[Showdown]

If you intend on using MAP to tune (speed density) then you must do a few things:

1.) make sure that the vacuum readings come from after the butterflies. This is absolute and not negotiable.

2.) collect all 6 hoses from each ITB and gather them into a common manifold, even better is to group 123 into a manifold and 456 into another one and then group those into a third. Wanna be even better; fill each manifold with open cell foam to further limit pulsing.

With that (after you balance your ITBs) you'll have a really stable and even MAP signal that will allow you to tune with Speed Density.

If you're on software that allows it, you can scale your VE table, or use dual tables like I did: one table for 30-80kpa, and the second for 80-100kpa. this gives you really tight and precise control over the active range of the MAP signal (80-100 in my case) so you can pinpoint what AFR you want where...

Totally possible to get a really great tune with speed density.

One of the benefits is that it's based on what the engine actually needs, not an assumption (TPS) and it's much faster to change than TPS so when dialed in, the engine genarelly feels super snappy.