[s-cars] An interesting FMIC "fact" (?)

[Ned Ritchie]

Really big & giant intercoolers indeed create a lag created by volume.  

Some of us depending upon the situation. . .  Like desiring to keep
boost up will not use a by-pass valve relying upon the volume of the
intercooler to do two things:

Act as an accumulator to absorb the pressure spikes
Not have to be pumped up again after the pressure is relieved.

The "constant air" system on the S1 kept the throttle partially open to
maintain 4000 rpm retarded the timing lots, and by-passed excessive
boost during shifts into the exhaust manifold.

Lots of flame, popping, & explosions, but no lag.

-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com] On Behalf Of Kirby Smith
Sent: Saturday, February 28, 2004 11:42 AM
Cc: s-car-list at audifans.com
Subject: Re: [s-cars] An interesting FMIC "fact" (?)

This discussion raises a question that the chip reprogrammers might be
able to answer: Is there an intake flow time constant accounted for in
the ECU code?  Specifically, with a giant intercooler, there will be
more lag between the mass flow at the intake manifold and mass flow at
the MAF sensor than with the stock IC.  Perhaps it sufficient to measure
the rate of change of throttle opening and adjust fuel flow
accordingly.  If I ever am able to upgrade my IC, I would prefer not
have a new "feature" of lean spots in the engine response.

kirby
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