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- Before attempting to tune the boost control system it's important to make sure that the inputs and outputs to the ECU are configured and operating correctly.
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00:10 |
For a boost control system, this should be fairly straight forward since the main input of manifold pressure is usually shared with the load input to the ECU and hence should already be configured correctly.
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00:24 |
The boost control solenoid will need to be wired though and it's important to test this and ensure it's functioning as you'd expect.
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00:32 |
The configuration options will depend, to an extent, on the ECU you are tuning, and we'll look at the specifics of this more as we move into the worked examples section.
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00:42 |
However, in general, you'll need to define an output to operate the solenoid.
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00:48 |
A boost control solenoid is a simple magnetic coil and it isn't polarity conscious.
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00:53 |
Which means, it doesn't matter how you connect it to the ECU.
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00:58 |
The boost control solenoid requires a 12-volt power source to one side of the coil winding and a ground to the other in order to energise the solenoid.
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01:08 |
Conventionally, most ECUs will provide a switch ground to the solenoid which requires the other side to be connected to a 12-volt source that is live when the ECUs powered up.
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01:20 |
This is similar to how a fuel injector would be connected and controlled.
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01:25 |
Some ECUs can, however, be configured to provide either a ground or a 12-volt to the solenoid, and in this case, you'll need to configure the ECU to suit how the solenoid's being wired.
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01:39 |
Once the solenoid is wired, you can see the frequency that it will operate at.
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01:45 |
As we saw in the boost control solenoid operation module, we need to choose a frequency to suit the solenoid.
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01:53 |
The useful range of operating frequency, is around 15 to 20 hertz for the popular solenoids that are commonly used for boost control, so 15 hertz is a safe place to start.
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Once you've set the frequency, you can perform an output test to ensure the solenoid's functioning.
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02:10 |
You should be able to hear it audibly clicking when it's operating.
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02:14 |
It's always easiest to test the solenoid at this point to avoid chasing wiring problems once you get to the dyno, and find the boost control isn't working.
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02:24 |
One other aspect that's really critical to configure is the polarity of the solenoid.
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02:29 |
This isn't an option on all ECUs but if it is, it defines whether a duty cycle of 100% of the boost control tables will command the solenoid to be fully open or fully closed.
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02:42 |
Getting this wrong, can mean your boost control system works in reverse, and this can result in huge overboost problems, which could potentially damage your engine.
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02:53 |
Since I've just mentioned overboosting, this is the perfect time to set up an overboost cut out to protect the engine.
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03:00 |
Always do this during the configuration process, so that there's a safeguard present in case I end up with two much boost for any reason.
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03:08 |
It's easy to adjust the boost cut out at a later point, but for now I'd suggest setting the boost cut two to three psi higher than the minimum boost you're expecting to see.
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03:20 |
With the solenoid set up and tested, our configuration is basically complete.
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03:25 |
The only other aspect we may need to consider is a switch or rotary dial to allow multiple boosts settings to be configured in the ECU.
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03:34 |
In this case, we may want to configure a digital input as a high-low boost switch or an analogue voltage input to provide multiple boost targets.
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03:45 |
We'll look at setting these inputs up in the worked examples.
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03:50 |
With the configuration out of the way, we can now look at how to tune the boost control system, and we'll cover that in the next two modules.
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