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I have a real quick, important question regarding EEC-V and MAF's. Do I need a reflash or chip if I get a new MAF BUT IT IS THE SAME SIZE? I.E. go from the stock FoMoCo 65mm to an aftermarket 65mm. I know you need to chip or flash if you go to a different size, I need to know if you keep the same size. The reason I ask is if you look at the MAF on an 03 'tec, you will see something strange about the MAF, the sampling tube ISNT centered on the mount. Therefore, the standard issue automotive intake pipe wont bolt directly to the MAF. I know I can get a 65mm MAF from a junk yard or Ebay el cheapo, but I dont want to get a chip if I dont have to. I have pipe sitting on my work table and it fits length wise and thru the fender hole, I have a cone filter on order, but the flange on the engine end of the pipe wont bolt to the friggen MAF! *snarl....*
 

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if the calibrations on the sensor are different, then yes you will have to get a reprogram. I assume the calibrations will be different, or why else would you replace a stock MAF with an aftermarket of the same size?

You can, however, purchase a larger MAF that can be calibrated to match the stock MAF. That way no reprogramming is necessary.
 

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I'm sorry, I didn't read the reason you were changing out your MAF. but it still stands: if the MAF is not calibrated to match stock, then a reprogram is necessary. I would contact the MAF supplier and ask them if it will work.
 

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In theory, silvapain is right. If the calibrations are the same then you don't need a chip or reflash. The theory is that with a Pro-M, for example, you can get a larger MAF calibrated for the stock injectors and it will be fine.

In practice, paces liek Pro-M will skew the air meter to "lean out" the air meter function a bit for "more power" for an N/a car. But this also affects load and timing is now calculated improperly. In some cases, you end up with knock. So in reality, it is best to always get a chip. I made a larger post about this on this forum somewehre, I'm pretty sure, that explains it in detail.

Furthermore, and I know this is not your reason for wanting a new MAF, but on a stock car, a MAF (or a TB for that matter) will NOT net you any gains in the sense of "opening up a restriction" since these items are not a restriction on a stock car. Your car will not flow any more air than it is pulling in, under vacuum, with these two items being "upgraded."

Additionally, most of the time, these CAI's will, because of bends and turns before or after the MAF, skew the air meter function as well, and usually, unless tuned, they will offset any gains you may actually make and in most cases, you will either not gain anything or even lose a little power. Not in all cases, but many times. So I'd just get a K&N filter in yoru stock air box and call it a day.

Anotehr thing to note is to NEVER re-oil these re-usable filters, but rather, toss them and get a new one when they become dirty. Reason is that some oil ALWAYS migrates onto the hotwire on the MAF, no matter how little you use, or how careful you are, and your car will drift lean. Better to buy a new filter than a new engine.
 

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I have the Pro-M 75mm MAF from Draxas on my 96 Duratec. It took them (Pro-M) three tries to get one to me one that even worked. It don't have before/after dynos, but it may even be putting out less power with the larger MAF. We ran my car on the strip at RotB and never got better than 17.3s. Stock Duratec cars were getting 16.5/6 or so. Unfortunately, I did not have the stock MAF with me to swap, so there may be some other problem, but I'm suspecting the calibration leaning tricks may not be doing me any favors.

At the risk of becoming a thread hijacker, since Alberto is discussing chipping for MAFs, I have a question. The answer is possibly relavent to the topic. After I'm through with my current wave of suspension modifications, I will be wanting to get a performance program for my PCM. I already have the 75mm MAF and cone filter intake (not yet in the fenderwell.) Would it be better to:

A) Get the program done for the 75mm MAF w/ since I have the flow sheet calibration data.
B) Get the program done for the stock MAF and continue with the code filter.
C) Like B, but put back the stock air box w/ K&N filter and w/o the intake silencer.

[75mm MAF and stock box is not possible, since the MAF is too long.]
 

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You have to realize that a "larger" MAF really makes no difference just from being larger (with some exceptions that mostly apply to some older 5.0 Mustangs where the MAF on FI actually posed a restricton). This is mostly a marketing thing that has propagated a myth. So for the most part, the relevant thing is really the range in the calibration.

