As a side note, we are using a "mass" output directly to Antilag's (warren) ecu now. we have the baro and IAT sensors at a fixed value, and i have the baro and iat compensation tables zero'ed out in the binary. in other words I took out the ecu's ability to calculate mass from the volumetric input from the maf and I am now feeding mass directly to it. so far it it working flawlessly I will keep everyone updated.

 

Warren said you had some questions about his hz readings. Remember that you have a 30C cal on your maf, warren is using a 42 so for example if you see 1000hz at 2000 KG/hr
he will have 1000hz at 2800 (42/30)*2000KG/HR=2800KG/HR

Hope this makes more sense.

 

Yeah I figured mine would read differently than his.

I really do need the new electronics though, the analog electronics are beginning to give me some trouble lately.

 

Ok jack, The best equation I can find for the stock maf is

Y^.5=.73157811+.81831828X^.5


Y= Mass flow (KG/HR)

X= Maf reading (HZ)

Hopefully this will help you with some of maf playing

 

ok if you really want to get in to it and be exact, this equation fits the stock maf +or- 1%

Y=(a+cx+ex^2+gx^3+ix^4)/(1+bx+dx^2+fx^3+hx^4)

a=-1.1103399
b=-0.17779461
c=537.11513
d=-0.30302299
e=194.60566
f=0.056367154
g=-503.71117
h=0.030329681
i=163.1643

Y is mass flow in KG/HR

X is maf reading in KHZ not hz.

 

That definitely helps.. Only my electronics are becoming really flakey lately, hopefully I can replace the old analog hardware soon.. I can't even really drive the car right now.

 

That formula helps alot, especially with the logging tools I have which can calculate this stuff.

 

If you think about it, If someone has a dyno pull with a data log, you can use this equation compare a HZ reading to hp at different rpm and find out HP per KG/hr of air. This should tell you general VE and all kinds of other useful stuff

 

one more thing that equation is what I got at 1.1835 kg/m3 air density.. these values would change with different air temp ,hum. and baro.

Unless you're running a hot wire maf

So I don't lose anyone on this..


take the hp and hz reading 7000 rpm use the above equation to convert the hz to mass flow at 1.1835 kg/m3 air density. example.... 2400HZ ...bla bla bla math= 1432 kg/hr. re figure that number using the air density the day of the dyno pull, and now you have how much horsepower a general evo engine makes with every kg/hr of air so on later days you can look at your log, see 2800HZ and know you were making about X horsepower.

 

BTW, did you get my PM? My Maf is fine hot wire and all, the electronics, well, you know my plight..

 

I just read your p.m. and replied.

 

2800 HZ Nick ? yeah right what were we seeing with my car.. up top no more than 1800HZ .. now wasn't there some general value that the cobra guys were using that if you pegged the meter at right around 5 volts, on a 42 curve you were making right around 600 at the crank ? true or not... now get back to work and finish my file
Jack..the evo went 13.52 @ 117 first pass ever in the car with a 2.67 sixty foot (yeah I was having a cup of tea before I launched )

 

I'm not technically inclined, but I'm trying to figure out how this affects my car...

 

Because the stock maf is a HUGE restriction and starts losing count at around 2850 HZ.

 

You might want to clarify, The MAF can flow quite a bit of air, but it begins to lose its accuracy at over 2600hz (which was what I saw in my tests) and you saw around 2800.. So no matter how restrictive/unrestrictive it may be, its useless in measuring flow over a certain point. I think thats what we all we're trying to say..

My meter itself reads nowhere near 5v at 23psi... but I don't have the ability to log that particular signal so I have nothing other than what I was reading with a multimeter..