originally Posted by Tuscany I don't know where your taking your ride to but I get 3 pulls on the dyno for $80.
Reply:I always read and heard you want the drums to weigh as much as the car itself. The local dyno has 2000# drums which is perfect for my crx.
Reply:I saw that, Scandinavian rednecks, just great....anyway, I can't drive it so I guess a dyno would atleast give me some fun, its probably safer for everyone, big power on the road is just too tempting.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:The sand may shift under the heavy acceleration 700HP would cause.  Why not fill it with concrete?  Weld on a few short pieces of angle iron on the inside before pouring.  That should keep it well bonded to the pipe.  I wouldn't worry about rebar.  It's all contained inside the pipe.  It doesn't really matter if it cracks.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by AndyAThe sand may shift under the heavy acceleration 700HP would cause.  Why not fill it with concrete?  Weld on a few short pieces of angle iron on the inside before pouring.  That should keep it well bonded to the pipe.  I wouldn't worry about rebar.  It's all contained inside the pipe.  It doesn't really matter if it cracks.
Reply:How many times do you have to have your car dyno tuned? Learn to tune yourself it's not hard.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:I can rewrite the code if I wanted to, did you read my above post, I paid that years ago and after that I said, never again, bought my own software, I use binary editor like most Ford guys do but its kind of hard to tune when I can only drive the car at the track or on the dyno.I think a drive on roller dyno will eat up too much space, I think a hub dyno is safer, more compact, easier to move, don't need a big trailer with you, don't have to worry about wheel diameters and slippage, although, harder to mount, the coupler would have to be something special like a rubber or something like urethane and syncronizing the rollers is gonna be difficult since with an LSD I'm betting is rarely a 50/50 power distribution, problem with both roll on and hub style dyno's.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:It would be a lot easier to build a MUD dyno.  In the early 90's I worked at a fabrication shop that was next door to a seriously redneck auto repair place.  One day we heard a lot of racket from behind their shop and had to see what they were doing.  They had a car chained to a tree behind the shop.  Water hose turned on the ground at the back tires.  One guy sitting in the car running the throttle, another guy under the hood adjusting the timing for best power.  At that point I officially coined the term MUD DYNO.  Cheap, and simple!  They did it with other cars as well...I was thinking a little higher tech than concrete.  Mix the sand with some sort of resin - epoxy, etc before pouring it in.  Should be a more consistent mixture when done.
Reply:Originally Posted by TubularFabIt would be a lot easier to build a MUD dyno.  In the early 90's I worked at a fabrication shop that was next door to a seriously redneck auto repair place.  One day we heard a lot of racket from behind their shop and had to see what they were doing.  They had a car chained to a tree behind the shop.  Water hose turned on the ground at the back tires.  One guy sitting in the car running the throttle, another guy under the hood adjusting the timing for best power.  At that point I officially coined the term MUD DYNO.  Cheap, and simple!  They did it with other cars as well...I was thinking a little higher tech than concrete.  Mix the sand with some sort of resin - epoxy, etc before pouring it in.  Should be a more consistent mixture when done.
Reply:I'd be afraid of the sand wearing away the inside of the steel spinning around at rpm like that. I like the idea of filling with concrete, then you can drill out where necessary to balance it properly too. If anything, water is 8lbs/gallon.....you could simply fill to the volume necessary then drain when not needed? Just brainstorming.Hobart EZ-Tig newbie.
Reply:Any chance you have a construction equipment wrecking yard or serious scrapyard where you could repurpose existing rollers from something else, say an asphalt roller?You might even be able to buy one, skin out the parts, then scrap the rest.
Reply:Originally Posted by chimmikeI'd be afraid of the sand wearing away the inside of the steel spinning around at rpm like that.I like the idea of filling with concrete, then you can drill out where necessary to balance it properly too. If anything, water is 8lbs/gallon.....you could simply fill to the volume necessary then drain when not needed? Just brainstorming. .