Given the above, I would suggest that option C is probably best. That way, you can sell your MAF. I'll take care of correcting a/f on my end.
 

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You have to realize that a "larger" MAF really makes no difference just from being larger (with some exceptions that mostly apply to some older 5.0 Mustangs where the MAF on FI actually posed a restricton). This is mostly a marketing thing that has propagated a myth. So for the most part, the relevant thing is really the range in the calibration.
Isn't this analagous to two series resistances in electronics. If I consider the stock MAF to be a 10 ohm resistor and the rest of the air path to be a 100 ohm resistor, then the MAF is not the major factor in the total resistance, but reducing it from 10 to 5 would still change the overall from 110 to 105. Those are just numbers pulled out of thin air for example. If it's more like 1 for the MAF and 10,000 for the rest of the air path then the analogy is still technically correct, but the effect of changing the MAF is meaningless, as you said.

Given the above, I would suggest that option C is probably best. That way, you can sell your MAF.
Only to people that haven't read this thread :D
 

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Originally posted by SableOHC@Jun 9 2004, 05:46 PM
Isn't this analagous to two series resistances in electronics. If I consider the stock MAF to be a 10 ohm resistor and the rest of the air path to be a 100 ohm resistor, then the MAF is not the major factor in the total resistance, but reducing it from 10 to 5 would still change the overall from 110 to 105. Those are just numbers pulled out of thin air for example. If it's more like 1 for the MAF and 10,000 for the rest of the air path then the analogy is still technically correct, but the effect of changing the MAF is meaningless, as you said.
I think this is a good analogy. I don't really want to guess at the "resistance" values for the MAF and the rest of the intake. But I think you have the right idea.

AM.com, you didn't get it. The MAF being a resistor is an analogy.
 

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How is that analogy correct?

A restriction or "resistance" since you want to word it that way, is measured by pressure drop after the item.

There is NO pressure drop after the MAF at all, because it is not a restiction whatsoever, so it is not like a resistor. It is not impeding airflow in any way in his car. Substituting a larger MAF still has no effect, and thus does not "lower resistance" any. So there isn't a "resistance" value here at all.

You all need to stop thinking of "bigger maf" to mean physically bigger. It's bigger as in the amount of airflow it will support in its calibration, before it reaches 5 volts and pegs. Since the EEC does not acknowledge any signal from the MAF over 5v, if you do not have enough range, additonal airflow will not be recorded and the car will go lean. This will NEVER happen in an N/A car with a stock MAF.

Selling physically larger MAF's because they "open up the intake" is a marketing tool, just like runing premium fuel burns "cleaner" or is "better for your engine". Sometimes you MAY need a larger MAF over another in an FI setup to mate with the piping used, but for the most part (with the expections of say a 55mm MAF on a bliown 5.0, the hysica size of teh MAF will not matter. An 80mm MAF with a given calibration will work just as well as a 95mm MAF withthe same calibration. Again, what maters in this case is the range of the calibration, i.e. an what airflow level (#/min) it will peg. This may be contrary to popular belief, but this is correct.
 

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There is a pressure drop after the MAF. It may be small, but there will be one. Even a 100mm MAF on a n/a 3.0L will cause a slight drop in pressure after the MAF. I don't know if you can find equipment that is sensitive to measure that pressure drop, but it is there.

You do need to pay attention to both the size of the opening and the calibration. Recalibrating a 55mm MAF to read 5V a 1500kg/hr isn't going to help it flow all that air. It will allow you to measure it, if airflow was that high. But it doesn't make the MAF "bigger".

You need a MAF that is matched (size-wise) to your engine. Then you need it to be calibrated so that you never "peg" the electronics. Then you need the PCM calibration to match the MAF cal.
 

