TrinaBabe

iTrader: (3)

Oh... and I am quite sure the reason my car ran so bad with the stock MAF is because of my intake manifold. I could be wrong but thats my guess because that was the start of it. It ran into the problem where it couldnt catch the idle when I let off the gas ubruptly

TrinaBabe

iTrader: (3)

Oh and the stock MAP sensor I think is just used to find the bara pressure at startup to calibrate the MAF. Mine was hanging in the engine bay and my car still sorta ran with the MAF unplugged It took me three blocks to decide to check it out and low and behold I forgot to plug the MAF back in I assume the car has a failsafe map where it will simply fuel the car based on things like TPS or something.. not sure how it does it but it does without either the map or maf.

Ted B

iTrader: (6)

A MAF system does compensate to a large degree (been there, done that many times) where a speed density system cannot compensate at all. Furthermore, newer 'smart' systems will run the exact same desired A/F regardless of what changes one makes that affects VE.


It's very simple: A MAF system can do everything a speed density system can do AND more, and it does it instantly, more accurately, and requires less user input. It adapts on the fly to maintain the desired performance and efficiency characteristics over years of use despite changing ambient and mechanical conditions, and runs more efficiently, with fewer emissions and with better long-term wear characteristics. And it does all this with no drawbacks aside from the necessity of an additional sensor (MAF).

Those who ARE engineers purposely developed the MAF system as an evolution to the old speed density methodology. This is why it is used in everything from daily beaters to modern 400-500+hp supercars and exotics, and it isn't going away.



The program contains a default 'limp home' mode that will run the car with a minimum of sensory input well enough to get where it needs to be should something catastrophic occur.

TrinaBabe

iTrader: (3)

I am not trying to bash the MAF Sorry if thats what it seemed like.... I am just trying to defend the fact that MAP cars do run perfectly fine. New systems can also use MAP, MAF or any other new way to keep the AFRs where they need to be. That just needs two inputs, AFR and RPM. If you want it to be more technical then add a boost sensor and a TPS sensor and wala, You have auto AFR based on Boost, TPS, and RPM. You dont really need any airflow for that The driveability is what you need the airflow for and MAP cars have perfectly fine driveability.

So yes, the MAF is not a BAD thing, it is great. But in our cases, you can go just fine without one and you do gain certain likeable traits when removing it and dont give up anything.

SaabTuner

Not just your manifold. Your entire induction system affects the lean-tip-in. Even once the air reaches your intake ports, the low pressure signal may still not have reached the MAF sensor. Some cars try to avoid this by using a similar distance or volume from the throttle body to the intake ports and MAF sensor. That way, the amount of time it takes to fill the intake manifold is about the same as the time it takes the low pressure signal to reach the MAF.

Fortunately, the airflow does eventually stabilize. But, the faster you are accellerating, the longer it takes. Which might also contribute to running slightly leaner at lower speeds.

Ted B

iTrader: (6)

The only thing worthy of bashing is ignorance.

They do if programmed accurately. The difference is that with speed density, any change in VE compromises driveability to some degree, while it tends to remain constant with a MAF system. This is but one reason why your car comes with a MAF system.

BTW, 'MAP' is a only sensor, speed density is a methodology.


Wrong. You DO give up a substantial amount of adaptive ability, which is one reason why modern cars are almost all MAF equipped. Repeating myself again, a MAF system can do anything a speed density system can do, plus things a speed density cannot do. This has nothing to do with the logging capabilities of any individual system (i.e. 'a few likeable traits'), which are purely up to the manufacturer and have nothing to do with tuning methodology.

Ted B

iTrader: (6)

The systems I've used assumed the distance between MAF and TB to be a constant. Minor changes seemed insignificant, but doing something like mounting the MAF just ahead of the TB was a no-no.

I never witnessed any A/F fluctuations related to acceleration, so evidently the volume of air between the MAF and TB was relatively insignificant during WOT operation.

TrinaBabe

iTrader: (3)

ok well this is just stupid. You obviously will not stray from your idea. This is the SIMPLE fact... a MAF will be overrun very easily if not calibrated for the cars airflow. The MAF does not compensate for anything we care about... yes for stock vehicle wear Im sure it is great at making sure it still measures well but for performance parts it does not work well. I havent met anyone using speed density (And yes i know the difference) that needed to retune thier car because they changed intakes.... do a search on it for the MAF and you will quite obviously see they have problems with it. Now what kinda of adaptive learning does the maf do anyways? If I put cams in my car I need to retune it anyways... so who really cares what the MAF thinks about them? You are YET to give me ONE reason in our cases why a MAF is better. I havent seen anyone suck 40psi through our MAF and considering I have seen them get destroyed by doing this... my guess is they cant take it. I have also seen MAFs get damaged because of oil from an air filter started to block thier sensors.... Never seen a problem with a Kavlico sensor get oil on it and its junk. Come on... give it up. You may be an engineer but this conversation is about for our cars and for our uses. The MAF gives us NOTHING but does take away from a few things (Intake plumbing, VTA, vibration problems, high boost, skipping airflow because it got over run, physical damage, etc...).

