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Coast Down losses c...
 

Coast Down losses calculation

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(@walter)
Posts: 245
Member
 

"lanzada 2": another car, many pulls, you can see an increase of drivetrain looses by increase rpm, that would make sense to me.


 
Posted : 08/08/2019 1:10 pm
(@walter)
Posts: 245
Member
 

why should it increase? have similar conversation some days ago.. i means, theorically, more power, more friction, heat,etc, but how does really affect more power in the real life? i means, you have same gearbox, same shafts, clutch, these parts have X inertial/drivetrain losses, no matter how much power you Will have these parts Will have the same interial. if you increase rpm, then you are getting more drivetrain looses, but in the same rpm? i'd say not, i get always same drivetrain looses. ive seen a lot of ppl haveing problems with tires, slippage, these factors Will give you different drivetrain looses, maybe i have a bit advantage by using hub dyno and all runs are controlled, same time for ramps,etc, for rollers if you have a bit slippage you are getting wrong drivetrain loses, or a deformed tire.. ive seen some tuners increase power just by drivetrain looses..i think thats a hacked real readings , using different gear Will modify too drivetrain losses. attached some examples of cars i tested. i'd say maybe if power increase affect , in my dyno it's less tan 0.1%..

"lanzada 1" : NA car, many pulls.

"lanzada 2": another car, many pulls, you can see an increase of drivetrain looses by increase rpm, that would make sense to me.

"lanzada 3" : a turbo RWD car..nothing special, just i think it's very important to get always same drivetrain looses readings.

"Lanzada 4" : Testing a turbo car with different maps, so different boost pressure. 

while im writing this, i noticed i only can upload only one image lool. i Will upload other images later.


 
Posted : 08/08/2019 1:09 pm
 Dev
(@dev)
Posts: 68
Member
Topic starter
 

No 🙂

Try it yourself - run a car standard, then run a car once it is tuned with more power.

You will see the drive train loss is identical - the percentage drive train loss actually drops.

 

 


 
Posted : 08/08/2019 12:55 pm
(@walter)
Posts: 245
Member
 

still no get it , sorry! if you know drivetrain losses calculated of your dyno, once you read drivetrain looses with the car, you can know percentage of drivetain losses have the car, then make the calculation, does it?


 
Posted : 08/08/2019 12:44 pm
 Dev
(@dev)
Posts: 68
Member
Topic starter
 

You misunderstand me,

Currently the calculation is ONLY related to roller speed and not the power output.  As power output increases, so does the loss.


 
Posted : 08/08/2019 12:35 pm
(@walter)
Posts: 245
Member
 

you have to calculate MOI of your dyno, once you do, you can read correctly coasting losses then you get WHP and HP.


 
Posted : 08/08/2019 12:30 pm
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