I know I'm kind of back seat driving here, but I still think the crank for the brake is a bad idea. A nice long lever that you could pull from a distance seems like the ticket.

Feel free to ignore me, I'm just spitballing here..lol

FAILURE -------------- the way I see this right now is that a brake dyno is no good for a CVT drive.
You must run an inertia dyno. No chance in hell a brake dyno will work without doing damage. JMHO.
At this point I think I will have to kill this project but I did get some baseline data that I will share here.

Data, please bear with me while I explain the numbers.
I managed to pull 3 data points that were useful. The rest were junk because of glare from the shop lights on the Engine rpm gauge, vibration of the rig causing unreadable torque readings, smoke in the shop from the burning belt.

Torque 171 ft/lbs at 6780 Engine rpm at 377.5 axle rpm
Torque 204.4 ft/lbs at 6740 Engine rpm at 339.3 axle rpm
Torque 231.5 ft/lbs at 4800 Engine rpm at 278 axle rpm
First line: 30.7 HP
Second line: 33.01 HP
Third line: 30.63 HP

What does all this mean and how did I come up with the HP number.
1) My brake dyno has a torque arm that is 2'6" from the shaft to the load cell. So this means you multiply the torque by 2.5
2) So now you figure out HP of the Engine --- the formula is rpm x torque divided by 5252

So lets take line one for an example:
A) 171 ft/lbs x 2.5 torque arm is 427.5 ft/lbs of torque on the oddy. (I can hear you guys laughing so just sit there and have another beer while I explain it later in this piece)
B) Axel rpm 377.5 x 427.5 ft/lbs torque divided by 5252 is 30.7 HP

CVT ratio: Axel rpm must be multiplied by 10 to make up for the 10/1 gearbox ratio and then you take the Engine rpm and divide it by the updated axel rpm to get a CVT ratio.
Axel rpm 377.5 x 10 (gearbox ratio) equals 3775 rpm. Engine rpm 6780 divided by 3775 is 1.79 CVT ratio.
So the total gear reduction at this particular point in the test was 10 x 1.79 = 17.9/1 total reduction.
This is the reason the oddy has such incredible torque but it's also the reason an oddy will only do 63 mph.
A corvette will do 150 mph because the gear ratio is real low (3.9/1 or 4.11/1) and it has 500 HP to keep it there. If you put a transmission in it with 17.9/1 reduction it ain't gona do 150 mph anymore but with 500 HP it would be able to rip anything apart. That's how this all works.
Here is a good read that explains what I just said but you have to read all of it to understand it: https://tech.corvettecentral.com/2015/1 ... formation/
CO

Edit: Based on what I see here the Torque/Hp magic number is 6700 rpm for this Engine.
Edit again: If someone see's something wrong with the math (Adnoh ?) feel free to shoot at me.
CO

Congratulations! I didn't see any rapid unscheduled disassemblies!

Still a neat project, and cool to see.




I bet that was a hell of a stink in there, with the brake pads and belt both getting toasty.

Bug: No I don't run any fans because we don't run it long enough and I don't warm up the Engine either.
Gro: No stink from the brake pads believe it or not. The brake system is massive and the oddy just don't have the power to really heat this thing up.
Lid: I went with the crank because it would hold position at all times, unlike the handle.
CO

I know this data is good because I just looked at an email that Lee sent me a long time ago.
I asked about HP and Torque of an oddy. The numbers are good.

Keep in mind that this is not a totally stock oddy.
This Engine is the one that has the welded piston in it, a homemade cylinder head, K&N fly screen filter (no sock) and a cheater pipe as Hoser calls it. A cheater pipe is a stock pipe that has been cut apart and the guts removed.
CO

Looks like you got the actual numbers you were looking for, so not a total failure.

I know you're over this dyno, but don't bin it quite yet. In your spare time, or when your bored, give my long brake lever some more thought.

If all you had to concentrate on was pulling the lever, you could watch the belt and release the brake if you started to see it slipping. I realize this would require moving the master cylinder or the whole dyno to the other side of the oddy, but depending on how you did this, it might not be much work.

Another suggestion I made earlier, If the dyno were bolted down and vibrated less, would that fix the reading problems?

The way I see it, your results are proof of concept.

1) I'm done with this dyno because it's just to hard on a CVT drive system. It's just not made for it.
2) Lever: I know what you are saying but I just don't like the idea because I can't lock a brake position accurately. But it would be a good experiment if I continued with this thing but I'm done.
3) Vibration: It's not really a big unsolvable problem. All I would have had to do was put some foam between the torque arm and the frame that holds the load cell.
CO

One of the things that may be useful is that even though this data was pathetically small, the oddy CVT system appears to run between 1 to 1 and 1.8 to 1 at a varied rate.
It's possible this system runs between 1 to 1 and 2 to 1 varied rate.
Not sure if anyone can use that info.
CO

I have been very bored the last few hours so I started looking at old stuff on my computer again. Decided to play around with those data points to get some more information.
What I wanted to know was 1) cvt ratio and 2) oddy torque at the crank 3) HP
I know that I said it was running at 1.79 to 1 but that is on the first data point.

Here are the results:
Line 1 data point: cvt ratio 1.79 to 1 torque at the crank 23.8 ft/lbs 30.7 HP
Line 2 data point: cvt ratio 1.98 to 1 torque at the crank 25.8 ft/lbs 33 HP
Line 3 data point: cvt ratio 1.72 to 1 torque at the crank 33.6 ft/lbs 30.6 HP

I'm pretty sure I did this right because it's very very close to what Lee told me in a PM.
Also of note is the 1.98 cvt ratio. Clearly these units run at 2 to 1 ratio.
Therefore the total ratio is 20 to 1 over all.
CO

you should get some sort of data acquisition system, put a RPM output on the crank and on the driven clutch. some of the chip tuners and o2 readouts have that option built in, it's only money