Custom Supercharger and FVD tuning
09-21-2007, 03:27 PM
#31
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09-21-2007, 04:32 PM
#32
Race Car
The maf works like this. There is a thermistor as a sensor, it is used to be heated, at a set (constant) temp. As air flows by it, it will cool... the computer tries to heat it up more since it wants it at constant temp. The voltage that is required to heat up the thermistor is proportional to the amout of air that tries to cool it. The varying heating up and cooling down is the signal of the airflow.
09-21-2007, 04:36 PM
#33
Race Car
See, this is different technology than how the American cars do it once you have exceeded the capability of the MAF. You simply got a bgger CFM one that matched the injector size.
Good stuff.
09-21-2007, 04:46 PM
#34
Burning Brakes
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09-21-2007, 08:55 PM
#35
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Numbers
Curious which establishes the MAF ERROR is it the ECU or the MAF? Is it voltage, amperage or resistance it looks at? If the MAF/ECU has a operating range of 5V and the engine at idle with regular CFM flow *no boost" why are the data numbers showing rpm between 500-3000 and being within that range?
09-21-2007, 09:17 PM
#36
the maf range is 0-5v, at 2.5K rpm you are already past mid scale of the maf. This is what 1999 is saying. it looks like you need to lower that signal so it will match 0-redline rpm = 0-5v.
I have to open up my air intake and see if evo have baffled the maf somehow so it will see lesser air flow, maybe this is how they done it instead of the resistor.
I have to open up my air intake and see if evo have baffled the maf somehow so it will see lesser air flow, maybe this is how they done it instead of the resistor.
09-21-2007, 09:47 PM
#37
Race Car
Curious which establishes the MAF ERROR is it the ECU or the MAF? Is it voltage, amperage or resistance it looks at? If the MAF/ECU has a operating range of 5V and the engine at idle with regular CFM flow *no boost" why are the data numbers showing rpm between 500-3000 and being within that range?
'99 and redridge probably will throw in more theories but I think it is time to haul the enigne to a dyno and have GIAC professionally tune. There isnt any tuners on this board, or at least I have never heard anyone talking on that level. If there is, they should of stepped up by now.
Everytime this is discussed, I think of this time about 12 years ago when this professional drag racer (leaving his name out) here thought he could lean the motor to get more power. He just learned DFI (Digital Fuel Injection) and typed in a few keystrokes on the keyboard and on his next pass, bam!!!! 1800hp motor blown into bits. Hope this doesnt happen to you.
09-21-2007, 10:55 PM
#38
Burning Brakes
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maf
the maf range is 0-5v, at 2.5K rpm you are already past mid scale of the maf. This is what 1999 is saying. it looks like you need to lower that signal so it will match 0-redline rpm = 0-5v.
I have to open up my air intake and see if evo have baffled the maf somehow so it will see lesser air flow, maybe this is how they done it instead of the resistor.
I have to open up my air intake and see if evo have baffled the maf somehow so it will see lesser air flow, maybe this is how they done it instead of the resistor.
Last edited by Mother; 09-21-2007 at 11:18 PM.
09-21-2007, 11:10 PM
#39
Burning Brakes
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Tippy, Having this thread and input from you and others helps the person making these mods in the future. I agree I have blown my fare share of engines in the past and am trying to approch this with some caution. FVD is doing my tuning as we speak there german engineers will be back Monday and we will go from there slowly as they put it. What's nice is they take your suggestions and listen and I like that, rather then we know it all.
The first step is get it to idle at my house so I can leak check etc etc... Then when ready take it to a dyno for the fine tuning it is costly for dyno runs $100 an hour or so.
The first step is get it to idle at my house so I can leak check etc etc... Then when ready take it to a dyno for the fine tuning it is costly for dyno runs $100 an hour or so.
09-23-2007, 09:11 AM
#42
Race Car
Curious which establishes the MAF ERROR is it the ECU or the MAF? Is it voltage, amperage or resistance it looks at? If the MAF/ECU has a operating range of 5V and the engine at idle with regular CFM flow *no boost" why are the data numbers showing rpm between 500-3000 and being within that range?
Don't forget that airlfow is dependant on throttle position. You can a have high MAF signal at low rpm as well as a low signal at high rpm depending on what you throttle is doing.
Last edited by 1999Porsche911; 09-23-2007 at 09:43 AM.
09-23-2007, 10:36 AM
#43
I really don't believe that burning out the MAF is a concern. Maxing out the voltage (due to high airflow) is a concern but not because of buring the wire out. The concern is that you are the uppper end of a sensors range (and possibly beyond it). This means that you're supplying more air than the ECU knows how to compensate for and you will either throw a code or start running lean. The current through the MAF wire is limited by it's intrinsic resitance and the maximum 5V that will be supplied to it. Granted, if you let it sit a max voltage and therefor max current it will have a shorter life (as 1999 pointed out), but this is a secondary problem in comparison to the potential for running lean and destroying your engine. 1999's suggestion of placing a resistor in the circuit will lower the current should work to prevent that problem but I just don't think it's that big of an issue. My additional concern with this method is that you're changing the output from the MAF which would then have to be adjusted for in the EFI tuning. If you're maxing out the maf sensor I'd change sensors.
09-23-2007, 12:47 PM
#44
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Throttle
According to the readings I am not maxing out the voltage but they seem erroneous with low throtttle applied. I suppose that if the ECU is calibrated to receive so much fuel at a given votage and throttle angle then it should run either rich or lean depending, but it does neither it hunts.