Who is running an aftermarket MAF?

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Who has one of these MAF's?

Has anyone used the 80MM or 90MM lightning MAF? I know it makes a HUGE diffrence on V8 Tbirds and Super Coupes. The only catch is you need a jerry chip (no longer available)


any opinions?
Brian

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ok, this is a technical board, so let's get technical.

Inside the EEC is an air meter transfer function. In the 93-95 Marks, the units are volts vrs #/mass per clock tic. This is a very critical function for EEC. I'll touch on this a bit later.

The 93-95 Mark's are set up from Ford to run very rich. They will command about 10.5:1 a/f ratio at 6000 rpm. This is very rich, obviously. You give up a bunch of power being this rich.

The correct way to make it not this rich is to change the chip so you don't command an air-fuel ratio that rich. The other way (the BAD way), is to change the air meter itself and skew it lean when you get to the higher voltage range. If the engine (EEC) thinks it has less air coming into it, since you've now lied to the EEC by change the electronics of the air meter and not telling the EEC, it will put in less fuel.

This is how the gain is seen with just an air meter. The meter is setup so that it's flow range, meaning the air flow at 5 volts, is more than it use to be. So, at the same air flow, you now have less voltage. This makes it lean, the EEC thinks you have less air than it really does, because the voltage is lower at the same air flow.

So, you sell a different air meter with a different curve, lean the motor out to where it should be, and you gain power, and all of a sudden your "insert buzzword here" air meter makes power. But how much would just a bigger air meter make.

First off, 900 cfm will support about 700-800 HP. If you look at the pressure drop across the air meter based on the air flow of one of these motors, the air meter is worth about a whopping 3-5 HP. You can get this with a slightly different meter for a fraction of the cost. The Mark uses an air meter with a full cross bar, there are meters that have the partial, tonsil looking, cross bar, that have the same air meter transfer fucntion as your meter right now, and you get almost the same pressure drop.

You can really screw up your car if you put in a meter that shifts the transfer function lean, and then put in a chip that makes it lean BUT did not put in the right air meter transfer function.

Does any of this make sense?

jerry

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hey, this makes a lot of sense. My assumption of MAF size equating to HP stems from hearing some corral guys boast about larger throttle bodies showing improvment. I guess I figured that larger diameter = less restrictive intake sytem. But what I interpret you as saying is that is not a significant restriction on these motors.

But now I understand, and that's probaby why you were able to get such good numbers out of tbirds with just your programming and a l-maf. Didn't Derek get some great numbers with just tuning and a diffrent MAF? Is the stock tuning that conservitave? Also, by slightly leaning or changing the curve, wouldn't that improve fuel efficiency?

So you take the transfer function, adjust the curves by using a chip, work some of that jerry magic. Am I on the right track?

also, how exactly do you measure CFM on an air meter? I know how to measure it with a ducted fan, and other fan units.

This all makes me want to move north!!!

Thanks,
Brian

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Well on the t-birds, the stock programing is pretty marginal. It's about as rich as the Mark, and since it's a regular fuel car, it picks up alot using premium.

On the rumors of the throttle body making more power, let's cover that.

If you put a larger throttel body on a car, now, at the same blade angle, you have more opening, hence more air. So, people think that car picks up all this part throttle power since it's so much faster, but what it really is is more air flow, via larger blade, at the same angle/foot movement.

Typically something is flowed on a flow bench with a pressure drop of 28" of water. You contorl this by using a monometer (SP? I am an engineer I cannot spell) with a tube hooked to the inlet and the outlet. You adjust the pressure drop by varying the flow at the outlet end to get the 28" of drop, and then use a flow meter to measure flow. A lot of room for error.

If you go leaner you will pick up fuel economy. This is my second gen calibration for t-birds.

