Been having a discussion with Ryan about this!!

Now Ryan tells me that they are basically a variable resistor connected somewhere into the map sensor circuit....


Now, HOW exactly does this affect boost?? As the way I see it, placing a resistor in the circuit will make the ecu THINK that there is less boost than there actually is!!

Now then, obviously the car is mapped fuel wise, MAP versus RPM. BUT now with the boost pot on, the ecu is 'seeing' LESS boost than there ACTUALLY is, and therefore provide the correct amount of fuel for the boost it's 'seeing' for a given rpm. When really, it's getting MORE boost than that!!

Obviously, this will make the engine run lean and melt


I know these things obviously work and the above can't be true??


I just can't see the relationship between fiddling the the map sensor signal and boost control, as obviously the amal valve or air injectors come into play somewhere in the equation.


Anybody know exactly how these things do it please??

Thank you in advance

 

goes to a seperate pin on the ECU Pin 9 so has to have hardware changed aswell.

no just a plug and play job.

im not 100% if it alters the map signal or simply the signal to pin 9.

I havent looked into it that much, just make the things. dont car how they work

so it might just be a 0-5v signal to pin 9, and the potentiometer adjusts the voltage accordingly, and then the ecu map is altered accordingly.

 

its a pot with a voltage sweep between 0-5volts

different boost maps are enabled according to the voltage on pin 9

 

Does it adjust ONLY the boost maps, or do whole map switching ( with the boost map adjusted)??

 

only the boost maps

 

here it shows (in descpro) how the voltage relates to boost position knob

 

And you can alter that to reflect 12 positions on the knob?

Cool, cheers Gareth!!

 

yes mate,,,, i only have a 4 position knob in my car

 

think t6 cant do 12 position from what harvey said, only 4 like you've got Gareth, least i seem to remember him saying that.

 

i think your right dude,,, ill have a play now

 

To be fair, you probably dont need 12 really - it'd just be a 'volume' knob!!