Where should BOV get its signal from?

[YLD-16L]

Never used an external gate so I will await someone more knowledgeable to answer that.

Edit, looks like you'd still reference from the compressor or near it. See pic below:




It got me wondering if I was right after you mentioned it

[Dale]

OK, flame away
I actually have something a little different.

Believe it or not its actually a Toyota Lexcen

Now, the reason I asked is because I wasn't sure on how the BOV actually works. I knew it vented excess pressure from when the throttle butterfly closes between the supercharger and the butterfly ; but ; i thought it only did this thru a pressure signal (theres that signal word again) which in turn caused the BOV to expel the pressurised air. I was wrong. Its vaccuum in the plenum thru the closed butterfly which opens the BOV to expel the pressurised air.

Andrew ; thanks for your pic. Now for the 68 million dollar question.

With a wastegate ; where does the signal for that come from? Plenum or pre throttle body?

If it's a toyota why do I see the letters HOL and half of a D on the front grille

[Grega]

holiest of holies dale

[Andrew162]

Signals have been around since long before electricity was discovered. You have signal flares, signal flags (used in semaphore etc). A signal can be anything that indicates something, whether it be an electronic signal telling the ECU how far open your throttle is, or a vacuum signal telling your BOV to open. Could be a kettle wistling to signal that the water inside is boiling (for those who grew up with gas stoves)

yeah thanks for pointing that out dude, I could go into the fact that I was a 'Signalman' with the Army (not to be confused with signaller), which is someone that does communications and networks and shit, but that's just one other example in teh off-topic section.

[LeeRoy]

Wastegate signal: from the compressor housing or close to it.

This is where the positive pressure is and is the same as teeing it into the intercooler piping before the throttle (although you wouldnt). The actuator is pre set to open at a certain psi meaning you can buy 7psi actuators, 10psi, or whatever tickles your fancy.

Once positive pressure reaches the actuators set opening psi it will open and once it falls below this it will close. This happens continuously and it was regulates your boost levels. Keep in mind that whatever your wastegate actuator is set at is the lowest boost level the car will run but if you wanted to run more you could through the use of a boost controller.

Edit: just found this dodgy pic

[YLD-16L]

Edit: just found this dodgy pic

That's the same layout as the pic I posted except it is of a twin nippled actuator for an internal gate and that it says to reference form the intake manifold which would be not so good for a number of reasons:

Increased line length

Potential for pressure reference point to be lower than at the compressor housing (drop across cooler/pipework)

The introduction of vaccuum to boost rather than just atmospheric pressure to boost in controlling the diaphragm (yes it does make a difference).