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Power sweep- RPM limiting from excessive brake application

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(@gasssed)
Posts: 24
Member
Topic starter
 

Hi all, 

I'm guessing that this is going to be one for our fearless leader and admin, Jostein, but please chime in if this rings a bell. 

I'm successfully using my Roadamatic II - after a few years of on and off again tinkering. 

I have it giving me repeatable power figures. Repeatable torque calculations and logging- which is great. 

 

The issue-

Using power sweep. 

I have the following settings-

- Start run at 2500rpm

- wait 2.0 seconds before sweep start

- Sweep rate 500rpm (but have tried 250, as well as 1000- just to be sure)

- Stop sweep at 7500rpm (have used 5000, 6000, 7500- no change)

 

As you can see on the runs, I'm not getting past around 4500rpm.

at this point it feels as though the brake is engaged to a point that the engine physically cannot continue to increase revolutions. 

This has occurred on 2 different cars- different engine combos, but both should be easily moving to 6000-7000rpm with no trouble. 

 

So what am I doing wrong here. will attach all runs from today as well as config file and a log file. 

 

 
Posted : 25/03/2022 11:34 am
(@gasssed)
Posts: 24
Member
Topic starter
 

config

 
Posted : 25/03/2022 11:37 am
(@gasssed)
Posts: 24
Member
Topic starter
 

log file

 
Posted : 25/03/2022 11:38 am
(@gasssed)
Posts: 24
Member
Topic starter
 

https://drive.google.com/drive/folders/1p92z3C1qSugz4EUkDYtqKtcSwVsBmvzO?usp=sharing

 

files (as they dont seem to be attaching)

 
Posted : 25/03/2022 12:47 pm
(@gasssed)
Posts: 24
Member
Topic starter
 

Is anyone able to provide some ideas? 

Really at a bit of a loss. I'm guessing it's going to be something simple in the brake control that I'm overlooking. 

 

I'm setting engine rpm via tacho, 3000rpm and lock ratio. So I'm confident in the reading there (and the drop off matches the tachometer and the reading on dyno readout)

 
Posted : 30/03/2022 8:47 pm
(@admin)
Posts: 1455
Member Admin
 

Hi,

I looked at the data. The brake setup is set to stop at 4500 RPM. Sure you have ticked the "Control brake using power sweep"-button? 

You can look at channel called RPM Target and look at it in the Results vs Time tab. You see it sweeps up then stops at 4500, the Engine RPM follows closely and as you say, also stop at 4500 RPM. 

There must be something fishy in the Brake setup. Can you send me your config file? The config file you attached used Manual Brake. 

 
Posted : 31/03/2022 8:56 pm
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