Hi Dave ,and welcome to the forum, what manual valve is on the STUSKA model 90 engine dyno you have ? How does it operate/work ?

@mach_1 its currently setup using a 3/4 globe valve

Hi , Dave , so the stuska originally fitted with that 3/4" (19.05 mm) Global Valve ?

What does the Global Vale look like inside , shape of the orifice? Do you have a picture ?

Also i gather the Global Vale  is fitted on the discharge side of the dyno?

@mach_1 correction I'd assumed it was a globe valve, I've taken it off and its a Lunkenheimer needle valve. 

Correct there is another valve fitted to the discharge hose.

Valve

That's  more like it , how do you find the adjustment  went manually loading and unloading the engine when performing tests  ? 

What does the other valve look  like on the inside ? 

There should be no reason why you couldn't put a stepper motor on that lunkenheimer needle valve .

@mach_1just got the dyno, waiting on the yourdyno kit before testing any suggestions on the brand/ type of stepper motor?

So i take it you have not never run it before ? In manual form ?

How many turns of the valve handle/wheel from fully open to fully closed. How easy does the valve turn ? 

Brand ? They all nearly 95% chinese made , nema 23 stepper motor high torque should be plenty big enough for that valve size , you going have to do some thinking/calculating to work out speed response times. Might involve some gearing arrangements between the stepper motor and valve.

https://m.youtube.com/watch?v=mG2Q48l2V7A

Valve takes 5 turns to fully open.

Cheers for the video.

Are you running a water dyno? What valve setup are you using?

Hi Dave , that's not my H&F G90EH ,purely for example purpose of the size of the stepper motor and the gearing used and the 10 second  dyno pull from WOT low rpm through a sweep of to 10,000 rpm normally aspirated engine test. The H&F G490EH is rated at over 1500BHp @15,000rpm.

i have a H&F GB4_1 and used the standard valve that come with the dyno works beautifully on my setup.

Now you have some thinking to do " 5 full turns " from open to close ..... and you mentioned you have a outlet valve you will need to make adjustment  for the right sensitivity  per different individual engine test. 

I strongly suggest you get your stuska90 hooked up toa engine in its manual form and see how it responds/functions ? Cause how i understood you Dave you just acquired  this dyno and haven't  run it yet ? Yes  or  No ?

The stuska 90 is a small water brake from memory  , what BHp / toque @ rpm's is it capable too hold ?

No, I haven't run it yet, waiting on the yourdyno kits to arrive.

I've got a new globe valve sitting around, so I've decided to design a new disc that I'll get made up so I can get a linear opening of based upon 4 turns.

I'll use the stepper motor like you have suggested and should hopefully work well.

The stuska 90 is good up to 100HP I think but we are only testing 2 stroke engines at around 30-40hp.

I've seen the recommended response time from open to close is 0.5 seconds which I should be able to achieve.

I am retrofitting an old GoPower DA512 dyno currently.  In the video below you can see that I used a stepper motor connected to a 1 1/2" globe valve.  It seems to work good when I manually control it and I can put a load on the motor.  I need to make a new shaft to hold the speed sensor pickup to get a speed reading at the moment.  Once I get that done I will video and show how it works out.

https://www.youtube.com/watch?v=gXS2ehSDi0w

@dave78 I'm in the same boat as you, Stuska 90. I was going to change over to some sort of linear ball valve but I decided to just put a stepper on the original valve and see how I go, I figure there's nothing to lose. I'm keen to see how yours works out.

@james-meyers

Currently waiting on new valve discs to arrive from China, I've worked out a new curve for the valve disc to get a linear opening.

I'm getting two types made one based upon 2 turns and one based upon 4 turns from fully closed to fully open.

What size stepper motor are you running?