The MAF does nothing helpful for our cars. Not a thing. It does not 'adapt' to crap.... it needs to be calibrated for a specific airflow... it can be overrun extremely easily.

And I find it even more interesting to read that you are yet to find a good thing about the MAF aside from some.... questionable remarks like it can adapt, or, it is why all cars up to supercars use one. Every MAF is designed for a specific application.. considering most people want to modify thier car, the MAF becomes farther and farther away from what it was designed for.... so to sum it up once again:

What exactly are the benifits from a MAF in our specific case? Not because supercars use on or it adapts... if you need to retune a speed density car because of a mod, you need to for a MAF driven car as well.

Here are some of the huge reasons why speed density is better for us:

Will not be overrun
Will not ever skip counts
Much less fragile
No need to worry about getting home if a coupler breaks
No need to worry about VTA (Tial is usually considered the best BOV and a MAF ran car cant use it)
No worrying about retuning because of an intake
No problems working accurately when next to a loud car/noise
Will not have any problems running any amount of boost


So... where is the benifit list for the MAF... it obviously cant 'adapt' to any modifications to our cars and if it can, a speed density conversion would just as well. Sorry if you dont agree but thats the truth.... you could do more with a speed density car without retuning (VTA, Intake plumbing, IC). It is obvious if a speed density car needs to be retuned from a part even if it ran a MAF it would need to be retuned as well.

The MAF is more accurate granted... but what does that resolution do for us... absolutely nothing. I would rather have accuracy at 25-40psi than a whole bunch at 0-5psi. And more about the accuracy, the farther away from its ideal range the more distorted the wave becomes... therefore, it is technically only more accurate in certain ranges whereas the speed density car is always just as accurate.

So... you keep saying this great adapability it has... well what EXACTLY can it adapt to? Certainly not intakes... so what can I change on my car that I would need to worry about retuning a speed density car but could do with no problems with a MAF ran car? Good luck with that one....

Ted B

iTrader: (6)

That's why like choosing cams, turbo, exhaust, etc., it's up to you to have enough sense to pick one that will handle the anticipated airflow. And FWIW, the EVO MAF hasn't stopped anyone from making well over 500whp, so it's a moot point up through at least that level.

And as for a MAF system 'doesn't adapt to crap', that's easy to say when one doesn't know crap about engine management systems and how they really work.

Perhaps that's because I was reprogramming both speed density and mass air systems back when you were still playing with your G.I. Joe? The answers to your questions have been posted above, multiple times. You're obviously still puzzled, so consider one of several decent books on the subject (e.g. Hartman) for a better understanding of how things really work instead of the way you dreamed it.

And BTW, a MAF does indeed work with aftermarket intakes, but there is this concept that must be considered called 'laminar flow', and . . . well . . . shoot, I'm tired of writing, so you can go look it up.

TrinaBabe

iTrader: (3)

OK and since now I am on my kick... from an engineering point its quite obvious that a MAF is not the best way to measure the airflow. If you didnt know, back in the day Renault had a motor that was a 1.5liter, turbocharged at 60+ psi producing 1500hp and revving well past 12k. Ran it during the day, night, rain or sun. It didnt have a MAF and seemed to work ok

Now take today as an example. If F1 teams can spend well over $100,000 usd on a steering wheel wouldnt they probably make a maf that would work for thier cars... they are by far the best automotive engineers in the world, bar none. With a near unlimited supply of cash and the best engineers in the world, they could not make a MAF work better... Most people dont care about tuning thier cars to run well. Once tuned it is plain as day obvious as to why a speed density car is superior to a maf. Sorry once again but the truth is the truth. F1's are the best automotive engineering pieces of machinery and they do not use a MAF. The MAF from an engineering standpoint is better for purely measuring airflow at a certain flowrate... the problem lies when you start to get away from that point they become more and more worthless.. since you cant make it accurate at extremely low airflow (idle) and still be accurate at 30psi it seems obvious it will not work with most Evo owners as well as speed density. I figured since you wanted to throw in the supercar bs that this would help you out. The REAL supercars of the world DONT use a MAF, never have and never will.

