out flowing the maf

[jbamin]

so as in my intro thread i said i was a honda mechanic, and well we don't typically use mafs for anything.. just rely on maps and ad sensors so at what point on the msp do you begin to outflow the maf, and what do you have to do to run the extra cfm.. the turbo i plan to fun flows 61# per min. do i have to somehow switch to speed density?

and help and stats on a stock maf would be very much appreciated
J

 

[low_psi]

Depends on air density. You can max the MAF out on stock boost in winter time. Typically @ 70*F you can run 10-12psi without maxing the MAF out. The best solution is to run a Haltech or Microtech which allow you to convert things to speed density mapping.

 

[jbamin]

is unichip incapable of this?

 

[SleepyMSP]

unichip is a piggypack on the stock ECU and relies on the MAF readings and o2 sensor to modify the signal of the ECU

 

[jbamin]

got it, so haltech here we come then.

 

[jbamin]

whats all involved to convert to speed density on the msp, do i need to look for a certain sensor or...?

 

[ZenProtege]

There is actually a product made that is a programmable MAP that can be used in place of a MAF. To the best of my knowledge nobody has tried it on a MSP yet....I wanted to do it a few years back but couldn't do the whole send my car or critical parts off it out of state for a few weeks so the company could build the MAP.

This company basically said they would put my MAF on a flowbench like machine, run air across the MAF at known rates and record what input voltages the sensor created. Once they charted how the MAF created it's signal in response airflow they could make/program a MAP sensor that performed the same role. The user would even have the ability to fine tune the MAP sensor... The concept seemed simple.

For example... If the MAF produced a 3.6v input signal to the PCM as 40cfm of air passed by it and the pressure created inside the manifold as a result of that 40cfm of airflow was 6psi, then simply program the MAP sensor to have a 3.6v input signal at 6psi. Repeat this process for various flow rates until you have mimicked the MAF's input signals across its' 5v signal scale and translated that into a MAP.

I'm sure there are more variables then I have described but this was the gist of what I took from my conversation with the guys who made the product. I'm looking for a link to the products website. I hope this makes sense to you guys and maybe shines light on alternative to relocating the maf or going to a standalone pcm.

 

[jbamin]

hmm that sounds very interesting.. yeah if you could find a link that would be outstanding

 

[Signature Sound]

yes please. i am totally interested in this too. the thread i started for this is going no where.

 

[tcz]

I do have the same issue on the MAF sensor through reflashing the stock ECU, AFR is lean at WOT. Yes, if I use a piggyback such as AEM or Haltec which using speed density, everything is okay.

I compared the stock ECU maps with Mazda 3 MPS, the parameter of the MAF/airflow is different. I suppose the MAF of M3 MSP is a high-flow sensor. Have anyone tried to replace the MAF sensor by MPS's?

PS: we don't have the MPS in our country, no way to do the testing.

 

[jbamin]

aem or haltech is a standalone not a piggyback

 

[tcz]

aem or haltech is a standalone not a piggyback

you may check with their products.

 

[jamesk]

There is no reason for you not to work your away around the maf sensor to avoid maxing out the maf sensor (fuel cut). When getting fuel cut or a cel for high voltages, you can lower the increments in a fuel map to eliminate the probabilities of that happening. If there is not enough room to play with, then bigger injectors, higher fuel pressure would allow more room for the user to adjust the map accordingly.

Also a cheap solution, but I personally do not like are fuel cut defenders. They trick the maf sensor into thinking there is a certain amount of air coming in when in reality there is a lot more. It is pretty much a resistor hooked up to the voltage side of the maf sensor.

 

[tcz]

There is no reason for you not to work your away around the maf sensor to avoid maxing out the maf sensor (fuel cut). When getting fuel cut or a cel for high voltages, you can lower the increments in a fuel map to eliminate the probabilities of that happening. If there is not enough room to play with, then bigger injectors, higher fuel pressure would allow more room for the user to adjust the map accordingly.

Also a cheap solution, but I personally do not like are fuel cut defenders. They trick the maf sensor into thinking there is a certain amount of air coming in when in reality there is a lot more. It is pretty much a resistor hooked up to the voltage side of the maf sensor.

Yes, the resistor is good idea. But if I can control the 2D map of MAF is much better to get the commanded AFR. I'm going to install Subaru STI MAF on my sedan for testing.

 

[Signature Sound]

i am totally MAF free now. with the absence of all but one stock sensor, there is nothing to control the idle air control valve. i would say its the only reason to keep the MAF. if you can control the external BAC from haltech, should be worth the extra couple bucks. the ability to have a really nice intake is priceless.