MoTeC Global Forum

Hi Gents,

I'm experiencing an issue with a 2010 Subaru STI running an M800, where the overboost fuel cut limit isn't activating. Target MAP is 230kPa, and the MAP Fuel Cut Limit is set at 260kPa.
Boost has overboosted to 290kPa with no reaction from the ecu.

Could anyone provide problem solving recommendations..?

Thank you.
P

Are you sure it is set correctly ?

And there is a 1 second delay before it activates. Unfortunately this 1 second delay is not adjustable.

Whilst not a solution, you need to resolve your boost control so it doesnt overboost by such a margin.

I think its the 1sec delay that perhaps isn't activating boost cut...pity it cannot be altered.

I think I also discovered as to why overboost was being initiated.
Seems as if there was a Boost Comp table taking affect at partial throttle, lowering the boost target normal position.
Has anyone ever experienced a similar issue with a boost compensation of this nature..?

And I would like to get a better understanding of how the Overboost Axis actually works between the values 0 and 1...

Any assistance would be greatly appreciated.
Thank you.

Phoenix

Where are you getting 'OB'? Is there a user channel set up for 'OB', and what is it exactly? Overboost Limit Exceeded status flag? Take a look in user channels. Might be 'Overrun Boost' (antilag) or some other function. Look in the Error Flag and Status Flag list to see which it is.

Should be a direct interpolation between adjacent cells in the table when at a value between 0 and 1, however if 'OB' is a status flag that gets switched from 0 to 1 nearly instantaneously, the trim won't interpolate, it'll do what the cell says.

Whatever that is, when 'OB' is at state 0, its trimming 100% of the commanded BCS DC% when at 0% TPS. I suspect it is ORB Active not Overboost Cut. In which case it has nothing to do with an overboost situation.

Thanks for your input...
The mentioned table wasn't the cause of overboost, but rather a mechanical issue with the EWG.
I am however still struggling to control the boost efficiently.