ESE's works engine tuner

[Ocean1]

Unless it's a truck balancer I think it would be to heavy and it's probably to long anyway, you'd also have to make some kind of adapter to be able to bolt it up

You could do a static balance easily enough if you had a couple of v blocks and bearings to suit or even with it in the frame

Knife-edges would be the traditional way, and yeah you can get it good, but only in a single plane. Wouldn't actually cost that much to get Howitts in Naenae to do it.

[wobbly]

This is what is on my engine dyno.

http://www.sportdevices.com/dyno/sp1.htm

I have used this setup for over 12 years, with a couple of upgrades by selling the complete dyno ,and rebuilding better - as I am doing right now.
A great system, and the software can be downloaded and used at any time.
Using 152 teeth input on the starter wheel, it can resolve 1/10 Hp changes in a KT100 with amazing repeatability, as long as you use an egt, head and case temp setup to replicate
engine heat load on every test.

Frits is right ( as usuall ) about the acceleration dyno being the most useful.
I set up the engine gear ratio to test, so it accelerates as it would as close to track conditions as possible.

But an eddy current can be set up to work exactly like an inertia, simply by using the constant load mode.
Then the absorber applies the same load to the engine all the time, just like a steel wheel or roller.
Advantage is that on say a Dynojet you can easily dial up the load needed in % terms, to get the acceleration rate you want.
We use that facility with a twist - program it to increase the load with roller speed.
Thus when doing an all gear run, the load increases just like the wind drag with increasing speed - so the acceleration rate decreases.
Perfectly mimicking the track conditions.
Means you can dial in the ignition and fuelling at very high acceleration rates in the lower gears, then do the same at slower rates in 5th/6th.

[bucketracer]

Keeping up the corner speed.

[richban]

Keeping up the corner speed.

Gay...........

[Ocean1]

Thus when doing an all gear run, the load increases just like the wind drag with increasing speed - so the acceleration rate decreases.
Perfectly mimicking the track conditions.

I've heard of older dynos that use a monty great fan as the load, for similar reasons.

Think the rate of change would be too high to simulate drag in race conditions. You could, however add a smaller fan, driven off an existing roller to get pretty close, and throttle the fan intake to fine-tune it.

Is there a market for these things, guys? Or are they worth just whatever spare time you have to make one?

[Sketchy_Racer]

I've heard of older dynos that use a monty great fan as the load, for similar reasons.

Think the rate of change would be too high to simulate drag in race conditions. You could, however add a smaller fan, driven off an existing roller to get pretty close, and throttle the fan intake to fine-tune it.

Is there a market for these things, guys? Or are they worth just whatever spare time you have to make one?

Yeah there is a market, but there is a reason a commercially available dyno is upwards of 10-15k. To build one "properly" would be a great cost, where ours are made of scrap metal and although be useful wont be as versatile as a professional unit. I would imagine that if we put our DIY units up for sale we may get a couple of thousand for it, but it is only worth what someone is prepared to pay for it.

I am looking into building a trailer to house mine, but that may be a while away I have run out of room!

[Yow Ling]

Is there a market for these things, guys? Or are they worth just whatever spare time you have to make one?

There is a desire to own one, but usually as far as it goes. You can buy a FXR for the price of making one, and most bucketracers are a little more cost conscious than your average 600 or 1000cc racer. Sketchys one looks great because it looks like it can be stored under a bed or in a wardrobe.

Maybe having a dyno is like roasting your own coffee beans, can be done but there is a bit of dicking around involved, you have to be keen

[jasonu]

Totally Gay...........

Fixed it for ya

[dmcca]

It's the other way around. High-inertia rollers do not mask anything. Controlled brakes of any type do, especially the 'advanced' variety with step test facilities...

Frits is right ( as usuall ) about the acceleration dyno being the most useful.
I set up the engine gear ratio to test, so it accelerates as it would as close to track conditions as possible.

But an eddy current can be set up to work exactly like an inertia, simply by using the constant load mode.
Then the absorber applies the same load to the engine all the time, just like a steel wheel or roller.
Advantage is that on say a Dynojet you can easily dial up the load needed in % terms, to get the acceleration rate you want.
We use that facility with a twist - program it to increase the load with roller speed.
Thus when doing an all gear run, the load increases just like the wind drag with increasing speed - so the acceleration rate decreases.
Perfectly mimicking the track conditions.
Means you can dial in the ignition and fuelling at very high acceleration rates in the lower gears, then do the same at slower rates in 5th/6th.

Thanks Frits and Wobbly, very helpful answers.

Frits, your response was not what i expected but makes total sense the way you explain it.

It seems to me that an eddy current dyno is capable of a wider variety of tests for efi and ignition tuning (step tests, drag tests, constant rpm test, etc) albeit with less accuracy and repeatability than an inertia dyno, which is best used to mimic acceleration as seen on a track. Is there a perfect middle ground... Something like the Dynojet with its heavy roller AND an eddy current brake? Or do the two units simply perform different tasks and therefore are best used for what they are designed for.

as long as you use an egt, head and case temp setup to replicate
engine heat load on every test.

Wobbly can you explain this further? So do you just monitor these manually and do a final comparison run once the heat build up in the engine matches previous runs?

[Yow Ling]

Thanks Frits and Wobbly, very helpful answers.

