Q&A Forum
Quite regularly I get a spike of reatardation at the end of a run, dyno in question is a bosch FLA 203.
I realise I might be able to prevent this by turning of the brake just before the end of a run, but in between monitoring datalogs, afr's etc. It's quite a hard job to get it right. Alternatively I could change my end of the sweep to exactly the rpm I'm after, but I'm not always able to stop exactly at that rpm.
I reckon It's due to the current of the brake not being able to discharge fast enough so it's still braking a bit, but I cannot change that without using a brake controller like the new HS-PWS brake controller from Sportsdevices.
In the past I've worked with a Maha dyno which just neglected the last 500rpm after a run and calculated the rest of it based on the rest of the retardation run. Is there such a function in yourdyno or would it be possible to add it?
Alternatively the Maha has a function to automatically disable the brake when, for instance, torque all of a sudden drops 50nm, so we won't have to turn off the brake manually when transitioning into the retardation.
Picture added 🙂
Regards,
Arthur
Dont worry, older yourdyno versions, that spikesadded to the final run, then was a big problem, right now, if you have a bit of that spike at the end , it does not apply to the final test.
What mode are you using in your dyno? normally brake get off once run is done automatically.
I had some problems with that spikes in the past, because added to the final run and of course added some power to the final run, in my case wasnt to much added, like 3-5hp , i have to say too it's about how good you make clean runds, it's all about practice more and more, i found that improving a bit more PID control you can improve it a bit but since Jostein upgraded by fixing that spike doesnt apply to the final run, then dont worry. its about Eddy brake and some parasitic currents that your power supply doesnt absorb faster. HS-PWS from sportdevice looks really good, but i dont know how big difference would affect to the final run really.
Maybe try this: car: 2000rpm - 7000rpm .
Put in the mode : 2000- 6950rpm and so. try and make more test until you dont get that spike.
Indeed the spike is due to the power supply not turning off fast enough.
But as Walter says, in newer software versions the start of the retardation graph is ignored (just like you mention Maha does) so this does not show anymore. You should not need to play with the end RPM either. Are you running the latest software version?
No I'm not, I don't have Wifi in my company building so have to do it off my phone. Will do that first and try again. Sorry to bother you with something that simple 🙂