Reply:Actually, the media cannot be left spinning around freely - that's the problem with just packing sand in there.  For the inertia concept to work it has to all move as one.Years ago I worked at a company called Tug that built baggage tractors and conveyors for airports.  I always meant to grab a couple of the conveyro rollers - they were about 12" diameter and had a knurled surface.  Of course I was thinking about using them to drive a water brake rather than use inertia...
Reply:Good point, the epoxy with silica sand might be doableOn a side note, the Dynojet one is 24" with 6.75ft roller which is the exact volume I came up with....but its a 2000hp dyno.  Wonder if they can give me the roller weight.Last edited by kazx9r; 05-09-2012 at 04:44 PM.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Got these guys to reply back, saying http://performancetrends.com/"I figured for 700 ft lbs finishing the run at 130 MPH (1820 RPM)24" OD x 96" long (or 2 x 48" long) with 19" ID (2.5" wall)Accel would be over in 5 seconds, which is what we like to see minimum for good accuracy."So I'm assuming its a hollow roller which is about 6134 lb's, that sounds about right.My questionSecondly, about the software, how can two drums be calibrated if lets say a car has an open differential only one will drive the roller or an LSD where both will drive but its usually, I'm assuming, a 50/50 distribution, how do I account for synchronization?AnswerBad assumption.  Tie the 2 rollers together with common shaft.I don't see how this is possible for a hub style dyno?Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Originally Posted by kazx9r. . .I think a drive on roller dyno will eat up too much space, I think a hub dyno is safer, more compact, easier to move, don't need a big trailer with you, don't have to worry about wheel diameters and slippage. . .
Reply:Dynojet got back to me, they said the 224x system weighs 4500 lb's I must be overestimating the roller weight.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:After doing some more research it seems 2 x the gross vehicle weight is a common value for roller weight, so I was over estimating.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Looks like the hub style is out, it must share a common axle, so its a single 24" roller or 4x18", I may get away from the sand mix, the steel is not as crazy as I thought, quote I got was $3500 for 4x4ft 18" rollers with 2.5" wall, I'm shooting for $1500.Reason four 4ft is better, I can do it only most lathe's and mill's. From experience, I needed a chunk of aluminum 12 x 18 x 12" started the quote at $3000 and got it down to $755, took some digging though.CORRECTION its $3500 a piece, got another quote for $1800 a piece, need to go import on this.Last edited by kazx9r; 05-10-2012 at 03:40 PM.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3Originally Posted by kazx9rThis was my initial idea and still open to it but I was worried about the porosity and consistency of the concrete and it might break inside, cracking the entire tube, so what's the angle iron for?
Reply:Originally Posted by AndyAThe angle iron is to make sure the concrete slug is firmly attached to the pipe.  If it's smooth wall pipe there's a chance the concrete slug could break free and slip.
Reply:I have a homemade inertia dynoAn old page is at http://homepages.ihug.co.nz/~gmerryweather/. I can't update it as I am no longer at that ISP, and haven't foudn another web page provider yet.It hasn't been used for quite a while as I stopped racing, bought a house, had kids and ran out of money...Mine uses the Performace Trends package. It works, is supported and a plug and paly option.Pay the extra and get the pro (or next up from cheapest) package with the pro software, with the spark plug pickup etc.Another option is Sport Devices in Europe. There are spreadsheets to let you calculate the inertia - I think there is one on the sport devces page. also one here http://dtec.net.au/Tech%20Articles.htm geoff
Reply:how about you disconnect your driveshaft and drop in a differnt one attached to a surplus water brake dyno.  or an electromagnetic driveline retarder for trucks.or an instrumented driveshaft and run down the track.just a thought.
Reply:Originally Posted by GeoffmI have a homemade inertia dynoAn old page is at http://homepages.ihug.co.nz/~gmerryweather/. I can't update it as I am no longer at that ISP, and haven't foudn another web page provider yet.It hasn't been used for quite a while as I stopped racing, bought a house, had kids and ran out of money...Mine uses the Performace Trends package. It works, is supported and a plug and paly option.Pay the extra and get the pro (or next up from cheapest) package with the pro software, with the spark plug pickup etc.Another option is Sport Devices in Europe. There are spreadsheets to let you calculate the inertia - I think there is one on the sport devces page. also one here http://dtec.net.au/Tech%20Articles.htm geoff
Reply:Originally Posted by dsergisonhow about you disconnect your driveshaft and drop in a differnt one attached to a surplus water brake dyno.  or an electromagnetic driveline retarder for trucks.or an instrumented driveshaft and run down the track.just a thought.
