80mm MAF Sensor for SOHC V6

I'm confident that Ford engineering devoted a lot of effort to improving the performance of the 4.0L SOHC V6 as evidenced by the upper and lower intake manifolds and intake air plenum. However, the performance potential cannot be achieved with the numerous airflow restrictions in the rest of the intake system.

My long term plan is maintain or increase the velocity of the intake air as it travels to the plenum.

Currently on my Sport the worst airflow bottleneck is the 1 3/4 inch internal diameter silencer on the air filter enclosure. I plan to eliminate this restriction soon with my own version of the "swiss cheese mod" and the incorporation of a high flow air filter.

The next worst bottleneck is the stock MAF sensor. To comply with my long term plan the internal diameter of the MAF should be between 3.5 and 3.0 inches. An 80mm (3.15 inch) MAF would be ideal. Since I'm more concerned with improving efficiency than increasing horsepower I want to maintain the stock air/fuel ratio and if possible not reprogram the PCM. Also, I want to have an integrated MAF and intake air temperature unit (6 wire connector).

Has anyone had good results replacing their stock Explorer SOHC MAF with an 80mm MAF and made no other mods? If so, who manufactured the MAF?

2000StreetRod said:

I'm confident that Ford engineering devoted a lot of effort to improving the performance of the 4.0L SOHC V6 as evidenced by the upper and lower intake manifolds and intake air plenum. However, the performance potential cannot be achieved with the numerous airflow restrictions in the rest of the intake system.

My long term plan is maintain or increase the velocity of the intake air as it travels to the plenum.

Currently on my Sport the worst airflow bottleneck is the 1 3/4 inch internal diameter silencer on the air filter enclosure. I plan to eliminate this restriction soon with my own version of the "swiss cheese mod" and the incorporation of a high flow air filter.

Has anyone had good results replacing their stock Explorer SOHC MAF with an 80mm MAF and made no other mods? If so, who manufactured the MAF?

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I don't know how much this will help...

BUT, I have done many of these things on my 2002 Ford Crown Victoria LX. Now, granted, it has a 4.6 liter V8. But when I first got the car, I was lucky if it ran the quarter in a 16.5. It had single exhuast, restrictive intake, blah blah...

I went to Blue Oval Chips (the guy's name is Lonnie). The Crown Vic guys have all gone to 80mm MAFs as the real common "upgrade".

For most of us, (pre 08 guys), we upgrade our cars to the Mercury Marauder air box, with the 80mm mass air flow sensor. The ECM needs to be reflashed so that it recognizes that it has an 80mm MAF on it, but stock for stock, we typically see a 25 hp increase.

Now, I don't know what a 4.0 SOHC has stock, but I would guess that unless you had some major major modifications, that 80mm would be overkill.

I would say that 70mm is probably more than enough.

As for the air box, I haven't looked at the opening in my own, but it's usually not the size of the actual opening that's the problem, but the total surface area of filter that can become the restriction. What I'm saying is... if you had a MASSIVE air box, with a filter that was literally like a 2'x2' and the normal factory opening, you probably wouldn't have a restriction. As it stands, the filter size could probably be improved.

Luckily for Crown Victoria owners, the Marauder airbox simply bolts RIGHT in place of the factory one, and looks totally stock. There's no "SS" or "MegaUltra" version of the Ford Explorer Sport, so we're kind of out of luck there, but that's my thoughts. It's the filter rather than the opening. For what it's worth though, the opening on the marauder air box is ever so slightly larger, but it protrudes further into the grill to take it's air.

Also, the Crown Victoria's 4.6 benefits greatly by the porting of the intake plenum.

I think headers, and the magnaflow cat pipes are probably really beneficial to the motor's top-end at least.


The Exploder is a lot like the Vic in that it benefits from increased low-end torque to get it moving. So I would focus my improvments on that.

I'm going to be upgrading my own Explorer in the months to come...


Oh, just wanted to mention that my Crown Victoria will break into the high 14s when the stars and the planets align, but it runs consistent flat 15s all day long, yet it still maintains it's very calm demeanor when I drive around normally. But when I floor it...

