Actually it depends on the ECU. Many of the older ECU's do not support enough air flow through the MAF. The maximum values you can populate the table with are below the flow rates your MAF will be seeing at these power levels. It is maxed out long before you reach your power potential. It would be like trying to use 20 lbs of boost on a 2 bar system, the MAP sensor would max out at 15 lbs and you would have no way of telling wither the engine was seeing 16 lbs or 20 lbs of boost.

I guess if you had a tuner that could, solder some new higher capacity ram chips into the ECU, write a completely new operating system, like HP tuners does, for like the 2 bar SD and 3 bar SD operating systems, and calibrate it to a newer high flow MAF like the one on the LS9 or LSA it could probably be done. I don't know any tuners that are capable of that. I would consider that above and beyond of most tuners, that is more like reengineering an engine control system. The SD tunes work so well, I can't really see any need for a MAF. I never noticed any reduction in drivability when I deleted my MAF and went SD. I still use the O2 sensors though, some people do strait open loop. Basically that turns it into an electronic carb, or makes it equivalent to mechanical fuel injection.

 

LS7 MAF in a 4" tube like plenty have done before and a rescale of the tune will handle a hell of a lot more power than 4 psi, no soldering new wizbang processors or RAM required. I would also argue that I don't care what the MAP is seeing, 16 psi vs. 20 psi, as long as the MAF if able to read the extra airflow it will be okay. Theres a reason high hp factory cars as well as high hp cars that companies like Lingenfelter put out kept the MAF. On my old car, I had rescaled the entire tune by 60% and logged 900fwhp with an LS7 MAF in a 4" tube and the car drove like stock.

 

What ECU was this and what operating system? I'd really like to learn how to do this if possible? I'm guessing it must have been a gen 4 or newer PCM? The Older ones I've done like the 212 ecu required deleting the entire MAF function just to have enough memory to store the extended VE table for values above 1 bar, and a boost enrich table. GM never put any more ram in it, than the absolute minimum to run what they put in there for programming. This is also why real time tuning is not available on these ECU's. Deletion of the MAF function, as well as a couple other little used things, is what HP Tuners did in their early 2 bar SD OS, to make room for these required functions for boost, which many of us have used.

Lingenfelter and the factory did exactly what I was saying to get the MAF meter to function, they built either custom electronics in the case of Lingenfelter, or the factory designed a new ECM with more ram and processing power to manage both the SD portion, enhanced up to 3 bar, and the MAF portion for these higher HP applications.

 

A 98 POS OS that everyone said was awful, no custom OS, EFI Live. Greg Banish has a section in his dvd on how to do it, and its really not hard at all, just takes some time to hit all the tables.

 

For the OP, can't believe how long you have been messing with this car. I've probably had 8 cars to your 1. LOL

With your turbo setup I would never/ever run a MAF. Common up here is pump gas and methanol. Open loop speed density tuning is easy and changes per weather altitude if you know what your doing.

 

100% street driven daily driver type of fun car. Roll racer only. When I come home every couple months for my one-month off periods....I have a rental car. So I drive them both.....but I mainly drive my car, my wife uses the rental.

But like I mentioned....my Huron Speed kit piping is made to use a FMIC....the Bell 4.5"....So I would have to get new cold pipes built I guess.

I suppose if the FMIC can only be a PLUS and not a NEGATIVE in any way.....I'll just stay with that plan.