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NO, there actually ISN'T a pressure drop at all. Our testing of vehicles on the dyno, when doing research, is extensive. We sometimes work on a dyno that has an analog input for this and we tap a vacuum hose right after the MAF and record it as data. We actually log this for various cars. Though we have even recorded a 2in/hg pressure drop after a supercharger blower inlet on many cars, and a pressure drop for some stock car's MAF's (the actual ones will be detailed below) on this car, there is absolutely no pressure drop with the stock MAF. Believe it or not, on a supercharged 3.8 Mustang with a 70mm MAF, there ALSO was no pressure drop in this part of the system (the MAF meshed with the piping and the restriction was at the inlet of the blower, NOT the MAF; an this car was clearly flowing a lot more air ~22#/min on a 4v 2000 3.0L Taurus vs 41#/min on the Supercharged 3.8). It is thus hard to imagine that a 70mm MAF will pose a resticiton on a stock 3.0L, and our data confirms this.

A larger MAF will not help by being physically larger, unless the smaller MAF was a restriction.

In this case, you will find very little, if any power in a new MAF over your stock MAF. People will swear and show dyno graphs gaining power but the graphs simply show that a/f has shifter leaner, and the EEC things load is lower, so itt adds a bit of timing becasue of the way the EEC works with the MAF, it will get a little more timing.

If you look at the pressure drop across the MAF, the true indication of restriction, at the air flow that a stock car has, you will find there is no difference in the pressure drop across the MAF and hence no power to be gained.

Now, there are some vehicles where the stock MAF is a restiction, such as the Crown Vic's, and some early Supercoupe's and SHO's. In these applications there is some power to be gained by a larger MAF.

The MAF will flow the air. If it is not a restriction, then making it larger will not get any more air into the engine. Once there are no restrictions, opening up any air passages more than they are will not help, as the engine wil not flow more air than it can pull in. Your assumption is that there is some impedence because the stock MAF is a restriction, but I have shwon above this is not true.

Yes, if you change MAF's you need tomake changes in the EEC. I have made this point onvarious ocassions and touch upon it on my article on our site, which I will link below. But that is not the point here. I am simpy showing that on his car, he will nto flow any more air from changing MAF's, for the reasons detailed above. Not that that isn't self explanatory on it's own, but: mour equipment is unique in tat, unlike most, it allows us to read and record EEC data realtime. We have a databse of data from each and every car we have ever worked on libve, ad we use this to fine-tune our tuning. We have data for many otherwise stock 3.0L Tauruses, with and w/o aftermarket MAF's...and the ones with "larger" MAF's don't flow any more air...the explanation can be found above.

What do you mean "matched size-wise" to your engine?" The only reason you don't, want one with too much more range for your application than you need is because you lose low end resolution...we can match any meter to any injector size in the EEC. As far as size, afetr there is no pressure drop, any physically bigger will yield no additonal power.

Read this, it may make some of the same points you are making:

http://www.americanmotorsport.com/faq.htm#q9

While not on point in it's entirety,. I do touch on the calibration aspect, since you just brought that up, and I didn't want to add that here to confuse the issue.
 

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I can agree 100%, if you change "no pressure drop" to "no significant pressure drop". I personally don't have experience to say if the pressure drop is significant or not. But I do belive you know what you are talking about. Until shown evidence to the contrary, I'll go with insignificant. But I know there is a pressure drop. This is a basic law of physics.

When I say match it "size-wise" I am talking about diameter. Too small, and it will be restrictive. Too large, makes it difficult to get consistant flow thru the sample tube at low RPM.
 

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Our data shows no pressure drop at all in this car. You can log this yourself if you want. Basic laws of physics state that there will always be a presure drop after a bottle neck, when the restriction is alleviated after the obstruction. After the MAF, no alleviation is to be had, because it is not a restriction tobegin with. This is WHY there is NO pressure drop. If there was some, then it would be somewhat restrictive then (wouldn't it?) and there would be *some* power to be gained from a larger MAF. Clearly, the MAF is not a bottleneck.

Yes, if the MAF is too small, it wil be restictive, but this is not matching to engine-size necessarily, but rather, airflow.

