dsp5 tables

[killerbee]

I'm NOT reading drive pressure. I'm using common sense. If the exact same vane position is creating the exact same boost at the exact same rpm, and the exact same fueling...

... then what do you suppose drive pressure is going to do?

[LarryJewell]

I'm NOT reading drive pressure. I'm using common sense. If the exact same vane position is creating the exact same boost at the exact same rpm, and the exact same fueling...

... then what do you suppose drive pressure is going to do?

seriously, before making comments about something you haven't tested, you really should test it. You really have no clue whats happening with drive pressure when you close the vanes , I thought you were testing things like heat and efficiency?

[killerbee]

Larry, do you think that any of the vane tables control vane position for boost control? They don't. Closed loop boost control, with the use of a boost controller, unexploded in EFILive, is used to vary vane position to meet DESIRED or COMMANDED boost.

IOW, boost is controlled with logic we have no access to, embedded in the ECM, part of the 1024 we don't see in tables. The vane tables mislead people into thinking they can be used to influence boost, when in reality, the only useful table is max vane, and that only permits the production of higher boost numbers, albeit at considerable cost to drive pressure, naturally. But if we are talking about relatively low boost numbers, like 20 psi stock tuning, then raising max vane has no effect.

Target vane, just gives a vane position "rest" place when there is no disparity between set point (desired) boost and present boost. It is, more or less, a worthless table to the tuner. IMO

[jpgmtech]

Target vane postition is accessed on a delta TP event to provide an initial reference for the vanes. After a certain predefined delay to allow the turbo to respond, the ECM starts modulating the vanes to produce the boost requested in the Desired Boost tables.

Changing turbo vane target primarily changes the responsiveness of the turbo. It has no effect on final vane position once fuel rate is stable.

In my experience, the stock max vane tables will allow as much or more boost than I am comfortable with the stock turbo. Just set the desired boost table to the maximum value, and the ECM will always run the vanes up to the maximum limit.

This is not what KB did: he set Desired Boost to 20psi and ran the max table at 100%... even though the max table was set high, the ECM will only modulate the vanes to get 20psi, usually 30-40% at a lower altitude. The ECM has no reason to go for higher vane position, therefore drive pressure remains stable.