dr20t wrote:Twinkle wrote:QuarterMile wrote:I do, its a 2.2 Na though, so I don't really know much about Libs with power.
Is that really all they produce at the flywheel?
Most manufactures figures are flywheel.
All of them are
To answer original question - drivetrain percentage loss for manual is roughly 20%
25% for an auto depending on its age (due to Convertor and clutch pack slip which will get worse as time goes on and thus put less power to the ground and increase the above losses)
It also depends on the load you're talking about. At low load, the losses are alot higher (especially for an auto Subaru due to the transmission computer not giving full torque Convertor lock up until higher load / higher gears)
Example - 2nd gear in a 5eat will only ever give you about 80% torque Convertor lock up unless you have an aftermarket transmission computer, 3rd will give you 100% depending on requested torque and load, as will fourth and fifth
Hope this helps
Mick
Very well said mate
jslayz wrote:Surely.......
The loss through the drive train is a fixed value.
The weight of all components plus the friction of all bearings and shafts rotating in fluid = drivetrain loss.
This can only be a % after you know the cars power level.
If your car has a different power output the % will be different......
J
There is a running debate on this sort of thing. I've been told & have read that if there is a drive train loss of say 100kw on a stock standard car, then with mods, the loss after the car has been modified is the same. IE: Not a percentage... For example 353kw stock car = 300kw ATW's... Exhaust + Tune gives you 400kw at the flywheel, therefore new power at the wheels "should" be 347kw.
I don't 100% agree (Although there is a degree of logic to it) on this as there are so many variables that can effect this & would suggest this is why a drivetrain loss as a percentage is commonly accepted.
On another note, a rolling road dyno also suffers from inconsistencies from tyre rolling radius, tyre pressures, etc etc etc. HUB dynos, which will obviously give you a higher power reading as the it removes the tyre & wheel variables, is said to be a more accurate way of reading power - Short of actually having an engine dyno of course... Then we start another debate of how to convert this into ATW's power, but this can be done with a good degree of accuracy, just don't ask me what the formula is
Oh, & for all you 2.0T Gen 4 auto drivers... You have approx 115-120kw ATW's in a stock car... Huge loss considering it's 180kw at the fly / engine, which is a percentage loss of approx 35%... So show big respect when you see these cars pushing out 200kw ATW's plus!
Posted: Thu Aug 01, 2013 12:34 am
Do you drive a Liberty? Because I've got bad news if you do...