All diodes have a reverse current behavior and most of the time we dont' want to witness it . it turns out, however, that if you apply voltage in the reverse direction and keep increasing the applied voltage, the diode junction will break down and the device will start to conduct reverse current. most signal and rectfier diodes you see will have a PIV spec -- peak inverse voltage. this is the reverse voltage that the junction can tolerate without breaking down.

Well, if you ignore that PIV spec, and continue to apply increasing reverse voltage, you find that the junction breaks down and begins to conduct current rapidly in the reverse direction. With the junction in this state, it acheives what is called "avelanche" which means that further increases in applied reverse voltage are not really possible -- the diode just conducts more current and the voltage drop across the device remains relatively constant.

This latter behavior is exploited in the zener diode. the junction is made so that it can tolerate reverse current, and the avelanche knee, as we say, is now the desired behavior. As you might expect, ordinary diodes make very poor zeners, and zeners make poor ordinary diodes.

So what you want to do is examine the behavior of several diodes -- look at their zener characteristics and find out how much current they need to pass in order to acheive the zener voltage.

attached is a circuit diagram, which should appear if/when the gods approve

 

Doug...****! Are you an EE?

 

Nice work Doug,

Im gonna have to drag out the multimeter and run up the engine a lil this weekend if it ever stops raining....uggg

Nice schematic too btw

 

doug,

Thanks for the great explanation and schematic. I have a question.
Does the computer keep ramping up the fuel till max boost is acheived? Or does it have a preprogrammed max fuel delivery that approximates max boost? In other words if we boost fool the system, and actually show a slightly low boost level, will the fuel ramp up to a higher level than stock. Approaching smoke levels or giving more than stock HP. I guess I'm trying to figure out how critical the avalanche voltage is and should we error on the low side. What will be the computers response to a low max boost?

Thanks again,

Wetspirit

 

hmmm. good question. but allow me to read between the lines, basically from what Dennis has said about the ramifier. Folks are telling us that their ramifiers are more aggressive in the low rpm range. We understand from Dennis's posts that the big difference between the Ramifier and other pressure boxes out there is the use of intelligent boost fooling. Dennis is saying to us that the three dimmentional map that includes boost is unique to ramifier -- so that tells me he's discovered that the ECM fools according to boost -- the ECM does not fuel to obtain boost.

Reading between the lines, that means the Ramifier can achieve higher fueling levels than other pressure boxes becuase it fools the ECM into thinking that boost is actually HIGHER than it really is.

This all my opinion of course. If this is true, think about what that means -- if the ECM fuels according to boost, then we definately do NOT want to give low boost values to the ECM. what we want to do with the boost fooler is cap it at the maximum level possible -- this will allow for maximum fueling. So no, do not err on the low side or your fueling will too. .

 

Doug,

Hmmm. Still thinking about that one, and confused.

Thanks for your thoughts,

John