|
|
Joined: Nov 2000
Posts: 10,015
Hard-core CEG'er
|
Hard-core CEG'er
Joined: Nov 2000
Posts: 10,015 |
This MAFia thingamajingie sounds like a POS. Also the claim that lightning and cobra mafs are expensive and inaccurate is utter garbage. What's inaccurate it the BS scaling this snake-oil bit of electronics does. Get a clue - ghetto mods don't work properly. 
2000 SVT Turbo 295hp/269ftlb@12psi
#1 for Bendix Brakes Kits!
Knuckles rebuilt w/new bearings $55
AUSSIE ENDLINKS $70
Gutted pre-cats $80/set
A lack of planning on your part does not constitute an emergency on mine!
|
|
|
|
|
Joined: Aug 2001
Posts: 5,810
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Aug 2001
Posts: 5,810 |
Originally posted by ButtonPuncher:
Originally posted by warmonger:
So I'm guessing you have to use one of their special MAFs in order to get the 7 volt output scale, then you are rescaling it with electronics to fit back into the factory 0-5v scale?
Nope, no special MAF required. The stock MAF can put out over 5 volts. It's just that the PCM can't understand anything over 5 volts. The MAFia or Mafextender just scales the voltage down to the 0-5 volt range that the PCM can understand.
$150 for something that can make your stock MAF the size that you need and not waste resolution. Sounds pretty good to me.
BP
Not me. Sounds like a waste of money.
Especially when you understand that the "MAF" doesn't "put out" any voltage of its own. It has a source/reference voltage that comes from the PCM and it 'does something' from this voltage. Think of the pcm maf wires as ~5v battery, +/- 1 volt and the MAF as a circuit that uses that voltage and returns some portion of that voltage. 7 volts seems out of the range to me.
If the Mafia does something to amplify the signal and then rescale it then perhaps.
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
See My Mods
'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
'06 Mazda5 Touring, 5spd,MTX, Black
|
|
|
|
|
Joined: Aug 2002
Posts: 1,224
Hard-core CEG\'er
|
|
OP
Hard-core CEG\'er
Joined: Aug 2002
Posts: 1,224 |
OK guys hear me out...
The stock MAF puts out more than 5 volts when driven over it's stock flow. 7 volts definitely isn't out of range. Heck, if you regulated it, there's no reason that you couldn't push 9 volts. It is fed battery voltage. Don't believe me? My Fluke doesn't lie...
I'm saying that the Lightning/Cobra/Mustang MAF can be less accurate because you can't size it to your application. It is fixed. With the MAFia you can effectively vary the size of your MAF to fit your power level. That way you aren't wasting any resolution.
The stock Zetec MAF is just under 2.5" I.D.. Theoretically it should flow way more air than I will ever need. (And more power than most of you guys will need.) To quote...
Originally posted by DrFrankenbarge:
So if we go to the limit with 450 hp worth of air you're looking at around a 2.25" OD tube at 450 f/s (Mach .4). So to give yourself a little breathing room 2.5 should easily flow fine for 450hp.
Now say we are using this kit on a decent 2.5L and say we're making about 275 at the crank. For a velocity of 450 f/s you're looking at about a 1.75" OD tube (say 16 gauge wall).
This isn't snakeoil guys. It's a valid product. There isn't any voodoo going on. All that it is doing is scaling a voltage down. Pretty simple and very effective.
BP
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list. 
|
|
|
|
|
Joined: Aug 2002
Posts: 3,732
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Aug 2002
Posts: 3,732 |
better off doing it right. a mustang gt maf would probably be great for your application. and with the PRP it can be tuned easily with no "scaling" imo the MAFia is a ricer mod. i myself will be using a lightning maf with the turbo 
Russell
Oval Port 3L Nearly Done
MTX75 w/ Homebrew Zetec FD and Torsen Complete
|
|
|
|
|
Joined: Mar 2001
Posts: 1,860
Hard-core CEG\'er
|
|
Hard-core CEG\'er
Joined: Mar 2001
Posts: 1,860 |
Ben - This product is not the best solution. The ecu will not heat the wire with more than 5v no matter how much you want to believe it. Try your fluke meter with it plugged into the maf and running. It will be .08 roughly at idle and you will never never never cross 5v. I've pegged enough mafs in the past to know for sure.
