Importance question

Guero said:

How important is MAF when trying to get the highest HP possible??? Its very important right??

Now did is my real question. What the hell do you do when setting up ur MAF in the tuner. I was reading on it. but to me it seems like there talking in some other language i dont understand jack of it... It pisses me of cuz i read it and read it and i dont understand ****!!!!!!!!!!

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Well i guess its kinda relative , some ppl like to get bigger mafs on a mild engine , i guess its like carbs , what is the point of having a 80mm maf capable of flowing above 1500 cfm, if your engine will only flow at top 700cfm give it or take, leave bigger mafs to blown engines those will require it , otherwise i dont see too much the point , AFAIK i have never know or read anyone that pegged the stock maf on a N/A mild combo, i know not everything its about getting the stock stuff to the limit , but thats just my .02.


Well the maf understanding its not so complicated, its just a sensor with a non linear table of input vs output voltage, you can see the stock maf transfer and get it real easy. analyze other maf tables.

But what i am talking i havent even started my car since i received the tweecer like 4 day ago

Think of it as 2 areas

1. the non WOT

2. WOT

The maf curve or transfer is used diff. depending on the area of use its in.

For #1 it is used with the O2's and calcs. in the eec are made. This is why you can tune most everyday driving around preaty close by using the K's and such.

for #2 (and max power it at WOT), it is VERY important as there is no O2 use so its a calc. with the MAF transfer, Tables, Inj. tables, and Spark tables for the most part. THIS is why its important to have a W/B to make changes to the MAF transfer if your richer or leaner than you are commanding in the Fuel table. The max volts seen really should be around 4.6-4.7 to stay safe...you can run it 4.9 but sometimes funky thing happen and its more of a band aid fix type thing...more for alittle head room but not much more.

The stock maf is good for alot of mild combos. However, if you have a good H/C/I setup you very well might need a bigger meter. Search under grady's posts and yes he got like 29x rwhp with the stocker but HE is sure he picked up a good bit with the bigger MAF and T-body.

I noticed my Maf V. getting preatty high with my fairly mild combo and that is why I went with a 98GT maf...its not as high flowing as the LMAF but flows a good bit better than the stocker.


IN the end it is VERY VERY MUCHO IMPORTANTE to nail down the maftransfer.

its a default type thing as far as setting the min. and max maf v.

put in 0 and re-open the file and it will read a funky number like .0124 or something and the max put in 5 and it will change to something like 4.998 or something.

It goes to the lowest/highest possible number that is the closest.

The best way to see if you need a bigger maf is to Log the Maf v.

For another good thing to log with the tweecer is the actual maf v. you change to WOT. so you know not to mess with that part of the curve if you need to for drivablity as its not part of the drivablity range.

Log

mafv- to see what volts are at what rpm, load, and loop state
rpm- to see what rpm it makes the switch
loop- OL or CL
load- to see were your load is.

If you notice that your MAF v. is getting at say 4.8 and your only at 4,500rpm your going to want to look at a diff. maf. Also if your at say 4.8 and at your max rpm of 6,000 (guessing) you also may want to look at a bigger maf. Now if your at say 4.6 at 6,000 I would say your prob. ok on the maf.

Every car will react diff. and you just need to log and see were your at.

I guess I will throw in my thoughts too!

How about a focus to keep things simple
however
Have you looked at the info on my site

Everything is there you need to understand the basics of mafs.

anyway ... back to the simple

Try to think about airflow being moved through the meter

Lets use two examples

1) Stock Stang
2) Same Stang with a S-Trim

1) Stock Stang has no issues running the oem meter
2) Ever notice how the guys with blowers peg their maf

It is so simple ... more air is moving through the meter because the blower is forcing all that additional air.

btw ... Same thing can happen with a na combo

ANYTIME max maf airflow is exceeded ... NOTHING can be done and you have to go to a maf that can deal with the additional airflow.

Up until this point, we have been talking only about airflow as that is what mafs do ... convert airflow to a voltage in the range of 0 to 5 volts as that is the ONLY range of voltage the pcm can deal with.

Move more air than 5 volts worth ... You've pegged the meter

Now lets move to other topics that comes up when talking about mafs.

1) Injector size.
2) Aftermarket caled mafs such as say ... a ProM for 24's

IMHO, here is where a lot of peeps don't seem to get the jest of the whole maf/inj thing.

Remember ... our focus is simple so I'm gonna ball park things

Our example Stang is now gonna be say something like a h/c/i combo with around 275 rwhp.

This example combo is most likely NOT gonna be moving more air than the oem maf can accurately report to the pcm

HOWEVER

The tiny 19's have now become too small

If you self tune or Pro tune ...........
you could make the oem maf work with the larger 24's

Most peeps don't have that ability so they go for a 24lb caled maf to go along with the larger inj's.

This is the cheat method used by maf manufactures.

ALWAYS remember the whole Cheat thing is based upon the pcm values being unchanged.

You got larger inj's
but
the pcm don't know about it

How the maf manufactures get around this issue is they cheat by telling the pcm less air is flowing through the meter.

If the pcm sees less air is moving ........
Its gonna command a smaller injector pulse width .........
which is so very necessary ..........
Because you now got larger sized injectors.

Here is where Self or Pro tuners do it differently.

They just tell the pcm the truth about inj size and airflow through the maf.

I know ... I know ... a bit long
but
Looks pretty simple ... at least to me it does

I almost forgot

Yes Guero ... a good maf curve is important

You basically have ...............
a portion of the curve that is Closed Loop
and
a portion of the curve that is Open Loop

Each part is setup very differently.

I have given basic details about each on my site.

Did any of it make any sense to you?

Grady

Guero said:

i didn't know you had a site, and yes youve cleared up some stuff

Click to expand...

I have pointed many peeps to the info.

I guess you have not noticed it

Grady

Guero said:

woa ur site is helpful!! I think i gonna buy donverts video tuning. But first i gottta buy a wideband. A 80mm LMAF or a 90LMAF.Which one should i get(Do i need to worry about spray when dealing with the MAF)? What connection would i use to connect it to my car?? Would a 96 plus GT work?

Click to expand...

Glad you found the info to be of some help

I gotta tell you ...............

I don't have any spray knowledge so I defer to others for the info you seek.

I have seen lots of forced combos use the L mafs. I really have not paid much attention to those who use them for na combos.

Seems like Greg has a pretty good idea about their application.

I just did the ProM thing because at the time I switched meters ......
It was a known proven way of getting the job done with the least amount of hassle on my part.

Too Late ........ I'm outta here

Grady