Frits, your response was not what i expected but makes total sense the way you explain it.

It seems to me that an eddy current dyno is capable of a wider variety of tests for efi and ignition tuning (step tests, drag tests, constant rpm test, etc) albeit with less accuracy and repeatability than an inertia dyno, which is best used to mimic acceleration as seen on a track. Is there a perfect middle ground... Something like the Dynojet with its heavy roller AND an eddy current brake? Or do the two units simply perform different tasks and therefore are best used for what they are designed for.



Wobbly can you explain this further? So do you just monitor these manually and do a final comparison run once the heat build up in the engine matches previous runs?

The Dynojet at Ashburton has exactly that an inertia drum and an Eddy current brake on the same shaft, I guess the software must combine the data from both parts to give a final reading. When I ran my bucket down there the Eddy brake has a temp sensor and was running over 200°C so how much of my 19hp went into there I dont know, must have been a reasonable portion

[Ocean1]

Yeah there is a market, but there is a reason a commercially available dyno is upwards of 10-15k. To build one "properly" would be a great cost, where ours are made of scrap metal and although be useful wont be as versatile as a professional unit. I would imagine that if we put our DIY units up for sale we may get a couple of thousand for it, but it is only worth what someone is prepared to pay for it.

I am looking into building a trailer to house mine, but that may be a while away I have run out of room!

For a build of 5-10 units I reckon I could make the mechanical components for maybe $4-5k, budget for metrology starts from perhaps a few hundred, reasonable range for about a grand, (sky's the limit, obviously). Guess it still boils down to more than most bucket racers would want to pay but I can see a club or even a couple of teams collaberating. In which case building one around a road trailer makes a lot of sense.

[Buckets4Me]

For a build of 5-10 units I reckon I could make the mechanical components for maybe $4-5k, budget for metrology starts from perhaps a few hundred, reasonable range for about a grand, (sky's the limit, obviously). Guess it still boils down to more than most bucket racers would want to pay but I can see a club or even a couple of teams collaberating. In which case building one around a road trailer makes a lot of sense.

the hard part is getting a decent roller $$ and then the software $$ all the other parts are doable by just about anyone

[dmcca]

the hard part is getting a decent roller $$ and then the software $$ all the other parts are doable by just about anyone

I priced up making my own inertia dyno not long ago... Solid roller ~350kg, ~400mm dia, 400mm long with stub axles, machined out of a solid bar was going to be $2000 for the material and about $1000 in machining. Plus transport between steel supplier, machinist and then me. Including the software/hardware that wobbly mentioned above plus a starter system, battery, steel frame, chequer plate covers, computer, monitor, fans, printer, etc, etc was going to be about $7000 from memory plus my time. Of course they can be made cheaper as others here have skillfully done, but then they're not suitable for resale as has been suggested in the last page or so.

After pricing everything up I found this one new for $8000 plus about $1000 freight, which seemed WAY easier than making one... http://www.daytondyno.com/webpage200hp.html

... Then I got side-tracked by an eddy current dyno... and that's where I still am today!

[crazy man]

I priced up making my own inertia dyno not long ago... Solid roller ~350kg, ~400mm dia, 400mm long with stub axles, machined out of a solid bar was going to be $2000 for the material and about $1000 in machining. Plus transport between steel supplier, machinist and then me. Including the software/hardware that wobbly mentioned above plus a starter system, battery, steel frame, chequer plate covers, computer, monitor, fans, printer, etc, etc was going to be about $7000 from memory plus my time. Of course they can be made cheaper as others here have skillfully done, but then they're not suitable for resale as has been suggested in the last page or so.

After pricing everything up I found this one new for $8000 plus about $1000 freight, which seemed WAY easier than making one... http://www.daytondyno.com/webpage200hp.html

... Then I got side-tracked by an eddy current dyno... and that's where I still am today!

it was 1700 for my 350 dia roller machined my self witch ended up taking 3 x longer than l thought . a 1000 would be cheap as if you got it done for that. it took 8 hours just to norl the dam thing! but if you could find one cheap its the way to go but if you can do most the work your self and to say you made it at the end of the day good on you

[Ocean1]

the hard part is getting a decent roller $$ and then the software $$ all the other parts are doable by just about anyone

I priced up making my own inertia dyno not long ago... Solid roller ~350kg, ~400mm dia, 400mm long with stub axles, machined out of a solid bar was going to be $2000 for the material and about $1000 in machining. Plus transport between steel supplier, machinist and then me. Including the software/hardware that wobbly mentioned above plus a starter system, battery, steel frame, chequer plate covers, computer, monitor, fans, printer, etc, etc was going to be about $7000 from memory plus my time. Of course they can be made cheaper as others here have skillfully done, but then they're not suitable for resale as has been suggested in the last page or so.

After pricing everything up I found this one new for $8000 plus about $1000 freight, which seemed WAY easier than making one... http://www.daytondyno.com/webpage200hp.html

... Then I got side-tracked by an eddy current dyno... and that's where I still am today!

Can't help with the transport, software (actually, maybe I can), battery, printer etc etc but a solid steel roller is a fairly expensive place to start if you just want mass. I also started making one, years ago, was a 3ft length of 12" line-pipe filled with concrete and a Caterpiller halfshaft. Ballanced up fine and cost me... can't remember but not very much.