2000StreetRod said:

... I'm more concerned with improving efficiency than increasing horsepower I want to maintain the stock air/fuel ratio and if possible not reprogram the PCM....

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The best power and fuel economy will come from new PCM programming, so pencil that down at the top of the list. Try to do it last with something that has to have it like a MAF.

The MAF can't be changed without reprogramming the PCM(not counting the wrong way with "calibrated" MAF's).

A MAf doesn't need to be small or moderate in size, if you change make it plenty big, the 90mm Lightning MAF(LMAF) is very common and works great. Others have Explorers with the LMAF and a flasher like the SCT ExCal's.

Look for a 4.6 throttle body at some time also, I'd do a 75mm TB if I did it again. The intake manifold is a restriction, so you can't do much for the SOHC other than the air cleaner/MAF/TB, and exhaust. With an electric fan and other things you should get just over 200rwhp. Regards,

I've done a little more internet research and learned that my stock MAF sensor has an internal diameter of 55 mm and is good up to around 550 cfm. 55 mm computes to a cross sectional area of 3.68 square inches. 80 mm computes to a cross sectional area of 7.79 sq in or 2.1 times the area of the 55 mm. I agree that an 80 mm MAF has an airflow capacity much greater than my normally aspirated 4.0L could ever use. However, I'm interested in reducing airflow restrictions to increase efficiency.

The velocity of the airflow thru the 80 mm will be about half that thru the 55 mm. Obviously, something must be done to make the 80 mm compatible with the PCM. Doubling the injector pressure might be one possibility but I prefer an electrical solution. I'm thinking about plotting the voltage vs rpm for my 55 mm and then trying to design an electrical converter for the 80 mm. One reason is that my 55 mm MAF has an intake air temp sensor (six wire connector). Does anyone know of an 80 mm MAF with an intake air temp sensor?

Edelbrock put their Racing Sports Akimoto air cleaner on sale for $9.95. At that price I bought two for evaluation purposes. It is used with their turbo kits for Hondas with up to 400 horsepower so it shouldn't be too restrictive even though the outlet diameter is only 3 inches.

I'm scheduled for dyno testing this afternoon. I hope to establish my stock performance (baseline). Then I'll measure changes due to my throttle cable mod and the high flow air cleaner. I also plan to measure the air conditioner performance degradation.

The 80mm MAF will be too big. I'm using an 80mm Lightning MAF on my '94 Cobra with a Vortech blown 302 that makes 471rwhp. I think that you will have tuning issues if you try to go that big. I think a 70mm will be plenty big for your application but I would check with your tuner.

2000StreetRod said:

I've done a little more internet research and learned that my stock MAF sensor has an internal diameter of 55 mm and is good up to around 550 cfm. 55 mm computes to a cross sectional area of 3.68 square inches. 80 mm computes to a cross sectional area of 7.79 sq in or 2.1 times the area of the 55 mm. I agree that an 80 mm MAF has an airflow capacity much greater than my normally aspirated 4.0L could ever use. However, I'm interested in reducing airflow restrictions to increase efficiency.

The velocity of the airflow thru the 80 mm will be about half that thru the 55 mm. Obviously, something must be done to make the 80 mm compatible with the PCM. Doubling the injector pressure might be one possibility but I prefer an electrical solution. I'm thinking about plotting the voltage vs rpm for my 55 mm and then trying to design an electrical converter for the 80 mm. One reason is that my 55 mm MAF has an intake air temp sensor (six wire connector). Does anyone know of an 80 mm MAF with an intake air temp sensor?

Edelbrock put their Racing Sports Akimoto air cleaner on sale for $9.95. At that price I bought two for evaluation purposes. It is used with their turbo kits for Hondas with up to 400 horsepower so it shouldn't be too restrictive even though the outlet diameter is only 3 inches.

I'm scheduled for dyno testing this afternoon. I hope to establish my stock performance (baseline). Then I'll measure changes due to my throttle cable mod and the high flow air cleaner. I also plan to measure the air conditioner performance degradation.

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I admire your engineering / determination to resolve the problem. That said, I highly recommend that you go with an ECM reflash. Unless you're just looking at this in terms of a challenge, and that's what you want... then I recommend a reflash.