Ideally to get the right tranfer function you have air meter, air box and tubes flowed by some reputable company. If that is not possible, and it rarely is, I shut off the adaptive fuel feature in the EEC, then drive the car around while it's closed loop (running 14.64 A/F ratio and using the O2 sensors to maintain this) and watch the "short term fuel correction". I then adjust the air meter tranfer function to be within about 5% correction. Then you take the car to a chassis dyno, and make a WOT run starting at about 1000 rpm (I can lock your automatic trans in 3rd gear with the converter locked) all they way to peak power plus a few hundred. Then I look at commanded A/F ratio (since it's now richer than 14.64 and open loop) and adjust the air meter transfer function to get the a/f ratio that it is asking for. When you are done, you turn adaptive fuel back on and you are done.

jerry

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I have the 90mm LMAF on my car right now. Jerry burned the chip for it. I'm not impressed with it at all. And Jerry realizes that I don't blame him....I hope...lol. I personally think it was just too big for the stock DOHC. I went with the 90 because I'm planning on installing an S-Trim in a few months and figured it would be the best choice. I think I was wrong and the 80mm would have worked out better. I dynoed the car with it completely stock (silencer and paper filter) and got 225 rwhp and 240 ft tq. After the install of the 90mm LMAF and Jerry's chip I got 222 rwhp an 223 ft tq. The air/fuel was off the scale rich from the point you mashed the gas. This problem can be fixed most likely by leaning it. And hopefully gaining some power. Jerry has the dyno sheets and I'm going to try and lean it out with the EEC Tuner some and see what I can get and send the info and chip to Jerry. If I don't make any head way then I'll have to do the trial and error thing with sending the chip back. I would stay with the 80mm if I were to do it again Brian.

Jerry, I have the GUI Pro now but I can't get it to work with that .dat file you sent me or the one in the GUI. I keep getting incorrect bin file for both bank 1 and 8. I know it isn't the correct file like you told me but shouldn't it still open and let me see something?


I've had some people that are bad mouthing Jerry's chip I have installed cause of the lost power. Hey I asked for a chip that would work with the J-mod, get rid of the speed limiter, have the transfer functions for the 90mm and raise the rpm limit if he thought it was safe. I got all that, just lost some power. Now if the car were on the dyno when the chip was burned, like Jerry explained earlier than that would be a different story I would have expected substantial increase in power. I did expect to gain about 10 rwhp though just from the increased air flow. Jerry will most likely jump in here and explain what he thinks is up though, he's the master. I've only been at this for about a year with the Tuner and it still kicks my butt.

Lonnie

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Jerry, i just found this board yesterday and have been reading some of your posts. Fascinating stuff.

I plan on having you tune my car when i have a chance to make it to one of your dyno sessions.

My question, should i even bother with a mass-air sensor? The most i plan on doing with this car ('97 Mark VIII) is the intake (mass air/cone filter), gears, posi, a 75 shot, and i already have a decent exhaust. I want to get any nitrous or intake modifications done before i have it tuned, obviously. If i don't change the mass air meter, i'll just yank the silencer out of the bumper. So, do i buy it, or save the money and just get the spray sooner?

I hear you saying that the mass air is only worth 3-5 hp on a stock motor. To me, that's hardly worth the cost. But if i put nitrous on it, or do some other bolt ons, will it become worth it to upgrade?

Thanks for sharing your wisdom.

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Jerry I need mine dynoed by you and I have 2 Mustangs for you also here in Dallas...

One stang is a 98 other is a 01

What does cutting out the post and resizing the sample tube do to the MAF?
Please explain in technical terms...

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I'm out of town and I'm stuck on dial up. Give me till the end of this weekend and I'll answer.

