Stock MAF Relocation?

[XiKeiyaZI]

So....I was just reading through some things about venting and whatnot, and about MAF relocating... and I have a few unanswered Questions

1 : Venting Stock is bad. Bad because the MAF meters air, and without Recirc, the metered Air is lost, so you end up with a bad A/F Mix.
2 : The Only way to Vent is to meter after the BOV.
3 : The One way to achieve this is to setup a MAF-T and such...

Could you simply not remove the MAF, make a custom can for it using the existing piece, run whatever intake setup you'd like to the turbo.. and put the custom MAF can AFTER the BOV? Of course that would put the MAF between the IC and the TB...So it'd basically get a correct reading on the amount of air is going to reach the engine.

Am I wrong? Has it been tested? Cause if not.. I'm doing this when I get home today just to see if I can.

 

[gst_man]

You know, I have sort of thought about this as well. But IMO it really doesn't seem worth the effort just to have a venting BOV.

 

[ramsack]

there are 2 types of karman-vortex mas, ones that can be under pressure and measure mass correctly, and ones that can only be in atmospheric pressure and measure correctly. ours is the kind that cannot be pressurized and measure correctly because ours uses ultrasonic transducers to hear the vibrations of air that are produced. the mas that can read under pressure usually use some kind of optical design that bounces off a mirror that senses the vibrations. kind of like if you put a mirror on a speaker and bounce a laser pointer off it, there will be a cool light show. you can use a gm mas in blow-through, but i have heard they are pretty inconsistent, although some people have had good results. i would just go speed density if you need the BOV sound.

 

[jrohner]

I remember seeing on here that someone supposedly tried it and it didn't work. I don't know for myself because I haven't tried it and never will.

What's the advantage of venting your BOV?

 

[ramsack]

What's the advantage of venting your BOV?

none whatsoever! i would save the pieces being removed to do so because the sound WILL get old.

 

[killer_eclipse]

from my understanding the stock maf cant work under boost... IMO i dont think it will work cause of the design of them. but on the same note the gm mas is not designed to be run under boost hence why alot of people have problems with wandering tunes. Anyways back to the subject at hand i highly doubt it will work.

 

[gst_man]

Yeah, I don't see it being worth it.

 

[delta448]

Shame shame for not searching. This topic is well covered.

The barometric pressure sensor in the DSM Karmen vortex MAS will not read much positive pressure, it was only designed to read pressures around normal atmospheric values. It is not like a MAP sensor in a speed density system, and it can not compensate the signal for any large increases in air mass per volume (density) correctly, such as positive boost pressures greater than 14.7psi.

 

[XiKeiyaZI]

Hrm. See, I didn't know about the pressurized part of the MAF. It was just a thought. Not that I completely am head-over-heels about the woosh noise I'd gain, but I always like experimenting with things to see if there are alternatives to having it work correctly without paying $4000. Hahah.

So If that's the case, then the Stock MAF Won't work if the air is pressurized.

 

[ramsack]

how does getting rid of the stock mas cost $4000? did anyone read my post jeez? nothing to do with the baro sensor. the baro sensor is used for a fraction of a second before the car is even cranked to determine the atmospheric pressure. other than that it cannot be constantly used because it will be under slight vacuum from the intake air constantly acting on it. the mas cannot read under pressure because pressure changes the way sound waves act, and our mas uses ultrasonic sensors to detect air vibrations!

http://en.wikipedia.org/wiki/Mass_airflow_sensor#K.C3.A1rm.C3.A1n_vortex_sensor

 

[XiKeiyaZI]

how does getting rid of the stock mas cost $4000? did anyone read my post jeez? nothing to do with the baro sensor. the baro sensor is used for a fraction of a second before the car is even cranked to determine the atmospheric pressure. other than that it cannot be constantly used because it will be under slight vacuum from the intake air constantly acting on it. the mas cannot read under pressure because pressure changes the way sound waves act, and our mas uses ultrasonic sensors to detect air vibrations!

