air Nipple orientation on 914 airbox

So why isn't this little gem of information conspicious in the manual?

The fact that there are alignment marks available indicates that the placement is important.

Webby?

Regards.........Chook.

It would be useful to know what effect misalignment of this nipple might have on engine performance at WOT in short field takeoffs. Any clarifications gratefully received. Thanks, John.

The information is shown in Service Instruction SI-914-015:

Hi Andy and everybody,

Many thanks for fig 5 and SI-914-015 which cautioned "the counter sinking on the hexagon must be perpindicular to the airbox (see fig 5). This clarifies everything assuming that by the countersinking on the hexagon is meant the indicator dot? This would align the hole in the inner part of the nipple at an angle to the flow of air from the turbo rather than face on. My original guess was to align the hole on the inner part of the nipple face on to the air flow at the curved elbow. I will align as per the SI and see how things work out. Thanks again to Andy for the Service Instruction info. Best regards, John

The nipple detail is mentioned in latest Heavy maintenance manual  but nipples location and it's important function is missing.