I´ve searched and read a lot on the subject, but still can´t quite understand the differences between these 2 modes of operation. I´m installing a tactrix boost solenoid soon.

Could someone please help with this:
- Do you have to connect the hoses any different from what is shown in the attached diagram?
- Any tuning differences when doing the load or boost maps?


Thanks.

 

The diagram looks sensible for a 3 port (interrupt) solenoid.

3 port solenoids (interrupt) need less duty and correction than 2 port (bleed) (unless you had wild restrictors on the 2 port) because when the solenoid is energised there should be no pressure going from the compressor outlet to the actuator. So you need no restrictors and have a wider control bandwidth.

 

So, every 3 port solenoid works in interrupt mode when connected properly? Good to know thanks.

 

I just finished up testing a stock solenoid and several 3-port solenoids.

https://www.evolutionm.net/forums/sh...d.php?t=379043

The graphs give a feel for the difference in pressure at the WGA between a stock bleed solenoid and a 3-port solenoid.

 

Yes, it switches the wastegate actuator pressure source from compressor outlet to compressor inlet repeatedly with a square wave, the duty cycle setting the ratio between exclusively outlet (0%) and exclusively inlet (100%). In reality some ECUs, boost controllers or solenoids will not switch exclusively to inlet due to their pneumatic or electrical coil properties.

If you use 100% duty or exclusively inlet, then the turbo will build boost until the exhaust manifold pressure is sufficient to blow open the wastegate. This will likely bring the engine to full torque very quickly followed by full power which will hold in a straight line. You have a rally car style torque curve which makes for a very fast car - if you can control the direction of the car and your bottom end is not overwhelmed by the cylinder pressure from the massive torque.

Some great testing by mrfred there!

 

Great. Thanks guys.