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Dip in the hp & tor...
 
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Dip in the hp & torque curve...why

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(@christopher-pfoltner)
Posts: 11
Member Customer
Topic starter
 

I'm running a small single cylinder engine on a hydraulic disk brake dyno.  The engine is an LO206 sealed engine.  Briggs, provides factory torqu/hp curves.  So I know what it should be.  My curves look like theirs except at about 3500 RPM I see a dip when I make a run.  I have tried starting at high RPM and pulling it down with the disk brake and tried starting at low RPM and loading it, then unloading it.  On chart below you can see the dip; however, you can also see that when I was working it up to high rpm, it did in fact make hp/torque at 3500 RPM.  However, when I sweep, I get the dip.  Any thoughts on this?  Resonance of the dyno maybe?

Any help would be appreciated.

Thanks

Chris

https://drive.google.com/file/d/1f6CuI4OilZ_ePCgjnsLnsEYs52P5MqYO/view?usp=sharing

 
 
Posted : 09/04/2022 12:10 am
(@admin)
Posts: 1457
Member Admin
 

Hi, can you post the csv file?

 
Posted : 09/04/2022 12:14 am
(@christopher-pfoltner)
Posts: 11
Member Customer
Topic starter
 

Here it is:

https://drive.google.com/file/d/1rqbsUmZtNbhRAnq8WxYtxBfHbAC9Nswx/view?usp=sharing

If there is another way to post this, let me know.

 

Thanks.

 
Posted : 09/04/2022 12:22 am
(@christopher-pfoltner)
Posts: 11
Member Customer
Topic starter
 

Here it is:

 

https://drive.google.com/file/d/1rqbsUmZtNbhRAnq8WxYtxBfHbAC9Nswx/view?usp=sharing

 
Posted : 09/04/2022 12:23 am
(@christopher-pfoltner)
Posts: 11
Member Customer
Topic starter
 

Tried to post and it didn't work.  I messaged you with it, but not sure if that went through.

 
Posted : 09/04/2022 12:26 am
(@admin)
Posts: 1457
Member Admin
 

Hi,

I removed the start and the end of the run so you are left with only the sweep. Here it is, it looks ok apart from an area around 3600-3700 RPM, where I believe there is some resonance or something. If you send me the raw file I can take a look. Send to jostein@yourdyno.com

 

 

 
Posted : 09/04/2022 10:32 am
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