Reply:Will get back to you all.Last edited by kazx9r; 05-11-2012 at 03:06 PM.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Hey getting back to the inertia type, instead of putting the car on heavy rollers, how about a roller reduction system link with a big chain, this would greatly reduce the speed of the heavy roller.So says my max rpm at the hub is 2000rpm max with a 4.5" hub and then using a 36" 2000 lb drum linked with a chain, giving me a reduction of 8:1, so giving me a drum speed of 250lb, this eliminated a few issues.Obviously the heavy roller will sit in front of the car or rear if its RWD, linked with chains to BOTH wheel hubs, basically putting a car in high gear.  But how to calculate the weight and size of the heavy roller to simulate the weight of the car.You all see what I'm getting at?Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3
Reply:Over the last few days,  I've been using surplus brain capacity  to mentally build a poor-boy  dyno. IMHO the only practical way to build a budget dyno will be by reutilizing something that's  already half built. Some of the numbers quoted earlier would  take the heart right out of the project.One passing thought was similar to your chain idea, but I thought about using wide flat drive belts over the test car's tires, to drive the jackshaft or roll.Another thought I had was utilizing a cushion-tire forklift truck's axle as the rolls. The differential could be removed and the axle shafts connected together to lock the separate "rolls" together as one. Utilizing the forklift axle would  basically create an instant matched pair of very heavy duty "trued" rolls, complete with rubber tread and precision bearings, all conveniently mounted to a heavy housing. Myself, I believe I'd lean towards hydraulic loading rather than inertia.Or mechanical... grind grain with it. Good LuckLast edited by denrep; 05-11-2012 at 11:37 PM.
Reply:Try this one:http://www.aemelectronics.com/ Attached Images
Reply:Originally Posted by a1998z3Try this one:http://www.aemelectronics.com/
Reply:Man that's cheap.  Last time I bought a rotating torque meter was for a 25 horsepower electric motor and the cost was close to $10,000 through S. Himmmelstein Company.Last edited by 76GMC1500; 05-12-2012 at 06:10 PM.
Reply:Loos like a good idea to me and the software is free.....good luck.
Reply:Originally Posted by kazx9rNice, wonder if it can be used without driving the car.
Reply:You could simply apply a strain gauge to your drive shaft.  You simply need to apply some known torques to it to generate a calibration curve.  You know, once you figure out wireless excitation.http://www.omega.com/ppt/pptsc.asp?r...ELEMENT60&Nav=
Reply:Originally Posted by 76GMC1500You could simply apply a strain gauge to your drive shaft.  You simply need to apply some known torques to it to generate a calibration curve.  You know, once you figure out wireless excitation.http://www.omega.com/ppt/pptsc.asp?r...ELEMENT60&Nav=
Reply:I think for the money your thinking about spending on building your own dyno you should just take it to a shop with one and have it tuned.1973 Lincoln SA 200, Already replaced shunt coils, Idle board (SOLD)1984 Miller Dialarc 250HF, Miller water cooler, 250 AMP water cooled torch, you know the worx.
Reply:Originally Posted by TuscanyI think for the money your thinking about spending on building your own dyno you should just take it to a shop with one and have it tuned.
Reply:Maybe this will be easier, I found these guys as well, price says $1600 but that was 2011 for the RB010, http://rebang.en.alibaba.com/http://rebang.en.alibaba.com/product...amometers.htmlbut it needs to be sized correctly.Singe Family House w/ 2 car garage-9" x 40" 1.5hp Vertical Mill, 2500lb-20"  Monarch Lathe -Lincoln IdealArc  TIG 250 -Lincoln MIG Pak 10, oxy-act setup-10" Mitre, Dewalt DW888, 200rpm drill press, 80g air compProject: Ford w/ Whipple 2.3