Diode for boost control solenoid?

[Jon K]

Hey guys - anyone running a diode across the wires for their boost control solenoid? I don't see it mentioned in the DTA wiring diagrams but just curious as many articles on using these MAC solenoids mention some guys doing it.

Thanks,
Jon

[stevieturbo]

I'm using a 4 port MAC on mine, no diode, no problem.

What is the diode supposed to do ?

[Jon K]

I'm using a 4 port MAC on mine, no diode, no problem.

What is the diode supposed to do ?

Awesome Steve. Can you describe/draw/picture how your 4 port is hooked up? Trying to figure out the best way. I am running one turbo but two wastegates.

Any inductive load (electric fan, ign coil, relays, solenoids) have the tendency to store up a charge. When the ECU let's go of their ground, that current can fly back into the ECU. By putting a diode between the +12v and GND nearest the solenoid/etc, you're essentially making a small loop circuit that lets the current/voltage dump into a loop that excludes the ECU. Its for protection. DTA may have something inside, I am not sure.

[stevieturbo]

I'm using it so I can blow my BOV open to vent boost in the lower gears to try and reduce power, for more chance of traction.
But then off boost it operates as the BOV would normally do.

The valve is simple.

http://www.ebay.com/itm/Boost-Solenoid- ... ts&vxp=mtr


Basically at 0% duty it you hook it to the bottom port of your w/g to blow it open as normal. The other port is open to atmosphere via the solenoid.

Then as this increase to 100% duty, you will be blowing all pressure into the top port, with the bottom them vented to atmosphere. So this will give you a very high max boost setting

0-100 is anywhere in between. Obviously you can flip that about so 100% would be min boost and 0% max boost.

So it should give a much wider range of control over the wastegate.

[Jon K]

Interesting Stevie thanks for that

How many wires is it? How did you wire it?

[Wally]

I'm using a 4 port MAC on mine, no diode, no problem.

What is the diode supposed to do ?

As you are interested in scopes, have a look at this about a 30 amp relay switching

http://www.picoauto.com/video/automotive-relay.html

Wally

[Jon K]

Thanks wally - that shows exactly what happens (or can)

That said - do we need a diode across the boost control solenoid?

[stevieturbo]

Interesting Stevie thanks for that

How many wires is it? How did you wire it?

it's just 2 wire, same as a normal solenoid.

[stevieturbo]

I'm using a 4 port MAC on mine, no diode, no problem.

What is the diode supposed to do ?

As you are interested in scopes, have a look at this about a 30 amp relay switching

http://www.picoauto.com/video/automotive-relay.html

Wally

Wow, would never have expected that.

[Jon K]

I'm using a 4 port MAC on mine, no diode, no problem.

What is the diode supposed to do ?

As you are interested in scopes, have a look at this about a 30 amp relay switching

http://www.picoauto.com/video/automotive-relay.html

Wally

Wow, would never have expected that.

Yeah man - and, it can cause relays to not shut off. Can get scary on nitrous setups - this was part of my concern and why i am interested in running Solid State Relays for nitrous.