THAT'S WHY WE NEED THOSE MOPAR COMPUTERS...NOW!!!!!
Dr. Pat
----------
>From: "Bridges, Bruce" <bbridges@alarismed.com>
>To: "'dakota-truck@buffnet.net'" <dakota-truck@buffnet.net>
>Subject: DML: RE: Computer cancels out mods (was: New Member Intro)
>Date: Tue, Jan 19, 1999, 11:10 PM
>
>Fish,
>good Q... Pure speculation based on various observations but heres an
>attempt to describe and explain:
>The O2 sensors control mixture settings by teling the computer if the engine
>is rich or lean. If they go lean, the pulse width to the injectors is
>increased. If they go rich it is decreased. add more air, and youd expect
>more gas, right??? wellll, you get the additional pulse width below a
>certain RPM, but by looking at the Pulse width on during WOT, no matter what
>air you put in, the pulse width appears to be "fixed" at the higher (4600+)
>rpm ranges and caps right at about 80% duty cycle of the injectors. Big
>injectors you say? well, it still caps the pulse width changes, but thats
>after it has reduced the pulse width to get the right mixture in closed loop
>No more fuel = no more power gains...Think of it in an EPA way: This engine
>will make no more than x ppm of these pollutants... clogged airfilter, no
>airfilter, clogged muffler, no muffler etc,etc. all normal situations but
>equivalent to making "modifications" in the way they require the engine to
>respond. This may be/is way to simple since many other factors come into
>play too! Manifold vacuum signal should be lower due to better Volumetric
>efficiency, signalling more gas and air...BUttt etc.etc. wondering how the
>computer will make up for 1.7 rockers and a R/T package camshaft...
>Bruce
>
>-----Original Message-----
>From: David Fishman [mailto:fish@chips.Eng.Sun.COM]
>Sent: Tuesday, January 19, 1999 2:52 PM
>To: dakota-truck@buffnet.net
>Subject: DML: Computer cancels out mods (was: New Member Intro)
>
>
>Mssrs. Bridges and Short state that the '99 computer cancels out the
>effects of bolt-on mods.
>
>At the risk of sounding dense, how would the computer (specifically)
>cancel out the increased exhaust flow from headers and catback exhaust?
>Slow down air intake? increase fuel injection rate or volume? Please
>'splain.
>
>fish
>
> David Fishman, San Jose, CA
> fish@ihot.com
>
> 97 BMW R1100RT
> 99 Dodge Dakota SLT+ CC 5.2 4x4
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