You spent all that money on a PRP and raptor. Now you want to save $150 by buying a gimmic that will seriously distort your maf transfer function? Do it right, save the money you will spend on dyno time sorting that out and upgrade the maf. The PRP GIVES you the functions for all the mafs, in preloaded fashion no less.
2001 Lincoln LS8
1994 Lexus GS300
|
|
|
|
|
Joined: Aug 2002
Posts: 1,224
Hard-core CEG\'er
|
|
OP
Hard-core CEG\'er
Joined: Aug 2002
Posts: 1,224 |
I can see where you guys are coming from by sticking with a larger stock MAF. You have a rock solid transfer function. There is no chance of a calculation error. BUT you are still stuck with a fixed power level.
I've gotta say that this still sounds like a valid product. I'm an electronics guy and it just makes sense. The MAF measures the speed of the air going through it by varying the current through the MAF wires to keep a constant temperature. That current is then turned into a voltage which the PCM can understand. Because the PCM is a logic device, it can only understand a 0-5 volt range. The manufacturer produces a MAF that will put out a voltage range that corresponds the the car's designed power range. Through normal data logging you will never see anything over 5 volts. The PCM's power supply rail is fixed and it can't read anything higher. Your MAF could put out 50 volts, and the PCM would only see it's maximum of 5.
I bet that if you connected a voltmeter to the MAF and then ran it over it's stock limits, it would definitely go above 5 volts. That is the only way that products like the Mafia and Mafextender can work. I wish I had some kind of industrial leaf blower to test my theory.
It also makes sense to me because you can set your MAF to the exact power output range that you are shooting for. You just multiply your transfer function/slopes by the adjustment factor.
I'm not trying to be cheap. I'm just looking for more/better options. I just think that it's wrong for people to blow something off as a "ricer mod" before actually looking into it.
This mod is basic math. You are doing a linear conversion with either an op-amp or microcontroller. This isn't a cludged fix.
I'm still temped to give it a try with my current low-boost project. I probably wouldn't go with a commercial product like the MAFia. I'll just build a voltage divider using an op-amp. I'm pretty sure I have a couple TL082's laying around. 
BP
Last edited by ButtonPuncher; 04/04/06 10:54 PM.
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list.
|
|
|
|
|
Joined: Aug 2001
Posts: 5,810
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Aug 2001
Posts: 5,810 |
Originally posted by ButtonPuncher:
OK guys hear me out...
The stock MAF puts out more than 5 volts when driven over it's stock flow. 7 volts definitely isn't out of range. Heck, if you regulated it, there's no reason that you couldn't push 9 volts. It is fed battery voltage. Don't believe me? My Fluke doesn't lie...
I'm saying that the Lightning/Cobra/Mustang MAF can be less accurate because you can't size it to your application. It is fixed. With the MAFia you can effectively vary the size of your MAF to fit your power level. That way you aren't wasting any resolution.
The stock Zetec MAF is just under 2.5" I.D.. Theoretically it should flow way more air than I will ever need. (And more power than most of you guys will need.) To quote...
Originally posted by DrFrankenbarge:
So if we go to the limit with 450 hp worth of air you're looking at around a 2.25" OD tube at 450 f/s (Mach .4). So to give yourself a little breathing room 2.5 should easily flow fine for 450hp.
Now say we are using this kit on a decent 2.5L and say we're making about 275 at the crank. For a velocity of 450 f/s you're looking at about a 1.75" OD tube (say 16 gauge wall).
This isn't snakeoil guys. It's a valid product. There isn't any voodoo going on. All that it is doing is scaling a voltage down. Pretty simple and very effective.
BP
Yeah, except that 12v battery voltage is for the sensor heater elements... NOT the sensing circuitry.
The maf works by heating one element and then sensing the change in temperature of the air passing over the second element...or something like that. It requires a heater a second element that has a changing resistance based on this heat change. This is also why the maf is a 3-wire or 4-wire sensor (depending if common or separate grounds) rather than just a 2-wire sensor.
Combined with all the electronics a 5v reference source is passed through the circuit and the varying resistance causes a voltage drop that the pcm compares with its stored data. The maf is calibrated and that calibration data plugged into the pcm. This is why there are so many different maf part numbers.
