maf mod
11-23-10, 05:33 PM
#27
The S5 still has an AFM. It's different from the S4 version, but it's not an actual MAF. Still called the same thing in the FSM.
There's more to it than this really. The stock fuel delivery map is RPM vs. MAP pressure, and the AFM, AIT sensor, ATP sensor, water temp sensor values are used on top of that for fuel corrections.
The stock timing map is RPM vs. LOAD, where LOAD is apparently calculated somehow from AFM, MAP and other sensor data. It's complicated, but it's also very dynamic in the way it allows the ECU to compensate for simple intake/exhaust modifications as well as boost pressure increases.
the "pressure sensor" (MAP sensor in reality) is used to adjust the timing according to engine load. FCs also have a barometric pressure sensor located behind the passenger side right kick panel for altitude fuel adjustments. it is now, looking back, an overly complicated system with too many points for failure.
The stock timing map is RPM vs. LOAD, where LOAD is apparently calculated somehow from AFM, MAP and other sensor data. It's complicated, but it's also very dynamic in the way it allows the ECU to compensate for simple intake/exhaust modifications as well as boost pressure increases.
11-24-10, 12:00 AM
#30
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newer cars usually take a baro reading when the key turns on, but before the engine starts.
11-24-10, 12:00 PM
#32
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so i went to to oreillys the auto part store and had my buddy look up the serial number for the maf an it turns out the it the same maf that the s4 use so that y i didnt see a difference. so the maf for the supra mk3 is the same as for the fc s4. you guys can double check if you dont trust my info no hard feelings if you do lol
11-25-10, 11:35 AM
#36
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so i went to to oreillys the auto part store and had my buddy look up the serial number for the maf an it turns out the it the same maf that the s4 use so that y i didnt see a difference. so the maf for the supra mk3 is the same as for the fc s4. you guys can double check if you dont trust my info no hard feelings if you do lol
are you sure its from a mk3 supra not a mk2 supra?
mk2 look similar to S4's but mk3 are straight through (no flapper or door)
my 7MGTE or mk3 supra AFM looks like this
11-25-10, 12:28 PM
#37
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here are a couple of hints.
1. mark where stock is first. a little paint mark somewhere on the spring wheel and the case are perfect.
2. put a voltmeter on the ecu pins. i found my gsl-se afm was 100% open @4500rpms. once the AFM is 100% open, which is think is 0v on an FC, you cannot go any richer.
3. the FC afm has a stopper for the closed position, the older ones have a stopper for the open position too, depending on how/what you're trying to get out of the ECU i think it would be a legal mod to add one.
4. the miata guys actually take the AFM resistors out and wire em to individual pots, which is EXACTLY the same as the ANCIENT 5 **** SAFC. so the newer SAFC's are better
Not true
11-25-10, 06:58 PM
#41
It has to have an RPM, TPS, and AFM input to work. It can't just generate one based on RPM and throttle position.
It sucks as a tuning tool too. At least for s4's, having the TPS that only reads the first 25% of throttle position.
11-27-10, 05:07 PM
#43
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i got it from an mk3 but they might have change the model in the later models i will post some pics tomorow and get you guys the model number
11-28-10, 11:36 AM
#44
when you stab the throttle at low RPMs the MAP reads 5 volts or 0" of vacuum regardless of engine RPMs, the AFM is still only part way open because it is still increasing its opening as RPMs rise. so taking the MAP signal alone and turning it into an AFM signal is impossible without having a more complex way of integrating the engine RPMs into it, which to my knowledge the SAFC still can't do, it can however invert the signal depending on how you have it setup. it's basic function is to simply take the AFM input signal and modify it 50% up or down to trick the ECU into thinking there is more or less air passing the AFM than is actually going through.
tricking the ECU AFM reading has the adverse affect of not adjusting the timing properly, as i earlier mentioned that the MAP sensor is the input for timing it isn't the only one, it is just the MAIN one for adjusting the timing. if the engine thinks it is under more of a load than it really is then the timing is retarded more as a result, when you install larger injectors and lean out the AFM signal you get the reverse which is increased timing over stock. adjusting static timing is something that should be common practice in conjunction with piggybacks like this, unfortunately most people don't realize what is going on and are hurting performance or push things too far to the point of turning the engine into a brick.
11-28-10, 06:09 PM
#45
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or maybe a MAF input and AFM output.
in reality you're right the MAP signal is 0-5v, while the AFM is 5-0v, so they are just reversed.
although karack has a point too, just inverting the voltage signal might not drive well...
11-28-10, 06:35 PM
#46
even so, the AFM measures airflow and the safc can't amulate a combined MAP sensor signal and RPM signal into an AFM signal.
when you stab the throttle at low RPMs the MAP reads 5 volts or 0" of vacuum regardless of engine RPMs, the AFM is still only part way open because it is still increasing its opening as RPMs rise. so taking the MAP signal alone and turning it into an AFM signal is impossible without having a more complex way of integrating the engine RPMs into it, which to my knowledge the SAFC still can't do, it can however invert the signal depending on how you have it setup. it's basic function is to simply take the AFM input signal and modify it 50% up or down to trick the ECU into thinking there is more or less air passing the AFM than is actually going through.
tricking the ECU AFM reading has the adverse affect of not adjusting the timing properly, as i earlier mentioned that the MAP sensor is the input for timing it isn't the only one, it is just the MAIN one for adjusting the timing. if the engine thinks it is under more of a load than it really is then the timing is retarded more as a result, when you install larger injectors and lean out the AFM signal you get the reverse which is increased timing over stock. adjusting static timing is something that should be common practice in conjunction with piggybacks like this, unfortunately most people don't realize what is going on and are hurting performance or push things too far to the point of turning the engine into a brick.
when you stab the throttle at low RPMs the MAP reads 5 volts or 0" of vacuum regardless of engine RPMs, the AFM is still only part way open because it is still increasing its opening as RPMs rise. so taking the MAP signal alone and turning it into an AFM signal is impossible without having a more complex way of integrating the engine RPMs into it, which to my knowledge the SAFC still can't do, it can however invert the signal depending on how you have it setup. it's basic function is to simply take the AFM input signal and modify it 50% up or down to trick the ECU into thinking there is more or less air passing the AFM than is actually going through.
tricking the ECU AFM reading has the adverse affect of not adjusting the timing properly, as i earlier mentioned that the MAP sensor is the input for timing it isn't the only one, it is just the MAIN one for adjusting the timing. if the engine thinks it is under more of a load than it really is then the timing is retarded more as a result, when you install larger injectors and lean out the AFM signal you get the reverse which is increased timing over stock. adjusting static timing is something that should be common practice in conjunction with piggybacks like this, unfortunately most people don't realize what is going on and are hurting performance or push things too far to the point of turning the engine into a brick.
youve got a point with timing, but you may be able to just retard the CAS. wouldnt be very exact tune, but maybe work for someone on a budget
11-29-10, 03:42 PM
#50
http://www.oreillyauto.com/site/c/de...or%21s%21meter
Check the compatability tab.
I searched on Oreilly's website, they say the part's interchangeable. Now, I'm not saying that a discount auto parts store's parts list is a good source, but it's quite possible since alot of manufacturers use parts from a common source.
Check the compatability tab.
I searched on Oreilly's website, they say the part's interchangeable. Now, I'm not saying that a discount auto parts store's parts list is a good source, but it's quite possible since alot of manufacturers use parts from a common source.