MAF

[Greg Hermann]

>soren wrote:
>
>> >170 Gm/sec works out to 300 cfm (and about 205 HP) (at sea level), which
>> >works out to 84% or so VE--on the low side, which indicates a lot of
>> >restriction from the MAF!  If the thing only has a 25 mm diameter throat,
>> >your MAP at WOT can only get up to about 12.0 or 12.5 psia. (Basically ,
>> >the MAF is throttling the engine!)
>>
>>     First of all, isn't the "95 3800 rated at about 205 HP? Second, after
>> working in a Buick garage for 4 years, I am pretty sure that MAF sensor is
>> not 25 mm in diameter!
>
>He prolly meant 25mm radius... 50mm sounds about right on a car putting around
>200hp.

I would agree--that amount of air-flor through a 25 mm hole would not be
particularly within the realm of possibility for making 200 HP.-- But I
will maintain that a 60 or 65 mm diameter MAF should give a substantial
boost in top end performance over a 50mm (if that is what it really is) for
an engine of this size with the other stated flow enhancements (bigger
exhausts, etc.) If the available MAF instruments are not sensitive enough
to give usable and repeatable readings with this much of a size increase,
they DO deserve to be on the junk pile!!

Another, possibly dangerous, thought: has anyone thought of running TWO
throttle bodies (acting in progression, like the primaries and secondaries
of a four-barrel carb, with TWO MAF's?? (maybe even a stock size primary,
and a larger secondary one?? This would indeed be an interesting electronic
project--come up with a way to combine the outputs from two, progressively
used MAF's into an input which a (nearly) stock ecu would accept as if it
had come from a stock single MAF sensor!! No deterioration at all in bottom
end response or mixture control, and gobs more airflow whenever one cared
to ask for it!!

Regards, Greg
>
>Ciao,
>Francois Dion (francois at hyperreal.org)
>--
>Member: FLU #1722, PCNA
>http://www.fortunecity.com/silverstone/zagato/101/launch.html
>Alfa Romeo, Fiat, Lancia, Peugeot, Volvo, Solex