I disagee with your comment about "too large." Flow, even of not laminar, will nontheless be consistent across the hotwire, and, as long as calibrated properly in the EEC, the readings will still be accurate. We once had a customers blower break a belt on the dyno (it was a Powerdyne, they have internal belts) and he was able to drive home just fine with our tune, a 90mm MAF on a stock car, and 42# injectors. When he fixed his blower, he just had to mount it back on. Such is the benefit of a good tune. But there is no point in going too big. As shown, most cars nowaways, at least Fords, and certainly the one in discussion, do not have a problem with the stock MAF. Thus, going larger makes no sense.
 

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Originally posted by americanmotorsport.com@Jun 10 2004, 05:58 AM
Our data shows no pressure drop at all in this car. You can log this yourself if you want.
All that tells me is that the pressure drop, was smaller than your equipment can measure. I'm not going to throw away all those hours in physics class, because of what I read here.

Basic laws of physics state that there will always be a presure drop after a bottle neck, when the restriction is alleviated after the obstruction.  After the MAF, no alleviation is to be had, because it is not a restriction tobegin with.  This is WHY there is NO pressure drop.  If there was some, then it would be somewhat restrictive then (wouldn't it?) and there would be *some* power to be gained from a larger MAF.
Yes, if there is a significant restriction, there will be a significant pressure drop, and a significant amount of power that could possibly be gained.

Clearly, the MAF is not a bottleneck.
No, it's not a significant bottleneck.

Yes, if the MAF is too small, it wil be restictive, but this is not matching to engine-size necessarily, but rather, airflow.

I disagee with your comment about "too large."  Flow, even of not laminar, will nontheless be consistent across the hotwire, and, as long as calibrated properly in the EEC, the readings will still be accurate.  We once had a customers blower break a belt on the dyno (it was a Powerdyne, they have internal belts) and he was able to drive home just fine with our tune, a 90mm MAF on a stock car, and 42# injectors.  When he fixed his blower, he just had to mount it back on. Such is the benefit of a good tune.  But there is no point in going too big.  As shown, most cars nowaways, at least Fords, and certainly the one in discussion, do not have a problem with the stock MAF.  Thus, going larger makes no sense.
As an extreme example, lets look at Ed's car.

Ed's car is supercharged. He is pushing 12,358psi of boost (remember this is an extreme example). He needs a 2 foot diameter MAF to get all that air in his engine.

Now if Ed's blower belt were to break, or if you were to put Ed's MAF on a non-supercharged engine, the airflow thru the sample tube would be so low that it is out of the range of what the electronics can measure.

Now if you said that there are no commercially available MAFs that are too large for the Taurus, I'll go along with that.

And I agree about wanting your MAF to be calibrated so that you have the largest resolution at idle, yet still can't "peg" it at 5 volts. That is probably the biggest argument for not putting a larger MAF on, because they are usually calibrated for a higher max airflow.

I don't really know why we are arguing about something that is insignificant.
 

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If you have a drinking straw connected in between two 6' diameter tubes. Your drinking straw is 6 miles long. Each 6' diameter tube is only 6" in length.

Flow air thru it. Are the 6' tubes causing any restriction?

I say they are.
 

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Originally posted by eCarâ„¢+Jun 10 2004, 05:33 AM--><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (eCarâ„¢ @ Jun 10 2004, 05:33 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-americanmotorsport.com@Jun 10 2004, 05:58 AM
Our data shows no pressure drop at all in this car. You can log this yourself if you want.
All that tells me is that the pressure drop, was smaller than your equipment can measure. I'm not going to throw away all those hours in physics class, because of what I read here.

Basic laws of physics state that there will always be a presure drop after a bottle neck, when the restriction is alleviated after the obstruction.  After the MAF, no alleviation is to be had, because it is not a restriction tobegin with.  This is WHY there is NO pressure drop.  If there was some, then it would be somewhat restrictive then (wouldn't it?) and there would be *some* power to be gained from a larger MAF.
Yes, if there is a significant restriction, there will be a significant pressure drop, and a significant amount of power that could possibly be gained.

Clearly, the MAF is not a bottleneck.
No, it's not a significant bottleneck.

Yes, if the MAF is too small, it wil be restictive, but this is not matching to engine-size necessarily, but rather, airflow.

