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In some post you mentioned that you have information about the Renault Renix ECU. If it isnt too much trouble, could you please mail me it? As Ive been looking for info from everywhere, but have found nothing useable really...
Ok, I thought that if you had some files about it in computer which would be easy to send, but if it is on paper or in your head its bit more difficult
I would like to know about its working principle and about that diagnostics socket. Fastchip (www.fastchip.nl) sell this info display which connects to diagnostics socket, and with that you can see all the variables which are used by ECU.
So I thought if I could make similar device myself. But then I should know more about the socket and which pin gives which information.
With some microprocessor it shouldnt be too difficult.
on a turbo car ie A3 t... then it is simply a change to the boost level and boost level cut off..
allowing a small increase in rpm can allow the boost to spiral up too. so 30 bhp is simple.. (but, the owner could do it himslef in a cruder way for 2 quid !!!! (with a brass tee piece, plumbers solder and a fine set of drills )
superchips can alter a limited amount of positions in the ecu fueling map and ignition map. These can overide the manufacturers data and richen up the mixture mid range and top given a small increase in power but hardly, if at all, noticable.
Manufacturers lean out the mixture on cruise and part throttle for both economy and emissions.. so you will lose economy slightly and emissions may increase.. all in all not really worth it on a N/a car.
controlling the boost on a mechanical actualtor by electronic means is actually quite simple.
heres how it works.
if you can imagine a simple pipe from the compressor outlet (Boosted air pressure) connected to the wastegate valve.. then at a given pressure the wastegate will open allowing exhaust to bypass the turbo drive impeller. yep ?
this will hold a specific pressure and reach it as quickly as possible.
now.. if we introduce an electronically controled valve IN that pipe.. we can close the valve to stop the wastegate actualting - ie - it doesnt see the pressure..
to make it all work properly.. heres what we do.
the valve to use is a PWM solenoid.. PWM = pulse width modulated - basically you can turn it on and off rapidly and also control the mark to space ration - ie the period ON TIME to the period OFF TIME.. this allows you to control how much pressure the waste gate sees at any given time by varying the flow of compressed (boosted) air to the wastegate..
now what ya need to do is change the wastegate assembly or alter the spring internally so that the wastegate is operating at a lower pressure - ie - comes in earlier.. you now use the valve and pwm circuit to raise the actuation pressure to the desired level.. now you have control over the ramp up time - ie, you are not waiting for the preset 6-10 psi to come in. and the abrupt delivery of power, you can effectively cut boost at, say 3 psi, then allow it to build up in a controlled manner in any way you require.
Hope that helps.. the best ideas are the simplest LOL..
well, yes, sort of.. the mechanical part is still there... just that you can trick the wastegate into seeing different pressures (always below - never above waht is available)
the lowering of the actuation pressure of the wastegate is the trick most often bypassed or missed by turbo add on manufacturers (as well as air temp control !)
By lowering the actuation pressure of the wastegate you have contrl over the ramp up time as said above.. this allows you to bring the turbo in progressively, and also then to allow any boost level you require.. up to TNB