Hi,

For a hydraulic dyno with manual brake control, you do not need 200 pulses per second. Anything above say 10 pulses per second is fine. 

To your question: It is very important that the pitch is constant, otherwise there will be noise on the RPM. I do not recommend making a trigger wheel by hand, you need a CNC machine or just buy one off the shelf. A steel timing belt pulley works well. You may need to remove every other tooth or so.

If you can, I would change the gearing so the pump runs faster, but that's maybe not possible for your kart setup. With higher pump RPM you can go down in pump size (cheaper). 

I Will make dyno with automatic brake control. Im going to buy a Steel timing belt pulley. I have found one with 68 tooths and 5mm pitch, look The link below, in your opinion this pulley can work with your rpm sensor? 

pitch.  https://m.ebay.it/itm/Pulegge-dentate-per-cinghie-positive-XL-037-Passo-1-5-5-08mm-in-acciaio/142668151387?hash=item2137af3a5b:m:m9bF-Rbm0BLbej_U7InaVZg&varId=441651973554

Thanks aalot

Eric

Hi,

The trigger wheel in your link looks too to be 5mm wide, does it not? Make sure it follows this spec:  http://yourdyno.com/the-trigger-wheel/

It does not look like it will follow the spec from the photos. But it was very cheap!!

You can go down to as low as 20 pulses per second and still have good auto brake performance. 200 pulses per second is really only needed for inertia dynos, or if you insist on having 100 RPM updates per second. It's a bit overkill! 

Ok, is necessary that wheel Follow the spec in photo. I think it is so difficult find a wheel that Follow these spec. Could you suggest me any website to buy the wheel?

Thanks 

This should work if you grind off every other tooth: 

https://uk.rs-online.com/web/p/timing-belt-pulleys/0183619/

Sorry, can you explain me wich other tooths are to grind off?

You are very patient and kind

Sure! You just take an angle grinder and remove every other tooth. It can be done by hand, no problem.

Do you mean to remove the rim circled? Or the thoots of wheel?

Sorry but I can not understand which other thoots i should remove

Thanks 

Eric

Do you mean to remove the rim circled? Or the thoots of wheel?

Sorry but I can not understand which other thoots i should remove

The issue with many wheels is that the distance between the teeth is too small. To fix this, you remove every other tooth. Then the distance between the teeth will double. You can remove the rim too, but it is probably not necessary.

Hi jostein, what do you think about this wheel? 28 thoots. 

For automatic brake. It's only to polished.

Looks great!

 The dimensions of theets in photo mustn't be followed with extreme precisione correct?