Truth about the Middle East:
I'm in Beirut today....3 night stay. Best place in the Middle East...BY FAR. Dubai is a completely fake city to be honest, its not at all what people think it is from watching TV or seeing ads about it. Its littered with prostitutes on almost every street corner, every bar, lounge and club...they are everywhere. The arrogance of the Emirate's is sickening.....from expecting you to hold doors for them, to tailgating you at 100mph literally 2 inches from your bumper in their Bugatti, Lambo, Rolls or Mercedes....to walking right into you at the mall because they truly expect you to walk around them.
Its a total slave nation, the UAE. The only people you mainly see every day and everywhere you go are Indian, Pakistani and Philipino...and other poor Asian nationals. They do all the work in Dubai and they are treated horribly by everyone......
Its just like Las Vegas....after 2-3 days.....you need to get the hell out of there. Besides a big building, a big mall, an indoor ski slope and riding a camel in the desert........Thats all it is.
The big Palm Island is a failure and its sinking.....people who have homes and apartments there have cracks in their walls and uneven foundations. It will be abandoned one day. The other 3 man-made islands already sunk under the sea......
My flight attendant was hit in her car by an Emirate.....Emirates fault 100% and 20 witnesses watched it happen. My flight attendant is from England. She got the ticket and she had to pay from her insurance company for both cars to get repaired. They always side with the Emirate no matter what. Sometimes in clubs and bars you'll get the arrogant little young ***** Emirates that will tell you they will kill you later in the parking lot.....because they will walk right up and talk to your girlfriend, or my wife in my case, and when you say hey shes with me....they just say I'm not talking to you go away.
My friend flys for the UN....he gets security alert memos all the time like we do. Plain and Simple....the Emirates pay ISIS money to leave them alone and not mess with their planes. ISIS members also get their R&R rest periods in Dubai.......they are ordered not to mess with anyone while there but terrorists are all around and among us. I personally carry one of two weapons every time I go anywhere, just in case. Last year an American teacher was buthcered in a mall bathroom by an ISIS loving Emirate......youtube video of the killer going into the bathroom and killing the lady. They caught 43 ISIS guys trying to cross the border last year too.....never made international news.
There's a tall building catching fire every month here.....no building codes and only untrained Indian/Pakistanis build everything here.
Watch: "Slaves of Dubai" on youtube......thats what these arrogant **** Sheihks do to these hard working people here. Yaxi drivers...10 months of work, EVERY DAY, not a single day off. 12 hours on, 12 hours off. $680.00 usd each month. The 2 straight months they get off they don't get paid.

There's a whole lot more I could tell you......but I'll need an hour.

Go to Beirut.....it is awesome. Why...its mostly Christian Arabs....not Muslim.

With all that said....of course I made friends with a few Muslim Emirates in Dubai. few Iranian defectors, Saudis, Jordanians, etc..... Great people, normal in every way.......they hate the Radical Muslims. And they all love America......I wear my American flag baseball hats and t-shirts...people want them. And not to get political...everyone over here, loves Trump.
If you ever come to Dubai, let me know....we'll party. I'm 48 yrs old and we have a lot of fun. Only way to stay sane while we're here....lol.
.

 

SethU, kingtal0n, ScottyBG,

So how about when I see people putting an additional fuel injector right next to the primary fuel injector...so they can have a Direct Port Nitrous kit.

What if someone used that same set up and sprayed Meth into each runner at that position....? Under 250psi for proper atomization?

OR....did I not yet fully understand ALL this technical data you guys have been posting....which is very cool to read by the way. I took Physics classes and Physics Labs in college for my Aerospace Science degree, but you guys are talking on another level....LOL

.

 

I know...finally bought the turbo kit and everything else associated with it, including the level 4 4L80E.

Just wasn't ever sure if I wanted to sell it and get a GTR or something newer over the years.......I also have an odd career.....back and forth to the Middle East on a rotational schedule, so every time I go home for my time off....its usually 3 weeks to 8 weeks OFF at a time......I do nothing but party and travel.
Between boating, guns, traveling and partying.....I'm a procrastinator...lol

But it'll get done, hopefully my next OFF period at home. Want it to be done right and the best set up for its level.

I'm on the fence about getting the GTR out here in Dubai.........don't tell my wife....

.

 

Port injection for methanol setups isnt new, and yes is very viable. You can get atomising nozzles that work well below 250psi, you can even get them that work at almost no pressure difference ( as you might find in plant growing environments etc )

If you want a lot of good info, there is more on the Aquamist forum.