jerry

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I'm running an '01 LMAF (90mm) on my BullittBird -with '01 PI-heads and a Bullitt intake. I've had no problems with it at all, but then 'Christine' is Jerry tuned 100% tip-to-tail [even twice! ....LOL]. I don't think there's any measureable diff. in what you'll get w/a 90mm vs. an 80mm at airflow readings that most guys run with NA set-ups and their power levels. Maybe once you add spray and/or start moving the 'Big-Air" #'s like the Lightnings, and blower-boys -the addit. 10mm calibration would reap some justified rewards. I've seen many comparable T-Bird buddies w/the 80mm's put down the same (or slightly better...) numbers as the ones running a 90mm with like-modifications. And as the design and pressure drop characteristics seem identical, except for the 10mm diff. in venturi along with the accompanying A/F tables and transfer function, if your set-up doesn't call for the potentially higher end advantage the 90 offers over the 80 -it becomes a non-issue. As for my reason(s)... well, it's a Ford part regardless (hence known and dependable calibrations and serviceability and troubleshooting) and the 80mm's were (still are...) requiring a core charge whereas the 90's don't. And yeah, maybe there was a sprinkle of that "Big D*" syndrome in there -that we all succomb to once in awhile. I also think any "SOTP" meters vs. actual documented, side-by-side comparisons are very suspect. LOL

So my opinion, based on like-comparisons with various fellow T-Bird friends (DanU, Seabass, JohnnyL, KrisD, Richard McC., BigScott, etc., etc.... ) and even some of my more local T-Bird buds who run them ---is that unless you're putting up the airflow numbers to warrant it, -I see no advantage of the 90mm over the 80mm other than the referenced costing spoke of above Ovbiously, if you are pushing the #'s to justiify it, you'' no doubt peg the 80mm before the 90mm.

Peace,
BullittBird ~MikeV.
P.S. I'm also sure that Joe at CustomChip has the ability (and tech. data) to place 'either' transfer function into your pcm (or via a chip) in lieu of the unavailabilities of Jerry's former Inject_Tech offerings.

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Like I have said before, a Mark 8 already uses an 80mm MAF, but with a full post. The gains people see when changing MAF is from making the car run leaner up top where it's real rich from the factory.

If I'm you, I save the money on the MAF and get the "hose" sooner.

On removing the post, you do the same thing. You force less air through the air meter and that will make the engine run leaner and have more timing. Again, on a stock car this MAY be acceptable, most go too lean and have knock issues.

jerry

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When you remove the post, after doing so I drilled out the sample tubes... I had a few cores to play with so I built a few...

The smaller size drill worked better than the larger size..

Does a larger sample tube force more air over the element thus resulting in a leaner mix and more advance?
If so this explains the problem I encountered with the 98 GT I used the larger tube on it and it started pinging... However we were running a timing adjuster set to 14.5 degrees and moving it back to 12 solved the issue.

I dont think anything can help a 98 Motor... Heads,Cam intake etc just stink!

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Brian,

Here's your answer (one month later). I went 15.3@91mph with just a meter and eec tune. I don't really think the conical filter or 70mm TB had a big role in this. This was done at a decent track, Lapeer (not at Milan) and on street tires.

Super98,

The MAF filiment is going to pick up the extra flow and now instead of "x" counts responding to the proper "y" value in the Xfer function it's going to reference some other value. I think you know what happens from here.

-Derek

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I have a gutted and drilled stock maf in my car right now and it runs pretty well. I know it's not perfect though. I also have a 90mm lightning unit that I'm not using right now. It didn't work with or without the chip. I will be bringing both to the tuning session in Dallas on the 5th. I also have the 160 t-stat and 2001 lightning fine wire plugs in a 12 heat range. My question is is it better to start with the 90mm or the gutted stock MAF for the dyno tune? Or would I be better off getting another stock MAF. I'm not sure if I have drilled the sampling tube to big or not but it seems to be running rich (mileage down) but I did gain some power. Any advise on what I should do before Friday? I'm assuming that Jerry can program around any sampling tube change but would a home made job ever be as accurate as a factory unit? I would also have to agree that Jerry's technical posts are fascinating and make sense. Thank you for all the wonderful info, Jerry.

Boozer
97 Green Mark VIII

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I'd like to use the 90mm MAF. I would put in the 160 'stat and the plugs. If possible, try to get some cold air ducted to the air inlet to reduce the possibility of knocking as much.

jerry

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I already have the plugs and stat in and will bring the 90 with me. I have a heat shield around the MAF but it could probably use a little work to make it seal a little better. I plan on adding a ram to it after I get it properly sealed. Thanks for the help and I will see you on Friday!

Thanks

Boozer
97 Green Mark VIII