|Quote, originally posted by Thinman61 »|
27% loss HP
That seems high no?
Not really. It's one of the reasons I was very suspicious of Neuspeed's dyno as it shows
much lower drivetrain loss and higher whp than I'd expect for an AWD dyno.
Perfekt: A better comparison than the Evo would be to know what a stock WRX puts down
on that same dyno. Do they know? If so, I want to know. There's hundreds of WRX dynos out there
to compare to so they make a good baseline. A typical stock WRX puts down 165-169whp
which is a similar 27% drivetrain loss. My *guess* is that a WRX on that particular dyno
probably is a bit lower than that, as a WRX has center diff and the R32 does not
so its AWD drivetrain loss should be somewhat less. But maybe they're closer
than I think in AWD mode.
As for it spinning the rollers at the same speed, once it's moving that should be normal.
If you hammered it in first gear from a stop though, the front wheels should turn
about 15 degrees before the rears start to move, and by 45 degrees (angle of this V)
at full power the rears should be turning the same speed as the fronts. An AWD system
with a center diff will also turn them at the same speed (ala WRX/S4). An AWD system with
only a center viscous coupling and no diff (of which are are a number of cheap mini-SUV
examples and more exotics like Porsche 911TT and Diablo)
will always turn one axle a bit slower than the other as the viscous fluid
never provides a full lock.
I have a strong suspicion that the Haldex system only needs a rotational difference
to apply the initial force on the clutch, but from then on, the torque
imbalance at the input shaft keeps it clamped. Think of it like your brakes.
You push the pedal down to engage the brakes, but then the pedal stops
and it holds the same force. No additional "pumping" is necessary to maintain
that force, thus no additional wheelspin will be detected. Haldex also
has an electric pump to prime the slave resevoir so it should be able to
initiate engagement even before wheelspin is detected, such as during launch
although I sure that it still needs that torque imbalance to provide full lock.
As for the numbers themselves..
Folks have to keep in mind that as soon as the R32 is out of first gear the Haldex
clutch will be disengaged most of the time and total drivetrain loss will decrease
significantly. The above numbers represent the worst case scenario.
Perfekt, did you get a chance to try the pulling the handbrake trick to disengage Haldex
just to see if it works?
Modified by Daemon42 at 2:10 PM 2-13-2004