 

If I'm using full time E85 though.....is Meth complete overkill?

Thats the question....If Meth will not yield me anything significant.....I won't waste the time and money on it.

If I could be safe at 1,000 RWHP and use 93 pump gas.....I would....then I would get the Meth. I'd rather do that than use full time E85......IF 93 pump will do 1,000 RWHP safely.

.

 

http://www.aquamist.co.uk/forum2/vbulletin/

If you're running E85...then yes, meth is probably a waste of time/effort/money unless you live somewhere with extremely high ambient temps and struggle with charge temps because of it

93 will do 1000hp safely if you build the engine to do it, which for most part just means keeping the CR to a sensible level and ensure charge temps are always well under control.

In cases like that, go big, 427, say 9.0:1, good heads, cam etc and the right choice of turbo/turbos etc and there will be no issue at all making the power very safely on pump fuel alone.

 

it might be different for HP tuners or LS engines, but, at least for 0-5V MAF sensors, the curve is parabolic, basically an entry level college algebra equation of the form ax^2+bx+c which i am sure you are familiar with. This formula tells the computer what mass of air is equivalent to what voltage and can be adjusted in the ECU to match any maf, or maf modifications as an arbitrary correlation. for example if you take a maf hotwire from a 2" maf and install it into a 4" maf, it will now read lower voltage at higher flow rates, so you adjust the parabolic equation to give a desired air fuel ratio for those rates. Since we have widebands, we don't need to know how many grams/second (or other mass/flow rate) as it becomes arbitrary, we dial the A/F ratio where desired while staying below 5volt max from the sensor. Many ECU such as power FC make the mathematical relationship readily available to adjust for foreign, never seen before maf sensors.

MAF sensors are ideal for daily drivers. A Maf should always be used if possible in a daily driver with "low power", figure under 450rwhp, in my opinion. Once you pass that point, it may become a nuisance, and an obstruction. The maf hotwire should be protected from foreign substances, like methanol or other corrosive agents. A quality air filter is paramount to any daily driver, street car, and frequently overlooked, under appreciated.

 

The MAF sensors on these cars are not 0-5V, they are constant voltage, and vary the frequency of the signal. There is a maximum frequency that the computer can read, and that is where your limit is, just like hitting 5V on a 0-5 sensor.

 

It is the same thing when some max limit is defined via software. 255hz, 9000mhz, 1volt or 5volts is the limit (or whatever we set "it" to). If you put the maf hotwire into a larger tube, then the limit isn't hit until a greater mass of airflow. The ECU doesn't actually count air molecules or understand that the sensor is a "maf", it just reads from zero to whatever the max is, and that is what we set up in the tube. I could setup an emulator which outputs 0-x hz that coresponds to a TPSvsRPM map ("alpha-N") and use it as a "maf" without actually having a hotwire or map anywhere on the car. The actual values of ingested air, whether map or maf, is always arbitrary, just as map sensors 0psi is different throughout not only rpm range but also engine size (1L vs 6L engines at 0psi) the maf from 0 to whatever the max output is accounted for in the computer's table. Tuner's job is watch the wideband and cause it to fall within some acceptable range.

for example:
take any maf, and measure its flow in mass/time at peak voltage/frequency output. Now, enlarge the tube, and repeat the experiment. the peak voltage/frequency is now the same limit, while the flow in mass/time has increased with tube diameter. You can keep increasing the tube diameter to inifinity; the net result is a loss of resolution, especially at low mass/time flow rates, which is why manufacturers keep the maf sensor reasonably sized, to keep good resolution in places where people drive their cars most frequently (at low speeds) it is important to maintain a reasonable velocity at low flow rates, which means a smaller diameter tube. The parabolic nature of maf output also shows us that maf resolution is best near the early parts of the parabola as it fans out from it's center, closer to where x=0, and less so near the fringe of max output (highest x values) where a small movement of the x-axis results with a large adjustment in the y-axis.