Mass flow sensor - Wikipedia, the free encyclopedia

=/ Don't cause me to get unruley..

My $4000 comment was pure sarcasm. Apparently your ability to recognize these types of comments has dwindled to nothing... not a safe investment when dealing with other people.

Secondly, EDIT

So I was just able to decipher where and at who you were directing your post towards. I retract my Mentrating Female Statement. You should use quotes more often to seperate your statements.

 

[ramsack]

sarcasm can't be transmitted over text. dsmlink is a good, inexpensive way to get rid of the mas, or megasquirt. i wasn't going ballistic over your comment, i was going ballistic over the comment someone else made of the baro sensor.

You should use quotes more often to seperate your statements.

yea i'm just lazy and i dunno how to do multiple quotes, so i usually don't end up going them at all for multiples.

 

[delta448]

our mas uses ultrasonic sensors to detect air vibrations!

In 1991, Mitsubishi changed to a redesigned
Karman-Vortex sensor with an eight-pin connector
that replaces the ultrasonic generator with a
pressure sensor that measures fluctuations in air
pressure directly

http://www.wellsmfgcorp.com/pdf/Counterpoint3_3.pdf

On page 3, under "Mitsubishi Applications".

 

[ramsack]

well IMO that document is dead wrong. look at the 1g technical information manual and go to 14-15. it clearly shows that our maf is still ultrasonic.

EDIT: the manual is for a '90 that i'm getting the info, but any MAF i've ever seen on a turbo 1g is an 8-pin and looking inside there are 2 ultrasonic devices. maybe they waited until the 2g to roll out the changes.

 

[delta448]

Are you using the 1990 manual? I have that one too, and I see what you're talking about. I'm not certain about the document I linked above, but it did say 1991 and up. I doubt a visual inspection would show any differences that may or may not exist between a 90 and 91+ MAS.

 

[ramsack]

i think it's a weird subject. 1gs are 8-pin, and are indeed ultrasonic because you can see 2 of them inside of the mafs. that document says the 8-pin are the pressure sensor type, but ultrasonic transducers are easy to differentiate from a pressure sensor.

 

[delta448]

I'm going to assume you're right on this one.

The sensor signal is self processed within the sensor and conditioned for direct interpretation by the ECU, so I imagine that even if the sensors were different, there would be no incompatibility between years. I'm sure there are guys running a 2G MAS on a '90 DSM too.

I suppose that this is all a fairly moot point to haggle over when the sensor frame and internal components would be likely to fail quickly under the continued high pressure and temperatures that even a well intercooled turbo puts out.

I know others have tried a stock MAS in blow-through in the past, but little is mentioned of how successful they were, which kinda leads me to believe they weren't.

 

[ramsack]

Yea i couldn't imagine it holding up too well to heat and pressure. The 2g MAS is different though, it can handle and measure more airflow, so to swap to a 1g would need something to tune it with. This might be related to maybe not being ultrasonic anymore or other design changes, I really can't say.

 

[XiKeiyaZI]

All very very interesting information.

Hmmm....I would say " lemme see what I can come up with " ... but I feel this one is best left alone.

I don't have the proper tools/programs/management units to play Russian Roulette with my engine.

 

[mathewdylang]

sarcasm can't be transmitted over text. dsmlink is a good, inexpensive way to get rid of the mas, or megasquirt. i wasn't going ballistic over your comment, i was going ballistic over the comment someone else made of the baro sensor.

so if i get DSM link i can get rid of the MAF sensor? mine is bad anyway and i have it unhooked as of right now. that would save me a lot of trouble and i can use the VTA BOV a buddy just gave me since mine was welded on by the idiot that owned it before me. how much is DSM link?

 

[pwner]

I actually tried relocating the stock, and a 2g maf, a couple of years ago when I bought my first DSM. The factory one ran like balls when it did run, so I considered that a complete failure. The 2g maf worked great.... until anything over 7 psi, then goodbye plastic sensor housing.