MoTeC Global Forum

Could I ask: what is the exact calculation for Boost Trim, given

Simple Boost Control;
Inverted Polarity;
Negative Trim i.e. -40;
Starting Frequency Valve Boost Values of 15,15,15,...,76,76,76,76,76 i.e. Valve fully on whilst boost builds, then set to hold at 76 which (remember my Polarity is inverted).

uvii wrote:Could I ask: what is the exact calculation for Boost Trim, given

Simple Boost Control;
Inverted Polarity;
Negative Trim i.e. -40;
Starting Frequency Valve Boost Values of 15,15,15,...,76,76,76,76,76 i.e. Valve fully on whilst boost builds, then set to hold at 76 which (remember my Polarity is inverted).

It really depends how do you set up your boost control in the first place.

Let's say per your example, that you only have set up the Open Loop boost control:

The result it will be 12.75, 12.75...64.6, 64.6...

It will only matter the solenoid polarity, if your numbers were getting smaller while the boost is getting higher.
This set up is just to make things more logical on the tables.

If you'd have Closed Loop control, the TRIM would make the same percentage changes, however to the AIM Boost it self.

Ex Was: 200 KPA Target
Ex It will be: 170 KPA new Target.

Sorry, Im still not sure how 15 becomes 12.75 and 76 becomes 64.6 with a Trim of -40 with Open Loop control. What is the maths that determines the translation?

The Trim MoTeC pages says it is a percentage Trim, so I would expect 15 to become 9 and 76 to becomes 45.6 i.e.
a Trim of negative 40%. If the Trim was positive I would expect to add 40% of the base value.

And yes if I have high frequency valve values my boost gets lower - it's just how it was set-up.

uvii wrote:Sorry, Im still not sure how 15 becomes 12.75 and 76 becomes 64.6 with a Trim of -40 with Open Loop control. What is the maths that determines the translation?

The Trim MoTeC pages says it is a percentage Trim, so I would expect 15 to become 9 and 76 to becomes 45.6 i.e.
a Trim of negative 40%. If the Trim was positive I would expect to add 40% of the base value.

And yes if I have high frequency valve values my boost gets lower - it's just how it was set-up.

Sorry uvii you are right. I was doing the math based on what I have on my boost Trimm (-15%). That's why I end up with that number.

As you can see I made the same mistake for close loop control.

Regards

Felipe