There are places (Blue Oval Chips, ExplorerExpress) who do this kind of thing on a regular basis and have the optimal programming for speed / efficiency for your motor / configuration. I would highly recommend you just go with a 70mm... it will resolve any restrictive issues you may have anyway, but it's a VERY simple change that they perform with the ECM reflash.

As it stands, when you buy the ECM reflash from one of these guys, you also get the tuner which ALLOWS you to reflash the car any time you want, and with whatever changes YOU want. They sell you the device with their own programming in it.

When I went with Lonnie on for the Crown Vic, he adjusted timing, rpm, etc. The shift points on my Crown Victoria are slightly higher, and he increased the line pressure on the tranny at wide open throttle shifts. It's great because with normal driving, the Crown Victoria feels like your run of the mill stock Grandpa car. But when I nail that gas, the tires break loose, and the shift is SOOOO hard that if my wife isn't wearing her seatbelt (she always does), she'll go flying into the back seat. It breaks the tires loose in the shift from 1st to 2nd, and that's even with my 2.73:1 gears and brand new tires.

The ECM reflash is worth the $300 bucks. You can get a 70mm maf for cheap (since 4.6 guys usually replace them with larger MAFs). You'll see a huge difference and a significant improvement.

So, like I'm saying, unless you're looking forward to the challenge of determining the exact difference in voltage / resistance of the MAF and putting a resistor in-line... you're much better off just going with a 70mm and a reflash.

rjcooperss396 said:

The 80mm MAF will be too big. I'm using an 80mm Lightning MAF on my '94 Cobra with a Vortech blown 302 that makes 471rwhp. I think that you will have tuning issues if you try to go that big. I think a 70mm will be plenty big for your application but I would check with your tuner.

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I discussed the 80 mm swap with Mark at Stable Performance who did my dyno testing this afternoon. He said that the stock program could probably handle a MAF increase to 70 mm (might have to increase the voltage upper limit in the PCM) but that some kind of mod would definitely be required for the 80 mm MAF. He suspects that an 80 mm might be worth the effort (better gas mileage) due to a further reduction of air flow restriction. Apparently increasing the fuel pressure or injector size (19 lb to 22 or 24lb) is the normal method to accomodate a significantly larger MAF.

Here's some preliminary dyno results. I ran into problems trying to test in 4th gear (1:1). Mark easily avoided the downshift issues but could not easily work around the 105 mph speed limiter in my PCM that I was not aware of. The work around was to conduct many of the tests in 2nd (1.86:1) to cover the full horsepower/torque curve. I'll try to scale the 2nd gear test results to the limited 4th gear results for the actual numbers to be correct.

Analysis of the plots shows:
throttle cable mod = 8 to 10 hp gain at peak
high flow air filter = 8 to 10 hp gain at peak
A/C compressor hot wired on = 20 hp loss at peak
Time to speed (105 mph) test in DRIVE = 2 secs decrease after mods

You really should plan for a new PCM program, and the SCT ExCal is the best choice to do it. Contact James here about it, he is a very experienced programmer of the Explorers and the ExCal's. He is a sponsor and has done most of the trucks that you read about in here which are highly modified.

About the MAF size, ignore the smaller is better crap. Literally that is wasteful thinking. The key is to only use a high quality MAF(high quality signal), not the cheap aftermarket "altered" MAF's.

The LMAF plugs right into our MAF connector, the inlet size doesn't bolt to the stock air cleaner though, nor do others. Get the big MAF, the LMAF is almost always on eBay for $50 every day.

Contact James(Henson Performance, bottom of page), and see what ExCal's he has now, he often has used models. Plan you modifications, get those done except for the MAF, then do the MAF and flasher last.

CDW6212R said:

About the MAF size, ignore the smaller is better crap. Literally that is wasteful thinking. The key is to only use a high quality MAF(high quality signal), not the cheap aftermarket "altered" MAF's.

The LMAF plugs right into our MAF connector, the inlet size doesn't bolt to the stock air cleaner though, nor do others. Get the big MAF, the LMAF is almost always on eBay for $50 every day.

