VersaTune User Forum

Dolfius wrote: ↑July 15th, 2020, 6:07 am Flow = load, actually. 21 psi on a k04 and 21 psi on a bigger turbo will not yield the same load. I understand the principle.

Boost is a measure of how much air from the intake manifold is making it into the engine.
21 PSI on a K02, K03, GTX4088, through the same intake manifold, same BAT, at the same RPM and intake valve advance, and the same barometric pressure is actually exactly the same flow in grams per second or lb/min or whatever. Same amount of air.

Dolfius wrote: ↑July 15th, 2020, 6:07 am I'm referring to the MAP Targets (Boost Targeting Mode) table specifically. What does that do? How does that come into play?

That comes into play every time you have a properly configured comp boost vector and the other limits (load, whatever) are not hit yet.

mituc wrote: ↑July 15th, 2020, 7:55 am Boost is a measure of how much air from the intake manifold is making it into the engine.
21 PSI on a K02, K03, GTX4088, through the same intake manifold, same BAT, at the same RPM and intake valve advance, and the same barometric pressure is actually exactly the same flow in grams per second or lb/min or whatever. Same amount of air.

My point being, the g/s = load. Calculated load on our ECUs=((g/s*60)÷RPM)*2/3)

mituc wrote: ↑July 15th, 2020, 7:55 am That comes into play every time you have a properly configured comp boost vector and the other limits (load, whatever) are not hit yet.

So for example, if load targets aren't reached yet (nor any air temps or baro pressure limits), the ECU will use this table to reduce the boost anyways? By gradually closing the throttle plate? Or reducing wastegate?

Dolfius wrote: ↑July 15th, 2020, 8:35 am So for example, if load targets aren't reached yet (nor any air temps or baro pressure limits), the ECU will use this table to reduce the boost anyways? By gradually closing the throttle plate? Or reducing wastegate?

Yes, by reducing the wastegate IF the boost comp vector is populated properly.
The throttle reduction will happen when the boost protection limit throttle reduction values are reached. If the tune is consistent then these limits should be lower than the boost targets.

Correct me if I am wrong (but I am pretty sure about this):
Originally (stock tune) the Mazdaspeeds are load AND boost tuned (kind of hybrid or mixed tune where both, load and boost "error" (better: deviation) corrections will happen, i.e. there's some target load (the well known set of TL tables) and target boost (-> table "MAP Targets") which trigger the ecu operations for wg and tp adjustments in order to reach some calculated target state.
In contrast to ATR, where even pure boost tuning is possible, VersaTuner only allows for pure load tuning so these boost error correction tables are simply ignored - apart from the "boost limit exceeded" correction table which comes into play as soon as the specified boost limit throttle close values are reached/surpassed.
Since there's no "boost targeting mode" in VT (at least it cannot be activated up to now), you can put in the boost target correction table whatever values you want - they won't have any effect!