MAF table

[weeee_6]

Anyone got a table showing the actual flow grams/sec vs. the output of the stock 86-87 MAF? Is it a frequency or a voltage?

Thanks

Bob

 

[bruce]

Originally posted by rsmith
Anyone got a table showing the actual flow grams/sec vs. the output of the stock 86-87 MAF? Is it a frequency or a voltage?

Frequency.
ranges from 30 to 130 Hz.
Takes building an ecm bench to run all the numbers.
An accurate freq counter on the input end and watching a Direct Scan will do all the converting for ya.

 

[weeee_6]

Thanks Bruce. I actually found part of the info I needed by getting into the ECM tables. I also found the 30 to 150 Hz range in the Trouble codes section on gnttype.org. Never fails, after hours of searching, I find the answer immediately after posting the question, but I have a couple more.... How does the "count" in the MAF table relate to the frequency of the output? It appears to be about .1Hz Does that sound close? Why is there 6 MAF tables? Why do they max out (255 gm/sec) where they do (count 1472)? Sensor or ECM maxing out? Sorry for all the questions, I am a newbie, with an EEET background, and am considering building a SIMPLE MAF X-lator. I plan on doing my tuning within the ECM and don't need all the functionality (or the expense) (or the ugly box under my hood) of what is currently available.

Thanks

Bob

P.S. What MAF are you all using (LT1, LS1, Impala SS) and why? Is the size the biggest factor?

 

[bruce]

Originally posted by rsmith
How does the "count" in the MAF table relate to the frequency of the output? It appears to be about .1Hz Does that sound close?


As I recall it's not linear.


Why is there 6 MAF tables?


Better yet, why do they only use 5.
the early code just seems to be a bunch of patches laced together.


Why do they max out (255 gm/sec) where they do (count 1472)?


gm/sec is just a reference, once you change as little as an air filter the cal is byebye. It sort of works out, but you'll go nuts trying to make real sense of it, IMO.


Sensor or ECM maxing out?


Code is the first limit.
Some claim the MAF's got internal problems and that they can creep up on things.


Sorry for all the questions, I am a newbie, with an EEET background, and am considering building a SIMPLE MAF X-lator.


For the time and effort, you're way ahead to just get a Translator, and spend your time during other things.


I plan on doing my tuning within the ECM and don't need all the functionality (or the expense) (or the ugly box under my hood) of what is currently available.


Then a simple freq converter will get you in the nighbor hood, but figure on ALOT, make that an INCREDIBLE AMOUNT of time with a WB to get things right. BTDT. Maybe you know some tricks that you think will work, but I've gone thru and done a full recal on a MAF, and it's time consuming. Buy some chips, and you see very few if any guys that go thru and correct the MAF tables.


P.S. What MAF are you all using (LT1, LS1, Impala SS) and why? Is the size the biggest factor?


It's about resolution.
I got the best results with a 3.5 sensor in a 3 housing, with no airfoil, and going blowthru.

I've since written my own code, and now have a MAP system.

Answers hidden in the above...........

 

[TurboDave]

Easiest answer as to why they're topped out at 255 is bacause that's the largest numberical value our ECM's can recognize.

255 (decimal) is FF(hex), the largest value available in our "old" ECM's.