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Vane 4000 dyno upgrade

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(@bmgjet)
Posts: 362
Dyno Wizard
Topic starter
 

It still does it, Cant figure out how to stop it. Im using automatic start/stop logging, All lines up with my RPM sweep start and stop rpm. Even tried holding it at the end of the run at a flat line but didnt make any difference.
So just made a little program up that opens the CVS file and trims a few lines after peak RPM off the end of the file.
Using manual start/stop works fine tho but thats imposiable to use when dynoing a FWD car since you need both hands on the steering wheel to keep it pointing straight.

Went though setting up the MOI as the video shows.
Ended up with a MOI of 31.5 and the line up and down perfectly overlay.
Then turned the corrections back on and did another run. Says my power is 380HP where it should only be low 200s.
So dont know what I did wrong. Even using HP correction -25% and torque arm length of 1cm still ended up in the high 200s hp.

So just left MOI and retarder corrections turned off. Then entering the torque arm length slightly wrong gives the sort of reading Im after that lines up with the old software since I want runs to be compariable to there old dyno sheets or close too.

50cm instead of 48.5cm.
Gave me a reading of 209.80HP. Old software gave a reading of 210hp.
Both calibrated with the same weight and back to back runs.
Having the correct arm length gives a reading of 199hp.

The bug in the brake control is quite a pain tho. Today it happened almost bang on 15mins where the brake output out of the controler just gets stuck on 0V. Unplugging and replugging in the USB fixes it for another 15mins.

Have found a tempory work around for needing speedo reading for calibrating speedos.
Change the RPM guage to digital. And using a gear ratio of 0.10 lines up perfectly with 100rpm to 100kph and 50rpm to 50kph.

 
Posted : 18/08/2018 3:59 am
(@bmgjet)
Posts: 362
Dyno Wizard
Topic starter
 

Will make do until problems are fixed in the software.

 
Posted : 18/08/2018 11:34 am
(@admin)
Posts: 1460
Member Admin
 

Bmgjet, I have been trying to replicate your issue of logging not stopping, but have not been able to. 

If "Enable correction for frictional losses from retardation data" is off, then the logging shall stop when the engine RPM is higher than the last point on the brake curve (assuming you do an RPM sweep up). Note that the run length does not matter, even if the run is longer than the brake curve duration, YourDyno will wait until the end RPM is reached before turning off logging. Could it be that the end rpm is not reached? Zoom in on the graph and compare with the brake curve end RPM. 

On the MOI. A figure of 31.5 is very high, roughly what is the weight of your rollers? To reach that figure you need minimum around 1000kg (depending on the diameter, of course). If this MOI figure is wrong, and your lines still lined up like you say, the reason is likely either the gear ratio is wrong or the Number of Pulses per dyno rev is wrong. The latter is a common problem, people enter a wrong "pulses per dyno rev" number, then let the system do a gear ratio calculation. The RPM will then show correctly, but the gear ratio will be wrong, and the results are wrong. Of course it can also be that the calibration of the load cell was wrong or the load arm length was set incorrectly at the time you did the MOI testing. 

I have seen the bug on the brake control very occasionally. I will try to find a way to reproduce it consistently so I can correct it.

 
Posted : 19/08/2018 12:02 pm
(@bmgjet)
Posts: 362
Dyno Wizard
Topic starter
 

What ever you changed in the update today fixed the tail on the dyno graphs.
Getting a big swing on the start now, Probably with how iv got it set up so will need to have a play with that. Brake holds it at start rpm but drags the rpms down 200rpm below start point then run starts so most likely my PID settings.

Dyno bed has 4x 300kg rollers so would be about 1200kgs.
2 of the rollers are on the back of the dyno and unconnected to anything. Other 2 rollers are on the front and joined together then go to the retarder.
MOI probably wont work properly in my case since depending how you tie the car down it can climb up on the front rollers only so rear 2 rollers dont spin.

Got first tune done on it today outside of playing with my car on it. Had to use my program to make a nice enough graph to give to customer.
One thing that is a bit of a pain is you cant put spaces in the comments section.
Also a bit of a pain having to retype it all each time you start a new run. Would be nice if it remembered the last information you put in the drop down box.
And I can see my dyno dir getting quite clutted since there isnt really any order how it saves the csv by default.
If it made a new folder for each unique name would keep it a bit more tidy.

 

------

Blue line is after running though my program.
Purple is before as the log caputed it.

 

 
Posted : 20/08/2018 10:15 am
(@bmgjet)
Posts: 362
Dyno Wizard
Topic starter
 

Have attached a copy of my program.
Any one feel free to use and share how ever you want.
Iv turned off the convert to speed and kw since that wont work on any one else setup since since it uses hardcoded values of my dyno.

 
Posted : 22/08/2018 2:18 am
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