Hackin the MAF

[toddinsb]

Can I have your guys opinion on the hacking of the MAF. I look at a lot of people talking about modifying the MAF and I can't help but think how stupid it is to take info away from the ECU. Am I just an idiot or would it be a better idea to keep the MAF stock (so the ECU actually knows whats going on) and get a standalone or some type of piggyback enginge management.

 

[kpt4321]

It would be helpful if I knew if you had a 1g or a 2g. The following applies ONLY to 1g's:

There are several reasons for hacking the MAF. Understanding them requires that you understand the basics of how the MAF works, if you do not, ask and I can explain it.

First of all, the factory fuel maps are quite rich, I believe somewhere around 10.1:1. That means that, assuming we are using good gas and keeping an eye on things, we have some room to play in terms of leaning the car out. This is not the main reason we hack the MAF, but it is just information that shows why we are able to do so without creating big problems in terms of A/F ratio.

Basicially, all hacking the MAF does is increase the the amount of air that masses through the unmetered sections of the MAF, which changes the true value of th airflow, compared to what the ECU calculates it as.

This basicially solves, or at least temporarily pushes away, two problems.

First, you have fuel cut. When the ECU decides the mass-flow of air is too great, it will cut fuel to the motor for a short period of time. By reducing the Hz signal tha the ECU sees for a certain amount of airflow, we delay fuel cut until a higher airflow level.

Second of all, you have MAF overrun. Once the flow through the MAF reaches a certain point, it will get turbulent, and the MAF will "lose counts" of the air. When this happens, the A/F ratio gets all whacky, and the car stutters and runs very badly. With a stock MAF, this can happen at fairly low boost levels.

Hacking the MAF pushes these problems further away.

...Kyle T.

 

[Bohrn]

yea what he said. You will learn to listen to Kyle if you are here long enough

Plus I will add this. The part that you are hacking is NOT anything electrical, or important really. Its just cast plastic. And you can go very mild to a bit silly. I pick somewhere inbetween, leaning to silly.

I think this http://www.vfaq.com/mods/MAFhack.html is a bit silly and can cause more trouble than it is worth on a daily driven street car.

I did this http://www.roadraceengineering.com/instructions/1gmashacking.htm mine looks just like the last 2 pics.

you can also do an inbetween porting job. Remove lower honeycomb, back out the screw and really clean up any leading edges, smooth out the flat areas to flow better etc. I wish I had taken some pics of mine before I did "Stage 3" hehe, so I could show people. It was actually quite nice

Best of luck.

PS, you can't go nuts with a stock fuel system tho, you need at least a bigger pump(I used a Walbro 255) and rewire. Bigger inj and an safc will be best with the more insane hacking/porting.

But I did get alot better fuel economy when I did this, and passed my emissions tests VERY well.

 

[dunkyfried]

?.... the guy that I bought the car from, didnt know the at the time, but he wasnt honest about anything on the car...so anywhooooo With the fully hacked MAF, I mean nothing in there, could that cause it to run a little crappy... I have change the plugs, wires, fuel filter, timing belt and other belts and still hesitates..... this is at any rpm... If I hold the "go pedal" and hold to any rpm you can hear the car hiccup and the rpms go up or down by about 100-300 rpms...same at idle too I know this sounds ghetto but with the K&N filter, how does it stay attached to the maf... I am using gaf tape right now (I know I know)

thanks guys

 

[Bohrn]

Dunky, if the maf is even moderately ported/hacked it will make your car run lean. If it has a completely stock fuel system, and it is really ported out, it will run very lean. The symptoms you describe are typical lean misses and lean running engine.

I have a walbro 255, stock regulator, and a 10guage fuel pump wire. By most accounts, this combo will make your car run so rich it will hardly idle, spew black smoke, run like crap etc. I have really ported my maf(even more so than the last 2 pics in the RRE sequence) and it was so lean I had to go 30% rich on the SAFC, just to get it to run nicely. Even with this fuel system it was SOOO lean it popped, farted etc.

So this thing really does have an effect on your car.

You should pull that maf and have someone who knows have a look at it. Or you could post pics here for us to see. If its well done, you could sell it and get a stock one. Or you could build your fuel system to match it.

 

[dunkyfried]

holy crap this is two days with two straight answers.... thanks

I will try and get a hold of a digi and take a few tonight...
the only other thing that I have heard that it might be is the ISC but I dont get the huge surge that everyone talks about.... what about one faulty injector..would that do it ????

 

[Bohrn]

ok, sure, send me the pics or post em.

I don't think it is a bad inj, but I could be wrong. ISC doesn't cause misses, it will cause idle surge etc. but yours sounds like an excessivly lean mixture. Do you have a logger?? I'd say your low trim is up past 140%(as lean as the thing reads) I bet you get good mileage don't ya

 

[VASKO[BG]]

My opinion is: Remove only the silencer if u want to hack ur 1G MAF.
The only other think that is also good is slap 2G MAF to ur 1G.
All that crap about hackin ur MAF is not good at all.I did all of that they say there and gess what?I had to go and buy new one after all.Simply the car didnt run as it should be and the RPM were never at one level.

 

[kpt4321]

Removing the siliencer is not hacking the MAF.

I very much support the typical hack-job of removing the lower honeycomb and backing out the screw. Yes, your car will run slightly worse at idle after this. However, I have known people with unhacked MAF's, and it is not good news. I have seen fuel cut and overrun at 14 psi, without boost leaks.....

You can only put a 2g MAS in a car if it has a SAFC to go with it, so it's not a cheap mod by any means.


....Kyle T.

 

[Bohrn]

well, of course you are entitled to your opinion.

But intelligent porting of a 1g maf IS a good thing to do, but you have to match it to the rest of your system.

ALL the good tuning houses do this. RRE even has instructions.

Doing it properly will give you better mileage, more power, less chance at fuel cut, less chance for maf overrun, better throttle response, and even nicer turbo/bov sounds.

I notice no adverse affects from doing it. Admittedly I waited to do the major porting(removal of alot of material from the lower area including the channel for the adj screw and the thick areas on the sides) till I had an safc, but the minor porting was just fine with a stock system.

 

[BLACKDRAGON]

CLUB DSM MEXICO

WWW.CLUBDRAGONES.10.ST

 

[dunkyfried]

ok thanks guys I am gonna try to get a hold of a digi cam, but things have been crazy lately... even if I do figure out the problem, no $ to fix...I hate the way it sputters... oh well what can ya do right ?

 

[peregrine]

my mas has ended up having the lower chamber completely removed. i did it in steps trying to tune it for max power and good idle. i was getting a sputter at 6000 rpms under high (26 psi) boost and couldnt figure it out. now i fully gutted it and it runs like a champ. ill do this until i find something better.

 

[nined2tsi]

If I have a 190lph fuel pump and a maf with no lower honeycomb and screw backed out, would I run rich? That is my dilema now. My car seems to have a boost leak but I think its the maf not hacked enough and Im running rich. What are your guys thoughts?

 

[Bohrn]

nined2tsi, you sure could be rich. You can smooth out the flow more in your maf, but to tell for sure you need to log it.

 

[kpt4321]

Originally posted by nined2tsi
If I have a 190lph fuel pump and a maf with no lower honeycomb and screw backed out, would I run rich? That is my dilema now. My car seems to have a boost leak but I think its the maf not hacked enough and Im running rich. What are your guys thoughts?

That is hacked enough.

If you have a boost leak, that will make you run rich. Fix the boost leak!!!


....Kyle T.