Power outputs at the wheels

[Oneofthegreats]

I did read through the info in the link & I'm still not a believer sorry.

I'm not here to cause an argument or a s#%t fight.

My reasoning is simple. A car that weigh's so much, make's so much power, can only go so fast & that's it.

You take a standard Golf GTI which weigh's approx 3100 pound's with a driver, fuel etc.
This car makes 147kw's (200hp).
The best recorded 1/4 mile by most magazines is approx 14.7 -15.0 ET with DSG. No MPH recorded.
Update: The lastest Motor Mag recorded a 14.6@97MPH

This work's out to be 98% spot on. The car is making a tiny bit more hp than indicated by the manufacturer by only approx. 15hp.

I'm not saying that all manufacturer's figure's are the be all & end all, as most German & Japanese car company's do underestimate there power figure's.

Also, that dyno graph indicates it's in shootut mode which can have a controlled drivetrain loss built into it, so it would be indicating the crank power/kw's.

If you go off the result's in the link, the GTI would be able to run very low 14's to high 13's.

[shaneth]

Rough figures

FWD : 15% - Fairly direct output to wheels, no change in direction if engine is mounted east -> west
RWD : 20% - Extra change in direction in diffs and weight of driveshafts
4WD : 30% - Same as above + weight of extra set of driveshafts and wheels

This is exactly what i thought as well. Then i confirmed it with a mate of mine who is a dyno operator up here. And as Sovereign said thats a rough guide as not all cars are the same but in general you are pretty safe with those figures.

[sydeos]

I think you are missing the point here.

Dyno testing results under common test conditions by independent testing body.

The results are only valid for the vehicles they have tested for output at the wheels on their dyno.

The only conclusions I and Autocar have made are that the VW/Audi group along with various other manufacturers appear to be understating there power outputs when looking over all the data that has been collected.

Not trying to start any fights that is all I am saying

[shaneth]

Leigh who are you addressing mate

And that site is interetsing yes but afaik rolling roads/ chassis dynos are ment for a tuning purpose mainly. Yes they do give you an indication of power especially when you do before and after results around a Mod. But they dont take all the loses into consideration. But once again afaik car manufacturers use flywheel dynos. And are much more accurate when it comes to power readings.

[Spyda]

Does it all realy matter?

I would have thought the only power that matters is the one that you put to the road. If i had 200hp and only 150hp at the wheels doesnt that mean i can only use 150hp...so isnt that the only one that realy matters?

Ive heard the veyron produces a great deal more then the 9 hundred whatever bhp its rated at but depends from car to car.