Wheel Kw's to flywheel kw's

[gtfpv]

20 % HAS ALWAYS BEEN THE ACCEPTED RULE. FOR A MANUAL. . this is a rule of thumb for all engineering design . an 80 tonne shackle is capable of lifting 100 tonne safely.
friction losses of rotating gears equate to 20% . it doesnot get better with modern times, it's a fact.
i was told during my apprentiship is the late 80's that all machines with rotating and recipricating parts lose power due to linear forces on rotating parts and surface friction. which equates to a measured 20 % loss on a vehicle driveline.
obviously the more gears the more friction loss. so a 4 wheel drive would lose more.

[prydey]

so a stock ef/el falcon should have about 125rwkw based on your theory. i've never seen that and i never will. facts speak a lot louder than theories. also based on a 20% loss stock ba sixes would be around 143rwkw. also a little optimistic if you ask me but not as far out as earlier cars.

drivelines have become more efficient in modern times, namely gearboxes.

[Badcooky]

Prydey because ford tell us that the EF/EL had x kilowatt did it have it or does the one Ford put together for analysis have that kw.

[burnz]

Originally Posted by TUF240

but then if autos lose more power? y are they faster than the manuals down the quarter? in stock form that is? not bringing modded cars into it..

an auto has tourque multiplying factor's
manuel's do not

[asusdragon]

also over time the eninge become less efficant, so more loss of power from the start

[prydey]

Originally Posted by Badcooky

Prydey because ford tell us that the EF/EL had x kilowatt did it have it or does the one Ford put together for analysis have that kw.

lets assume then that most ef/l falcons stock have somewhere around 100 - 110rwkw. based on forum members results this would seem pretty close. using a 20% drivetrain loss this would put the flywheel kw around 130 - 135. are the engines really going to be 20oddkw down on power. i had an el in 2000 so it was 3 yrs old and about 80 000km's so you wouldn't say the motor was tired, and yet in stock form it only achieved a touch over 100rwkw.

most stock vt/vx gen3's are around 160 - 170rwkw from a 220/225kw motor. most stock xr6t's are around the 180rwkw mark from a 240kw motor. most xr8's are around 200 from a 260kw motor etc etc. based on all these figures which are very average, 20% loss seems too little but 30% seems too much. all engines will vary from factory. there are freaks and lemons but to assume they are all down on the quoted factory figures is a bit out.

like i said a lot earlier though. does it really matter except for bragging rights. its just a number and maybe the difference between telling your mates you have cracked the 300kw with your motor, or fallen 15kw short. maybe a little of the mine's bigger than yours syndrome.

there's also the ageless debate over the accuracy of a lot of dyno's. ive seen quotes of up around 180rwkw in a ba but backed up by a 15sec 1/4 mile time, or 170 odd in a e series with a 14.4 1/4 time. i'm no expert but to me, one contradicts the other.

this could go on forever. how long is a piece of string?

[3vXT]

Modern cars do quarter mile times around 14.5 seconds.

Thats a pretty stupid thing to say because there are far to many variables, far to many cars and drivers and other things that make cars different from each other. I do realize that there are less variables in a gearbox, but suggesting that you can ACCURATELY work out drive train losses over hundreds of different gearbox's with a blanket 50kw or ANY percentage figure is just as stupid.

Vague generalisations FTL.

[Steffo]

The closest thing to a true global standard would be 18% manual, 20% auto. However, it differs from country to country, with Australia and its lot of dyno crowd inflating it big time (people on this forum have told me to expect 35% drivetrain losses before... lol!).

The truth is... wheel kW is a bunch of hooey. It means nothing, never did, never will, end of story. Its a gimmick to make some money off people in the aftermarket game. Chassis dyno's are excellent tuning devices and nothing more. Want a real indication of how powerful your car is? Take it to the strip stock, then take it to the strip after mods.