 

Do yourself a favor and ignore Talon, nothing he talks about is LS specific. Anyways, the airflow limit of a maf you can get around by scaling the tune so you never reach the 512g/sec limit hardcoded in the PCM. The frequency of the MAF can be a limiting factor depending on the OS as some have a higher freq range than others. However, you can give yourself a better shot at not hitting the max frequency by using the larger tube with something like an LS7 MAF as it will drop your frequency for a given airflow. I wasn't frequency maxed at 900fwhp like this.

 

My motor is already built and in my car. It's 10.8:1 cr. I can drop it to about 10.2:1 by using LSA heads.

So 1,000 RWHP probably can't happen safely on 92 pump...right?

.

 

Here is the part that people are not actually getting here, there is a maximum value for the MAF defined by the OS. See the screen shot below for example. This is from a tune where the power output of the combo exceeds what the ECU is capable of calculating. The MAF maxes out at 11,250 Hz, see the far right hand cell on the table pulled up. You can vary the amount of airflow this 11,250 HZ equates to by making physical changes to the MAF, porting it boring it out exc. The problem is that no matter what you do the largest value that the computer can associate with it is 4063 lbs/h, see the bottom right hand corner of the "Engine window" This equates to 67.7 lbs per minute of air which will support about 650-700 hp at the crank, or 550-600hp at the tire after drive train losses. This is the limitation people talk of when they say the MAF is maxed out. It is not the physical, or even the electronic limitation of the MAF, it is a software limitation for the operating system. This is not a problem with the Gen IV ecus and the newer ones, because GM upped this limit so they could keep building more power on like the LS9, LSA etc. On our older Gen III, this is a problem. Like I was saying there are ways to work around this, like run 80, lb injectors, and tell the computer they are 60 lb injectors. You can do 2 wrongs to make a right, but I don't expect the average tuner to do this. I expect a good tuner to work within the realms, and defined parameters, of the OS, and make the car run and drive well, be safe, and make good power. I don't really expect them to be able to engineer a modification to the ECU to support the mods, this falls more into the realm of someone like Lingenfelter, not your local tuner with an auto mechanics shop and a dyno. I hope this enlightens someone who may be struggling with using a MAF when they are past the ECU limit.

 

Please read my post. I just explained how to get around this on the GEN 3 stuff. If you want more details PM me.

 

Actually I researched how to do it, after you mentioned it and gave me the lead on it. Honestly I don't like it, or think it is really the right way to do it, it really is doing 2 wrongs to make a right IMO. This is just my personal opinion, I'm not judging anyone that likes it, it is just not how I would do it. I like the deleting the MAF option better. There are pitfalls to either method, we are taking about an ECU not designed to function at the power and airflow levels we are dealing with, and making it work. I just think the pitfalls of using the MAF (without the other functions that come in a good SD OS designed for boost, which has boost enrichment tables etc) are potentially worse than going with an SD OS and going that way. Main thing I don't like is that all fueling in boost is handled by the MAF function only, there is no way to utilize or fine tune the VE table in boost going that way, because it doesn't exist in the OS that has MAF enabled, the VE table stops at 105 kPa in those OS. Also there is no fall back fueling if the MAF were to malfunction. I guess the same thing can happen on a SD car if the MAP fails, but I feel more confident in those. I believe the MAF is more delicate, and in a more vulnerable position on the engine to be damaged or fail.

You will find people on both sides of this argument, but a lot more are on the SD side of it now. One of the reasons, is there are more people using HPTuners than EFI Live on these platforms. The methods used to get around this MAF limitation existed before there were some of the more recent SD OS's available for use. Their availability has drastically reduced the number of people using a MAF meter, on boosted setups. Look at the builds in the Forced Induction setup and see how many are using a MAF? They are hard to find.

 

Everyone has a different definition of "safely". I think all would agree that 1000 RWHP on pump gas can be achieved more safely on 9.0 than on 10.8 cr. BTW, thanks for waxing eloquent on "The truth about the middle east". It was much appreciated.