Contact James(Henson Performance, bottom of page), and see what ExCal's he has now, he often has used models. Plan you modifications, get those done except for the MAF, then do the MAF and flasher last.

Click to expand...

By LMAF are you referring to the Ford Racing Lightning MAF, P/N M-12579-L54? It appears to have the integrated intake air temp sensor (IAT) and the same 6 wire connector. The cross sectional area of the 90 mm would be about 2.7 times (.37 velocity) that of my 55 mm. I've read that there are only 30 data points available in my PCM for the MAF voltage. If I assume the MAF voltage is linear and ranges to 4.7 volts for a normally aspirated max air flow then on my engine it would never go above 1.74 volts (4.7 * .37). However, I believe the Cobra Lightning is a blown intake (prior to MAF) motor which means the MAF voltage in my application would be even less. Running at the bottom fifth of the 90 mm MAF range might significantly degrade air flow resolution.

There are dozens or countless people using the LMAF successfully, as I alluded to before.

The key with any MAF is that the voltage curve be linear, that way programming easily applies the data points to the rpm curve. That's why you should avoid certain MAF's, or the calibrated MAF's. Those have poor voltage curves, and that makes it hell to tune the PCM for even the pros. Ask James about it, he will tell you how good the LMAF is.

I suggested it because it seems to be the most common to find, and for $50 all the time. You have to reprogram the PCm for any MAF change, so get one that you know is very good, and reasonable. Any OEM Ford MAF will be a quality piece, pick one that plugs in and that you can buy easily.

Don't over think the idea, it works, tons of different MAF's will work. TURDLE here had a LMAF on his 347 for a couple of years before getting it tuned. He had some MAF signal tuning contraption, it ran but not great like now with a PCM tune. That's the only one quickly I think of with that MAF right now here.

CDW6212R said:

I suggested it because it seems to be the most common to find, and for $50 all the time. You have to reprogram the PCm for any MAF change, so get one that you know is very good, and reasonable. Any OEM Ford MAF will be a quality piece, pick one that plugs in and that you can buy easily.

Don't over think the idea, it works, tons of different MAF's will work. TURDLE here had a LMAF on his 347 for a couple of years before getting it tuned. He had some MAF signal tuning contraption, it ran but not great like now with a PCM tune. That's the only one quickly I think of with that MAF right now here.

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OK Don, you finally convinced me! I just ordered a new Ford Racing Lightning F150 MAF listed on eBay. It was $65 plus $10 for shipping (not $50) but still a lot less than $200 to $300. I also bid on a Cobra used 80 mm MAF that comes with a connector & cable.

Now I need to find a 90 mm adapter, a 4 inch air filter, and some tubing. Fortunately, I haven't started the mod to my air cleaner housing to accomodate a 3.5 in diameter tube which now will be 4 in.

Being an engineer I'm sometimes cursed with over analyzing. For the near future, I may be "one of those with a MAF signal tuning contraption" of my own design. Probably at least until I complete my cold air intake and my throttle body upgrade. After that I'll probably end up buying one of those "reprogram things" and a "tune" from one of the experts.

You will like the LMAF once you get it in and new programming done. I wouldn't even install it though until you get the real programming with a flasher. I'd work harder on finding one of those for a reasonable price. Touch base with James and let him know what you have and are looking for. he helps with the Explorers all the time, and his SOHC turbo Sport is about the fastest currently here.

The MAF "enhancer" I think it was that Jon had, he had to use it or else not drive the truck. He swapped to the bigger 347 engine so he needed bigger injectors and PCM tuning. He got away without the PCM work for a long time, but he limited the throttle blade and fought driveability issues. After the fact he regrets waiting so long to get it right.

You truck will run better with the stock MAF than any other MAF, until the PCM programming is changed for the new MAF. There are several other things that you can do which don't require the PCM work, they don't reduce driveability. If you do the little things first, then the PCM programming really wakes it all up.

Check out the many threads of Al Aldive, he has done almost everything to his SOHC truck. Ask questions about things which aren't clear. I already mentioned that the TB can be made larger to about 75mm, or the size limit of the intake inlet. Keep an eye out for a good 4.6 TB, and adjust the cable when you get it on.

