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DELETED (Inactive)
4 Posts |
 Posted - Aug 24 2003 : 11:32:20 PM
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hey fokes... I'm trying to save myself $700 (stuff buying an Apexi safc) by building a small device that will regulate a voltage 5 to 20% lower than the supply or referece... this is for a map (mass air preasure) sensor in a car.. by showing the car's ecu that there is a lower voltage coming from that sensor it will allow me to run more boost and also lean off toyota's extra rich fuel maps.
in the past I have used zenor diode to cap the sensor voltage just before boost cut, but now I want to make it show lower voltage all over the boost range and this will also in turn keep the factory boost cut in place for a fail safe (if my wastegate fails)
I was thinking about a regulator of some sort, but I don't know enough about them...
the voltages I'm working with are a 5v supply (regulated by the ecu to the sensor) and it's return voltage that goes to the ecu. so I'm working from like .5v to 5v.
if anyone could help me it would be fantasic!..
thanks, matt
-matt
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Aug 26 2003 : 11:00:20 AM
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Buy the S-AFC. You can find them cheaply on eBay. I have a friend who was building a similar device from scratch for his University project. It's a lot more complicated then it sounds.
The S-AFC does so much more then just bring down the air-flow meter signal.
I can't see how showing a lower AFM signal will effect your boost in any way. Boost is regulated via the wastegate, which has nothing to do with the AFM. What car is this? Is there a "stock" boost controller setup? Most older cars use a strictly mechanical system, while newer cars have a boost duty solenoid to regulat the wastegate.
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DELETED (Inactive)
4 Posts |
Posted - Aug 30 2003 : 01:43:24 AM
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quote:
The S-AFC does so much more then just bring down the air-flow meter signal.
I can't see how showing a lower AFM signal will effect your boost in any way. Boost is regulated via the wastegate, which has nothing to do with the AFM. What car is this? Is there a "stock" boost controller setup? Most older cars use a strictly mechanical system, while newer cars have a boost duty solenoid to regulat the wastegate.
no I wasn't saying that the afm signal deturmines the amount of boost the turbo runs or that the afm controls the wastegate... I am saying that the fuel cut on cars ecu's is from the amount of pressure in the inlet manifold... this is becuase the ecu doesn't want you to lean out and detonate, or blow a HG from the pressure...
Now AFM cars use a simple calculation of air flow volumetric efficency and RPM to deturmine around about how much pressure is there...
now having said that... the car this is for is map senserd... no dodgy afm here...
a SAFC doesn't do alot... I gives you fancy pants reading of stuff like rpm, boost and crap in a nice blue vacumme display... I'm not interested...
all It DOES to the car is at set rpm points (I think 500 RPM res. you can change the sensor trim. that's it..
but I don't need that.. I just want an overall 5 - 20% lower figure
-matt
+61 404292016 |
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DELETED (Inactive)
4 Posts |
Posted - Aug 30 2003 : 01:45:48 AM
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oh... by the way aaron... Thanks for your time to reply :) much appreciated!!!
-matt
+61 404292016 |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Sep 02 2003 : 10:21:20 AM
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If all you want to do is lower the voltage from a specific sensor (ie boost/pressure sensor), then all you need is a voltage divider. But this is a very crude way of doing it.
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DELETED (Inactive)
4 Posts |
Posted - Sep 03 2003 : 8:08:55 PM
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crude it is... yes it works....
I have already designed and tested it now...
works fine indeed.....
Thanks for your help aaron.
-matt
+61 404292016 |
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regulating a voltage 5- 20% lower than supply
