[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
RE: chipped S4
From: email@example.com on behalf of Dave Lawson
Sent: 26 February 1997 20:59
Subject: RE: chipped S4
Yes I think I do. The car was run up to full power on a 4 wheel rolling road
both before and after the fitting of the chip. The engine print out show the
BHP between the two and since I know the starting point (230) the gain in
charted power gives me the end point to a few BHP. The result was about 296.
hope that helps. Certainly no doubt about the road result.
The published hp numbers for the S4, 230hp or close, are usually flywheel
measurements where as rolling road numbers include driveline losses, which
some say is between 15 and 20%. Knowing these ground rules, what were the
before and after rolling road torque and hp numbers? Was the 296 BHP really
measured at the wheel or extrapolated based on some other wheel measured
They changed the Audi fixed open setting for the waste gate for an adjustable
one from Superchip to allow higher charge pressures into the cylinders. That
part took 5 mins and looks the same under the hood as before to all but the
very knowing in these matters. They then adjust the boost pressure in
accordance with the instructions from Superchip.
Given that the S4 controls boost pressure by using a frequency valve
which is connected to the actuation(lower) side of the wastegate, I don't
see the need for changing the wastegate to an adjustable version. If this
modification was done correctly(MHO), the ECU would be re-programmed
with updated boost profiles which would alter the wastegate frequency valve
duty cycle, thereby raising the boost pressure. Does your mod work?
I'm sure it does, but I don't think it was implemented in the hi-tech fashion
that they would have you believe... As QSHIPQ has stated, less and less of
this is rocket science.
1) As I explained earlier the car was tested before and after and hence my
'about 300' is extrapolated from the 230 starting point. Sure the 230 may not
be at the wheels and hence neither is the '300' but I think the relative
improvement is about right.
2) You might be right I only related what I saw and was told by the guy doing
the fitting and he certainly was not a rocket scientist but appeared a very
competent engine mechanic/engineer. He certainly appears to run a successful