CDW6212R said:

You really should plan for a new PCM program, and the SCT ExCal is the best choice to do it. Contact James here about it, he is a very experienced programmer of the Explorers and the ExCal's. He is a sponsor and has done most of the trucks that you read about in here which are highly modified.

About the MAF size, ignore the smaller is better crap. Literally that is wasteful thinking. The key is to only use a high quality MAF(high quality signal), not the cheap aftermarket "altered" MAF's.

The LMAF plugs right into our MAF connector, the inlet size doesn't bolt to the stock air cleaner though, nor do others. Get the big MAF, the LMAF is almost always on eBay for $50 every day.

Contact James(Henson Performance, bottom of page), and see what ExCal's he has now, he often has used models. Plan you modifications, get those done except for the MAF, then do the MAF and flasher last.

Click to expand...

Hmmm. Your adamant support for the 90mm LMAF, and mentioning James is an odd combo. It was James that actually expained to me, in detail, why a 90mm LMAF is WAY to big for a non-turbo ro supercharged 4.0L SOHC. Basically, it has way more Add-counts than a N/A SOHC will ever use, so your are trading lower flow response/ resolution for a top-end capability you can never use. I was told that it would affect off-idle, and low-mid range driveability. He told me that even the 80mm was probably of vey limited benefit, if at all.

To the O.P., you mention several times about reducing intake flow velocity as a goal. That's the last thing you want to do intentionally.

I would highly recommend you talk to James before you buy or do anything else. Otherwise, you may end up with a less than ideal parts combo, or even a bunch of expensive parts you can't use.

As someone else has pointed out, you're really trying to go about this the hard way. Forget trying to alter voltage curves,etc.... Just get an Xcal from a good custom tuner, after thoroughly discussing your mods with them.

Good Luck

James knows his stuff, I respect his opinions greatly. He is likely correct about there being limited gains with a 90mm MAF versus an 80mm MAF. But the potential gain is there, and I suggested it from knowing the high quaility of the LMAF, and low cost. If the 80mm MAF you mentioned is as good as the LMAF(I'd ask James), I agree that would work about as well as the LMAF. If we were debating a 70mm MAF versus an 80mm MAF, I'd passionately say don't waste money on the 70mm MAF. That was a common discussion back in the 90's with Mustang 302's.

Quality and cost need to be the biggest factors, and usually in a MAF discussion those don't get mentioned much. If given those two choices, I'd pick the one that will fill the ultimate goals for airflow. Neither is a bad choice, but depending on future needs, I have to leave that to the owner or the pro to say. Regards,

Carguy3J said:

It was James that actually expained to me, in detail, why a 90mm LMAF is WAY to big for a non-turbo ro supercharged 4.0L SOHC. Basically, it has way more Add-counts than a N/A SOHC will ever use, so your are trading lower flow response/ resolution for a top-end capability you can never use. I was told that it would affect off-idle, and low-mid range driveability. He told me that even the 80mm was probably of vey limited benefit, if at all.

To the O.P., you mention several times about reducing intake flow velocity as a goal. That's the last thing you want to do intentionally.

I would highly recommend you talk to James before you buy or do anything else. Otherwise, you may end up with a less than ideal parts combo, or even a bunch of expensive parts you can't use.

As someone else has pointed out, you're really trying to go about this the hard way. Forget trying to alter voltage curves,etc.... Just get an Xcal from a good custom tuner, after thoroughly discussing your mods with them.
Good Luck

Click to expand...

I'm confused by your comment about reducing intake flow velocity. My goal is to reduce cross sectional area as the air proceeds from air filter to intake plenum which will result in an increase in the flow velocity.

I agree that a 90mm LMAF sensor has an airflow capacity that greatly exceeds the SOHC's normally aspirated airflow capacity and that MAF sensor low airflow resolution will be reduced. It may not be possible with an "electronic gadget" to adequately compensate for the resolution reduction but it sounds to me like an interesting experiment.

I appreciate your advice!

