To pick up an old thread, I know a case of an induction leak which really messed up the way the engine was running. All it was was a intake pipe gasket which came out.
Can anyone explain why induction leaks have such a powerful effect? There is a huge amount of suction, the air path from the air intake is a large duct, yet a tiny gap like this can really screw things up.
Induction leaks are a go-to fault when any aeroplane is running like sh-it. Changing gaskets and induction hoses/rubbers are well worth your time if you are not sure of when they were last done.
Indeed; however my Q was why does a small gap cause such havoc?
It throws off the fuel-air mixture locally, only affecting a few cylinders or one side of the engine, for those engines not having spider induction tubing.
The GAMI-leantest flown at two different altitudes (say 3000ft and 6000ft) should show the same ‘pattern’ of cylinders peaking. If the pattern is different then an induction leak is to be suspected. At high manifold pressure (say close to ambient) less effect is observed from induction leaks than idling where the delta between outside pressure and low manifold pressure inside the induction tubes will amplify even a small leak.
