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Discussion Starter #1
Just finished porting my stock Cobra mass air meter (70mm).

First I took a metal hacksaw blade and cut out the center post. It probably blocks 1/4 of the airflow capacity of the meter. Be sure to cut very close to the wall of the meter. The cutting went really fast. Then I took some coarse sandpaper and sanded down the areas I cut, and pretty much the whole thing (it's real smooth). Then I cleaned all the metal flake off and wiped the meter down with a rag sprayed with a little WD-40. I also carefully cleaned the wires of the meter with some rubbing alchoal and quetips. They had a layer of black whatever on them, but came clean. Also cleaned my throttle body, intake hose, and all MAF connectors while it was apart.

I also put the screen back on the meter, I've had it off for a while. I'm questioning if I should leave it off now. Maybe next time I mess with it. Supposedly it smooths the airflow, but I don't think it does much of anything but block more airflow.

I haven't noticed any difference in driveability or performance, but I'm not good at noticing small gains. Any difference could also be due to the battery being disconnected (computer memory being erased and hasn't been fully relearned just yet).

Here's the instructions I used on how to do it. They are written for a 4.6L but are basically the same for our cars:

http://www.corral.net/tech/powerplant/mafgut.htm

And here's what it looks like now:



Now I'm off to bypass my smog-pump and gut my catalytic converters. : )

"Necessity is the mother of invention".

IJCobra
 

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Discussion Starter #3 (Edited)
Nope. The instructions didn't say to. I thought about it, but didn't want to screw it up.

I figured the sampling tube size / wires were calibrated for each other. I did not want to mess with going lean or rich.

It'd be easy to port it tho. Take about 10 minutes and a long skinny round file.

IJ
 

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IJCOBRA said:
Nope. The instructions didn't say to. I thought about it, but didn't want to screw it up.

I figured the sampling tube size / wires were calibrated for each other. I did not want to mess with going lean or rich.

It'd be easy to port it tho. Take about 10 minutes and a long skinny round file.

IJ
by removing the center post, you allow more airflow through the MAS. porting the sampling tube will allow more airflow to cool the hotwires, which will trigger more fuel to match the increased airflow through the MAS.
check this link:
http://www.mn12performance.com/mn12how-to/maf/maf.htm
 

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I just had an opportunity to compare a ported MAF with a non-ported when I got my 95. I had a ported one in the garage and swapped it in. (No modification of the sampling tube) As soon as I drove the car it started to detonate under hard acceleration, I would guess due to the additional airflow. This was on a cool night too. I put the stocker back in and no detonation. I put my Pro-m 75 on and no detonation. IMHO, unless you can tune for the additional aiflow or have the MAF electronics recal'd it will cause more problems than it cures.
 

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While I dont doubt that it has caused detonation is SOME cars, i have done it to two different mustangs with no problem what so ever. Ford has never been known to tune to the "jagged edge", so in a lot of cases, i thing that gains can be achieved. You dont know until you try. If it detonates, then buy a used one on the corral for $20. I have two extras right now.

Gary
 

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Discussion Starter #7
Thanks BoneStock. If I have any problems, I'll drill out the sampling tube a little.

No problems yet, even on 87 octaine. My timing is set at what came from the factory tho.

I don't have a chip either. I figure Ford makes these cars run a little rich anyways, so even if it leans it out a little it could actually be making the mixture more optimum.

?
 

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Actually Ford tunes them lean for emissions purposes
 

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Discussion Starter #9
I drove it today and it seems stronger than usual. : )
 

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I ported mine 2.5 years ago, and its still fine. Running a 70TB with Cobra Intake and heads now. Never had an idle problem or anything. I run a Mac CAI also and no problems. If your wires had black soot on them that can cause a lean condition about 30% is what the Pro-M people say. I run at higher elevation than most of you but I did have the car down at sea level and other than dropping my timing back 2 degrees the car ran super! I am hesitant to put anything else(maf) on the car in fear of causing problems that I have heard about. Pro M says not to put a bend in front of theirs or try to turn it till the idle corrects. I agree with "Yellow95". I do plan on a bigger maf but not untill I update to 24's and bigger fuel pump. I havent experienced any problems with my mods and my stock computer yet. So far so good!;)
 

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I have a cold air intake with a 90 in it in front of my Pro-M. But Pro-m calibrated the meter to accomodate it. It has WMS (Western Motorsports...my cold air) etched on the top of the meter. They even had one there so I didn't have to send mine in. Never problem 1 with it.
 

