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Sensitive boost control

Boost Control

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I'm having a hard time getting just a few pounds of resolution out of my boost control solenoid. Very small changes in DC lead to almost 4 lbs of boost increase. I have twin 44mm gates and the vacuum line runs to a T between the two which are connected to the bottom port, the tops are both vented to atmosphere. I intend to get rid of the T and put another port into the bottom of one gate and daisy chain the vacuum lines to see if that softens the response. Someone else also mentioned a restrictor pill but I'm not familiar with an aftermarket solution for 4an lines. Any suggestions are appreciated.

What is a very small change? 1%, .1%, 0.01%


Have you tried different frequencies for your boost control solenoid?

If your top ports have AN-4 male fittings, you could get use AN caps, and drill a very small hole as a restrictor, then you could change caps with different size holes for testing.

Hey Dave. We've played with 31-33hz. About 4 lbs of boost from 1% difference in DC.

I would try down to 20 hz, and up to 40 hz, just to see if that helped.

What ECU are you using? Can you select values with a 0.1% or 0.01% change?

I know in MoTeC M1 Tune, we can change the number of decimals displayed for various tunable parameters and table values (Active Item->Properties) -- And the AEM Infinity can do the same (it's called Number Format Options in Infinity Tuner). Perhaps your software has a similar feature that would give you the resolution you want.

I'm on a Haltech Elite 1500. I'll have to look, I'm not sure.

It looks like the Elite 1500 has closed loop boost control. I assume what you are trying to do is get the Closed Loop Base Duty Cycle to hit the target before the Controller Start Delay allows the control to start.

The closed loop should be able to modify the duty cycle continuously to hit whatever target boost you want (as long as it's achievable). Perhaps the Controller Start Delay is too large, or in the Boost Control Setup the Control Point Offset is set to low, so increase the value so that Boost Control can help you hit the target.

The Closed Loop Base Duty Cycle table allows .1% values, so I would expect you should be able to get within .4 psi. The Closed Loop Control will either have finer resolution, or be able to change the duty cycle between the two values on either side of your target to hold it at the target.

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