[Biturbos4] s4 power output

Robin Gibson robingibson at cowanlinn.co.uk
Wed Mar 24 08:01:04 EST 2004


I have been worried about the turbos on my 1999 s4 6-speed for the last few thousand miles; lack of power, lag, noises etc.  The dealer couldn't find anything, so I took the car to a local rolling road yesterday.  After 20 seconds the technician noticed that the engine was running dangerously lean, and he pointed the finger at the airflow meter.  This was replaced and the car was re-tested.  "Good news, your problems are solved" he told me, and passed me the dyno plot (attached) showing 220 bhp at the wheels at 5000rpm.  This seems about ok for a theoretical output of 265bhp.  Problem is, the engine is chipped (abt) to a theoretical 300bhp, so I expected to see perhaps 260bhp at the wheels.  I was running 95 octane fuel (which the technician gave me a bollocking for) and the air filter has been in for 10k, but I can't think these would account for the loss in power.

Can anyone see from the plot if there is anything obviously wrong?  Does the boost look reasonable for a stage 1 chip?  Or am I just expecting too much?  I'd appreciate any help or comments you can give me - seems this car is destined to keep me worrying some more.

Robin Gibson

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