I suppose I could also ask the simple question.... do you know of a MAF that can handle what I need without making the car less powerful. I need to be able to drive the car anywhere from -10 to 120 degrees ambient temps. I need to be able to daily drive the car at -12psi to 40+ psi. Doesnt sound like too much to ask... I would also like to make sure I do not LOSE any power by using a MAF so it must not be a restriction. Show me the MAF that can handle this and not lose any power at the 550+ hp levels. The MAF is an easier solution, not at all a better solution.

TrinaBabe

iTrader: (3)

Find me the MAF I need and Id be happy to use it.

And no, you have not ONCE explained why a MAF is better... you explained they are used in your idea of a supercar (Many of which, in fact almost all, are less powerful than many of the Evos around). You explained they can adapt.... but never explained to what they can adapt to You claim they are more accurate, which I completely agree with... the problem is thier accuracy range is very limited.

I think it is incredibly great how I can explain very easily certain points that make a speed density car better and you cant find one real reason for a MAF.

TrinaBabe

iTrader: (3)

Some other interesting points... your now saying that when I redo things in my car like cams, turbo, etc... I also NEED to change the MAF for the car to function properly... never heard of anyone needing to change part of a speed density system because of thier cams or turbo Your right... that adapted WELL. LOL.

But since I havent been reprogramming these things for years I guess that explains my complete ignorance on how adaptive your MAF system is (Needing to change it because of cams... thats VERY adaptive). And since I need to do research about laminar flow to make it function properly... your right... IT adapted well didnt it? Man... the more you post the better it helps my case. The MAF can not adapt to crap.

I also like how I need to actually find a MAF that works for my car... instead of using speed density and never changing it whether I am running a 14b mitsu turbo or the GT42r. Man that system sounds much better at adapting

Glad I could get a real engineer to help me show the light on how great a MAF is. All I need to do is a bunch of research on laminar flow to make sure my intake works properly with the MAF. I also need to make sure I get the corresponding maf to the cars tune for the day... race day I use one MAF and daily driving another one. Or god forbid I change a part like a turbo or intake manifold down the road... then I will need some more MAFs to make sure they can all adapt properly.

Ted B

iTrader: (6)

F1 cars are race cars. EVOs are street cars. The two are VERY different applications. Now what part of that do you not understand?


Really? Well, if you ever lift a finger long enough to hunt down a MAF transfer function, then you'll quickly see why you're wrong. The fact of the matter is an MAF accurately measures the volume of airflow from idle to its practical limit.


You mean like the one Ford uses in the GT40 for example? How about the ones used by Porsche? Do I really need to go on? Is it really so surprising that MAF systems represent the current state-of-the-art for modern automakers?


How about 700+whp?

From: http://www.kennebell.net/accessories...braCoolAir.htm

"The Kenne Bell 12" filter will handle 700RWHP with "0" restriction as will the Ford 90mm meter. "

Been there, done that, seen it, tuned it.

Ted B

iTrader: (6)

Here is a very good article for you to read:

http://www.carcraft.com/techarticles/24549/

TrinaBabe

iTrader: (3)

By saying REAL supercars I meant the F1 cars... not the wonderful Ford GT which is less powerful than my car 550 HP at the crank isnt exactly a marvelous feat.

And this is the quote from thier site which is good to explain how "adaptive" it really is:

"Never, never locate an exposed air filter in the engine compartment where the temperature can be 150° hotter (+10°=1%HP loss) and result in up to 50HP loss! We figured out a way to securely mount and protect it in the fenderwell where it's surrounded by cool air. And this is the only area large enough to accept the required 12" filter. The other major problem avoided with a fenderwell location is "fan wash" (fan air disrupting laminar air flow into the meter). Why do you think they put those little metal "shields" on the aftermarket MAF/"exposed" filters? "

I know speed density cars you could have the intake faced at the damned fan if you felt like it... guess what... it would work flawlessly. VERY adaptive system you located.

I also HIGHLY doubt this MAF will handle 40+psi... here is another GREAT quote from thier site:

"Note: At high air flow, meters are very sensitive, particularly with larger than stock injectors."

Now... you think it might have a SLIGHT problem shoving 40psi at it I do.

And.. is it surprising to know that the current state-of-the-art moden automakers DONT use the MAF.... perhaps you missed to whole RACECAR point... most of these daily driver cars are making racecar power levels. Not sure where you draw the line of daily driver, supercar and racecar. So which is my POS? Its definately not a supercar, I drive it daily but make more power than almost all of the supercars. I also race it. So perhaps mine is all of them at once????

And Im not sure if you finally gave up or what but I am STILL waiting for a list of the benifits from the MAF I found lots of problems but nothing gained.....