a MAF too small

[CSH-HQ]

>
>Regarding the minimum flow rates, you do need to make sure you are not at
>the bottom of the scale at warmed up idle but we have used this technique
>(the two MAF method) as have other companies when nothing else would work

Nothing else meaning didn't try MAP?.

>(I have even seen a GM development vehicle with two MAFs but only one
>connected but I was told they had also doubled the MAF g/s to frequency
>table in the calibration - in the example described with the 1986 to 1989
>that is not possible the table is already at the maximum of 255 g/s and
>with the voltage type MAF the range is fixed 0 to 5 volts unlike the
>frequency type that often have much more range than the vehicle ever uses).

????, not in the case of the GNs..
>
>On modified engines you are usually idling at a higher g/s than stock
>(especially if you have a larger engine and a higher than stock idle speed)
>so you can usually half the scale at still not have gone below the bottom
>of the table. One thing to do on voltage based systems would be to check
>your warmed up idle voltage from the MAF - stock is 0.5 to 0.7 volts. If
>you are higher than this on a modified engine then you have some room left
>in the table. Keep in mind a lot of the calibrations are designed for very
>low idle speeds (525 rpm in some cases).

But, double?, I just haven't seen it.  Mybe if idling at 1K, but who wants 
that?.
>
>Finding a larger (higher flow range - not restriction) 0 to 5 Vdc Bosch
>type meter has not been easy either. It seems that in those cases where
>higher ranges were needed, some of the OEMs also went to two MAFs (Nissan
>Skyline, BMW M5, Mercedes V12 etc...).
>
>So who feels like making an analog averaging circuit for two 0 to 5 Vdc
>signals? You could leave the burn off circuit attached to just one MAF or
>make it operate both MAFs if you wanted.  8-)  (What would the time delay
>in such a circuit be?)

I still say a $50 MAP is the better answer to the $300 Hi Flow MAFs, just 
wish we had more versions of code to run 2-3 bar maps.
For the $300 MAF, might as well run a Haltech, and then be able to have full 
time Baro calibration map
Bruce
>
>
>
>Jason
>
>
>At 02:24 PM 7/23/99 -0500, you wrote:
>>I'd look real close at what the min rate the MAF will accurately sense 
>>before, running out and buying injectors to try this.
>>  I thought the Hacs showed a min, and max frquency?.
>>Bruce
>>
>>
>>
>>
>>>At 01:18 AM 7/22/99 -0800, you wrote:
>>>>Isn't the problem not that your maxing the MAF sensor, but that you are
>>>>maxing the computers internal airflow variable at 255 g/s?  It's a
>>>>frequency MAF, right?
>>>>
>>>
>>>The 1986 to 1989 Corvette, Camaro and Firebird use a Bosch MAF sensor that
>>>is a 0 to 5 Vdc sensor not a frequency type sensor (like that used on the
>>>1994 and newer Corvette, Camaro and Firebird).
>>>
>>>One thing you can try is using two stock MAF's is parallel with the ECU
>>>only connected to one MAF (but air flowing through both) and then using an
>>>injector twice the size the computer thinks it is. It is VERY important to
>>>design the air intake so that the same air flow goes to both MAF's - test
>>>it on a flow bench with a voltmeter if possible.
>>>
>>>
>>>Jason
>>>
>>>
>> 
>