I disagee with your comment about "too large."  Flow, even of not laminar, will nontheless be consistent across the hotwire, and, as long as calibrated properly in the EEC, the readings will still be accurate.  We once had a customers blower break a belt on the dyno (it was a Powerdyne, they have internal belts) and he was able to drive home just fine with our tune, a 90mm MAF on a stock car, and 42# injectors.  When he fixed his blower, he just had to mount it back on. Such is the benefit of a good tune.  But there is no point in going too big.  As shown, most cars nowaways, at least Fords, and certainly the one in discussion, do not have a problem with the stock MAF.  Thus, going larger makes no sense.
As an extreme example, lets look at Ed's car.

Ed's car is supercharged. He is pushing 12,358psi of boost (remember this is an extreme example). He needs a 2 foot diameter MAF to get all that air in his engine.

Now if Ed's blower belt were to break, or if you were to put Ed's MAF on a non-supercharged engine, the airflow thru the sample tube would be so low that it is out of the range of what the electronics can measure.

Now if you said that there are no commercially available MAFs that are too large for the Taurus, I'll go along with that.

And I agree about wanting your MAF to be calibrated so that you have the largest resolution at idle, yet still can't "peg" it at 5 volts. That is probably the biggest argument for not putting a larger MAF on, because they are usually calibrated for a higher max airflow.

I don't really know why we are arguing about something that is insignificant. [/b][/quote]
I think we're all done here. For the most part, I think we agree he will not benefit from a larger MAF, which answers his original question.

We could argue the other points still, but it would not add any value to the issue here. I'm still not sure why you insist there has to be a pressure drop when the MAF tubing is just as large or if it is larger than the induction tubing though, but oh well. BTW, the equipment can measure in extremely small intervals, like if you suck on the sampling tube like a straw, it will show...pretty neat.
 

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Originally posted by eCarâ„¢@Jun 10 2004, 05:41 AM
If you have a drinking straw connected in between two 6' diameter tubes. Your drinking straw is 6 miles long. Each 6' diameter tube is only 6" in length.

Flow air thru it. Are the 6' tubes causing any restriction?

I say they are.
No, but the straw is. You would then see a pressure drop just after the straw, but not before it, becasue you could measure vaccum after the straw.
 

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Originally posted by americanmotorsport.com+Jun 10 2004, 06:50 AM--><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (americanmotorsport.com @ Jun 10 2004, 06:50 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-eCarâ„¢@Jun 10 2004, 05:41 AM
If you have a drinking straw connected in between two 6' diameter tubes. Your drinking straw is 6 miles long. Each 6' diameter tube is only 6" in length.

Flow air thru it. Are the 6' tubes causing any restriction?

I say they are.
No, but the straw is. You would then see a pressure drop just after the straw, but not before it, becasue you could measure vaccum after the straw. [/b][/quote]
If your measuring equipment is good enough, you will measure a pressure drop 1" from the opening of the first 6' tube, and a slightly larger pressure drop at each interval farther down the tube. There will be a big pressure drop right after the opening of the straw. There will be a small pressure drop 1" down the straw, and a small drop at each interval down the length of the straw. There will be a big pressure increase after you leave the straw and are in the last 6' tube, but will be a lower pressure than you had before you entered the straw. At each interval on your way to the end of the last 6' tube there will be a small pressure drop.

It doesn't matter that there are no instruments on the planet that can measure the small pressure drops that I am talking about. They are still there.

I'm sorry to be busting your balls like this. Don't think that I'm trying to say that you don't know what you are talking about. I think you know exactly what you need to know. It doesn't matter that you don't grasp this concept. But, if you don't believe me, a physics text will clear it up. I really don't have the qualifications to teach.
 

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Dude, you're not the only engineer here...and you're wrong. It is you who have your concepts confused. You should simulate your own test, and measure, then let me know...


You will find a large pressure DROP (vaccum) where the straw meets the large tube, and NOT at the end of the tube that feeds into the straw not at the beginning of the straw where it meets this same tube.
 
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