CDW6212R said:

James knows his stuff, I respect his opinions greatly. He is likely correct about there being limited gains with a 90mm MAF versus an 80mm MAF. But the potential gain is there, and I suggested it from knowing the high quaility of the LMAF, and low cost. If the 80mm MAF you mentioned is as good as the LMAF(I'd ask James), I agree that would work about as well as the LMAF. If we were debating a 70mm MAF versus an 80mm MAF, I'd passionately say don't waste money on the 70mm MAF. That was a common discussion back in the 90's with Mustang 302's.

Quality and cost need to be the biggest factors, and usually in a MAF discussion those don't get mentioned much. If given those two choices, I'd pick the one that will fill the ultimate goals for airflow. Neither is a bad choice, but depending on future needs, I have to leave that to the owner or the pro to say. Regards,

Click to expand...

There is an 80mm lightning maf too, it's from the 1st gen I think, not sure if it's plug and play but I know there are a least a couple of guys on here using it.

I think I'd hunt the 80mm for my SOHC if it was feasible, and I'm still using the stock MAF.

I'm hoping to be able to upgrade my SOHC to my old 302 if things work out, so I'm not looking to change much now. Please keep us apprised of how your choices wok out for economy. Regards,

techieman33 said:

There is an 80mm lightning maf too, it's from the 1st gen I think, not sure if it's plug and play but I know there are a least a couple of guys on here using it.

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Before I spoke to James, I had purchased a 90mm LMAF, that has never left the box it came in....
He told me about an 80mm, from, if I remember right, '96-'02 4.6L Mustang GT or Cobra. It's still a 6 wire, with the integrated IAT sensor. I actually got one out of a V10 Triton equipped Econoline van ( thanks to the Hollander interchange) This is plug-and play, from a wire harness stand point, but obviously tuning will be required when I install it.

Very good, make a thread and post some pictures to show the differences. How do they differ in mounting at the air cleaner etc? Night,

2000StreetRod said:

I'm confused by your comment about reducing intake flow velocity. My goal is to reduce cross sectional area as the air proceeds from air filter to intake plenum which will result in an increase in the flow velocity.

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I thought I had read in one of your posts that your goal was to REDUCE flow velocity. Maybe a misread something.

I agree that a 90mm LMAF sensor has an airflow capacity that greatly exceeds the SOHC's normally aspirated airflow capacity and that MAF sensor low airflow resolution will be reduced. It may not be possible with an "electronic gadget" to adequately compensate for the resolution reduction but it sounds to me like an interesting experiment.

I appreciate your advice!

Click to expand...

I appreciate your appreciation.

Well, I guess if you just want to tinker, then go for it. But since you already agree that the 90mm MAF GREATLY exceeds the SOHC's airflow potential, and that low flow sensor resolution will be reduced, then why waste your time trying to solve a problem that you will be creating yourself, particularily since their will be no upside to it. I think the 80mm is a worthy experiment. The 90mm, unless you are doing a turbo or blower, is a waste of your time and talents. If you want to "try" things, in the name of fuel economy, power, or just because; I would suggest investing the time and money in something more productive, such as an SCT XCAL w/ the ProRacer Software, and learn how to do your own tuning. That's next on my list. In terms of parts, the money you spend on the 90mm, or even an 80mm MAF would probably be better directed towards optimizing other parts of the package first:

1.) XCAL w/ custom tuning (The tune can always be updated later for further mods, don't wait.) With no other mods, when I installed the tune from James, it was like a whole 'nother truck. The trans tuning alone was worth it)

2.) Cat-back exhaust. Before you worry about getting more air in, you need to make sure it can get out. The stock exhaust, particularly the rear portion (muffler/tailpipe) is a major restriction, even for the stock motor. I have also removed (not gutted-that's bad) my cats (but hid the section of straight pipe inside the stock heat shields), but we're not allowed to talk about that, apparently.

3.) Cold air intake. Personally, I have a K&N FIPK, but you could probably do just as good with a cone filter (K&N, AEM,etc..) and some creative use of SCHD 40 PVC pipe; especially if you will be doing the TB and MAF, as the K&N tube is smaller than both.

4.) Underdrive Crank Pulley (see ALdive's thread)

5.) electric fan

6.)70mm TB

7.) Ok, now it might be time to play with the 80mm MAF