Hello dear Members,

I have a situation with one 1.8t it the car is pretty much stock.
Rear lambda is disabled as well as secondary air injection.
The thing is that when the aftermarket manifold is fitted the car is not holding idle.
As far as I know KISRM(out of FR) is the one that needs to be changed.
On the other hand I have read on here that KIRSM is a load filter nothing more.
The new Manifold is twice the volume of the stock. I have calculated KIRSM for the new manifold but nothing changed.

here is the link of the Aftermarket manifold:

https://www.stwtuning.de/tuning/performance/ansaugbruecken-verteiler/ansaugbruecke-inkl-einspritzleiste-volkswagen-1-8t-schwarz_51311_24041?fbclid=IwAR0KHo5YiSKoKeK23hmOzl2W-YwNY-q-JmwsfohoWsiJ0Gli6RSVwOub75M

It would be nice to hear your opinion on this strange behaviour.

Logs are attached.

Probably by solving the massive boost leak he had...
KISRM has nothing to do with "holding idle".

If the only thing that you swap is the manifold and the car does not idle anymore then you have a giant boost leak somewhere.