The conventional wisdom is to use LDRXN to limit req boost. But it comes with a lot of (sometimes unexpected) side effects; the load -> boost path can be confusing and difficult to understand, in particular, its sensitivity to IAT and VVT angle.

Wouldn't it make more sense to simply use KFLDHBN instead and raise LDRXN out of the way? It can be tuned directly off of a compressor map. It is not sensitive to IAT (other than the obvious effect by axis), or VVT angle. It compensates for altitude naturally. It is a 2 axis map which allows for more flexibility (not to mention possibly easier map switching via dynamic axis change, etc.).

It seems to me the only reason LDRXN is exclusively used to limit boost in tuned ECUs is because aftermarket tuners discovered that map early on via reverse engineering, before FRs became readily available, and it has to be raised anyway.

Comments?

Certainly a comment I am actually surprised this is brought up only now. This method is actually one of the first things that came to my mind when I was trying to understand ME workings with ME7.9.10 as my case study. There I raised LDRXN counterpart (there it is done by a torque limiter, not load, called MDMAXNMOT, but it is almost immediately recalculated to load) so that the max load would first hit KFLDBHN instead of the torque limiter to get the maximum factory safe power (under the assumption that whoever came up with LDBHN knew what he/she was doing). No ill effects whatsoever. On my ECU MDMAXNMOT is waaay above what the engine / turbo can do in very low revs, the actual boost meets requested only after 2000 (take into account that this is a tiny turbo setup). So I do not see any reason why MDMAXNMOT cannot be maxed out and boost controlled by LDBHN. And another map that limits load according to IATs, because on this ECU LDBHN is actually 1d and only RPM dependent.

Short version: this is what I actually did and it worked fine

You should use both, that's what they are there for, it's pretty simple!