williegoat
Well-known member
It's raining here in the desert....
I have a '99 S3 with a Buell race ECM, Forcewinder intake and a White Bros. Muffler, with 24,000 miles.
Observations:
It runs a bit rough at low RPMs and small throttle openings, steady cruising in the first few gears. I have put in fresh plugs, a new O2 sensor and TPS. It does not throw any trouble codes and the AFV stays between 92 and 96.
The crankcase breather is routed to the intake, and if I let it idle for too long, I will find a drop of oil on the bottom of the air filter. I don't think this is excessive blow by for an engine with that many miles and it doesn't smoke, use oil or foul plugs.
I just had it emission tested (idle only test here in AZ) and though it passed, the Hydrocarbons were just barely below acceptable standards. This and the low AFV lead me to believe that it is too rich, at least under idle and cruise conditions
Questions:
White Bros. Muffler:
I know that a pipe like this will not maintain good flow velocity at low RPMs and therefore probably does not properly scavenge the chamber.
Could this be enough to cause an overly rich condition and poor low RPM/small throttle performance?
Crankcase breather:
Could the oil mist in the intake be enough to fool the O2 sensor and cause a high HC reading on the test? Is this the reason people do the breather re-route?
I know that data logging and tuning are the final answer, but not until I change the muffler and solve all of the little issues.
I have a '99 S3 with a Buell race ECM, Forcewinder intake and a White Bros. Muffler, with 24,000 miles.
Observations:
It runs a bit rough at low RPMs and small throttle openings, steady cruising in the first few gears. I have put in fresh plugs, a new O2 sensor and TPS. It does not throw any trouble codes and the AFV stays between 92 and 96.
The crankcase breather is routed to the intake, and if I let it idle for too long, I will find a drop of oil on the bottom of the air filter. I don't think this is excessive blow by for an engine with that many miles and it doesn't smoke, use oil or foul plugs.
I just had it emission tested (idle only test here in AZ) and though it passed, the Hydrocarbons were just barely below acceptable standards. This and the low AFV lead me to believe that it is too rich, at least under idle and cruise conditions
Questions:
White Bros. Muffler:
I know that a pipe like this will not maintain good flow velocity at low RPMs and therefore probably does not properly scavenge the chamber.
Could this be enough to cause an overly rich condition and poor low RPM/small throttle performance?
Crankcase breather:
Could the oil mist in the intake be enough to fool the O2 sensor and cause a high HC reading on the test? Is this the reason people do the breather re-route?
I know that data logging and tuning are the final answer, but not until I change the muffler and solve all of the little issues.