Ford makes enough mafs for their different cars that one is bound to have a measuring range that is suitable for what you expect to see on your engine. All the plugs are standardized for a given year or series of years. Just plug in, change the transfer function and away you go.
BTW, your aren't improving the resolution by changing the voltage if the pcm is still looking for the same voltage ranges. It will just approximate the closest value.
If your maf worked on a 0-5v scale but your intermediate circuitry allowed you to sense a voltage change down to the hundreths's column that reflected a change in airflow, THEN your resolution is improved. You have just possibly changed the range by changing the operating voltage range; and THAT would mean that your equipment isn't that precise and so therefore you needed a larger voltage range.
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
See My Mods
'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
'06 Mazda5 Touring, 5spd,MTX, Black
|
|
|
|
|
Joined: Aug 2002
Posts: 1,224
Hard-core CEG\'er
|
|
OP
Hard-core CEG\'er
Joined: Aug 2002
Posts: 1,224 |
Originally posted by warmonger:
Combined with all the electronics a 5v reference source is passed through the circuit and the varying resistance causes a voltage drop that the pcm compares with its stored data.
I'm sorry but you're wrong. There is no 5 volt reference. It uses battery voltage. Check out this schematic. It divides the battery voltage across the hot wire and a resistor. All Ford has to do is swap one resistor to change the calibration. Also, if it was limited to 5 volts, I couldn't do this...
I just used my compressed air tank. There you go, 6.522 volts. I also made a movie where it peaked around 7.2 volts. I really can't provide more evidence than that.
Originally posted by warmonger:
BTW, your aren't improving the resolution by changing the voltage if the pcm is still looking for the same voltage ranges. It will just approximate the closest value.
If your maf worked on a 0-5v scale but your intermediate circuitry allowed you to sense a voltage change down to the hundreths's column that reflected a change in airflow, THEN your resolution is improved. You have just possibly changed the range by changing the operating voltage range; and THAT would mean that your equipment isn't that precise and so therefore you needed a larger voltage range.
Sure you're improving resolution! You can increase resolution by either making a smaller MAF look larger or by making a larger MAF look smaller. Let's say that you are using a 90mm Cobra MAF. At your peak horsepower you only generate 3.5volts. You are wasting 1.5volts of resolution. If you scale the 0-3.5volts to 0-5 volts, then recalibrate your PCM for a smaller MAF, your are effectively using the whole MAF's range.
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list.
|
|
|
|
|
Joined: Sep 2000
Posts: 9,602
Hard-core CEG'er
|
|
Hard-core CEG'er
Joined: Sep 2000
Posts: 9,602 |
You do not seem to be getting your head around the fact that the factory MAF (or ANY MAF!) is [B]CALIBRATED[/B] to a specific CFM range to fall within a 5V range. Even if the MAF did output a signal voltage higher the 5V it would be beyond the electronics calibration and be an erratic guesstimate at best.
Hacking the MAF signal within its 5V operational range is not an ideal solution at all. Hacking it outside the calibraion of the electronics is an utter waste of time and money.
2000 SVT #674
13.47 @ 102 - All Motor!
It was not broke; Yet I fixed it anyway.
|
|
|
|
|
Joined: Aug 2002
Posts: 1,224
Hard-core CEG\'er
|
|
OP
Hard-core CEG\'er
Joined: Aug 2002
Posts: 1,224 |
I know that it's calibrated. I've said that multiple times throughout this thread. If you know that calibration you can apply a scaling factor. That is how the MAFia or Mafextender works. The MAF will follow the same curve throughout its entire range. Just because Ford only uses the first 5 volts, doesn't mean that you can't use the next volt or two to expand the range. Yes, there is a limit. It appears to be in the 7 to 7.5volt range. Using an op-amp with a perfectly flat response is a great way to do it. If you don't believe me that this works, and works well, talk to 1turbofocus aka TurboTom on the FocusFanatics forum. BP
Ben ---'96 Contour GL * Zetec ATX * Tan on Black steelies---
+++JRSC M62 Under Construction+++
My big-a$$ mod list.
|
|
|
|
|