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90 degree elbow going out into the fenderwell I assume? Thats good to know. "TJ", what Pro-M you running? Do you just tell them what you are running in front of it like the elbow and they can set it up that way??:confused:
 

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Devils advocate here:


Porting the MAF will make more power both because it runs leaner and more air/less restriction. If you already bumped the timing up it may ping and then may have to back off the timing. On a SC car this can melt the cats/damage O2 sensors and cause much worse pinging. Also a leaner burn may create more NOx, No not NOS, and not pass emissions. Just be aware.:evil:

BTW: Clean job on the porting
 

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Discussion Starter #15
Driving the car around today, I could noticabily tell the difference. My car seemed to have more grunt. Ran stronger than usual.

I guess the computer re-calibrated itself by now.

I'm pretty happy with this mod, it was better than I planned.

I just wish I had some dyno #'s to see what kind of gain I got.

Not too bad for a $20 stock Mass Air Meter.
 

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TJ 94gt vert said:
I have a cold air intake with a 90 in it in front of my Pro-M. But Pro-m calibrated the meter to accomodate it.
calibrated for what? your sensor senses air, and signals for the fuel to match it. the only thing to calibrate for is heavier injectors.
 

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Well when I ordered the Pro-M 75, they asked me if I was running a CAI. They stocked the different types inhouse and calibrated the output to compensate for the 90 degree bend in front of the MAF. Here me now, believe me later. Maybe they just etched WMS on the top of the electronics to make me feel better but I have never experienced any of the problems associated with the elbow that others have reported. As far as "what calibration", they can change the output to compensate for injectors, flow characteristics etc, as long as they know what you have and they can flow the MAF with it hooked up to whatever it is.
 

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Question: How many other sensors on a car do you de-calibrate to make the car peform better?

Answer: I don't know of any.

Porting the sample tube does not help the situation. In fact it may even lean the mixture some more. Here's why:

The elements in the sample tube require air flow to cool them. The MAF/computer will calculate how much air is there by how cool the element actually gets. There's more to it but that's basic.

Now if you port the MAF you are allowing more air in. But as mentioned your not telling the computer that. Mixture goes leaner. So you port the sample tube. Yup that lets more air in the tube. But the surface area and programming of the electronic portion of the MAF didn't change. So letting more air in by increasing diameter doesn't affect the cooling of the elements. What affects the cooling of the elements is the velocity of the air. If you want to increase velocity of the air you'll want to make the diameter of the sample tube smaller.

Porting MAFs IMHO is voodoo. The results will be unpredicable and unreliable. The stock MAFs will flow way more air than most engines will need before the post actually becomes a restriction. The post is there to prevent irratic idle and stalling.

BTW, I too ported my MAF and my car got lean as crap. Had to replace it.

Ed
 

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Discussion Starter #19
I'm happy as hell with it now.

Car is running better than it ever has!

Mind you it is totally stock except for the ported MAF. I'm talking, no cat-back, not even a K&N. (Dynomax on order).

Perhaps I'll begin to notice a negative change with further modification, but for now it rocks!
 

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I ported mine a few months ago, and had no idle problems, but noticed pinging at WOT. It turned out that my balancer had also slipped, and my timing was off. I have replaced my balancer and retimed my car back to 10 deg. I still was getting pinging in warm weather at WOT, so last night I ported the sample tube per some instructions I saw, with a 15/32 drill, and disconnected the battery for an hour to allow resetting of computer. Today, on the way home from work, on the freeway, I floored it in 3rd and 4th, and again noticed pinging, but only for a moment, then it seemed to go away. I will try again tomorrow and see. Here is a link with what appears to be some good information, and frowns upon MAF porting.

Hope it helps!

Gary

http://www.flash.net/~rfm2/massair.htm
 
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