Re: IAT range

["Jeff M" <tystorm@email.msn.com>]

I tried a switched resistor on a old TPI and found it did not work ;-(.  I
(much) later learned from someone that the ECM will not look at instant
reading changes to the IAT sensor.  Since GM ECMs are all a bit different in
many areas, don't know if this is always the case but, just thought I would
mention. Also I agree with Bruce and others that IAT in the manifold (vrs
the intake hose/air filter box)is better as the air does heat up a good deal
while bouncing around in the intake and head ports, until the valve actually
opens.  Runners and especially ports are relatively small and the air trying
to be there and travel through will pick up a good amount of heat.  Air
going across a surface will cause friction to an extent and will pick up
more heat than standing still as I recall.  Also, the GMECMs from what I
have seen, use engine temp to (cannot remember exact word, long day) bias
IAT so that the reading is more accurate, since we all seem to agree that
low buck OEM IAT sensors are slow and not very accurate.  Last point is, if
you can tune the fuel from the fuel system and/or chip then this is the way
to add fuel, doing the IAT relocation only works if your chip is lame on
acceleration fueling and you cannot make the changes to address this.

Jeff M

> heres my take on the IAT/MAT situation.....relocating the entire sensor is
a
> particularly dumb idea, many people have already pointed out the problems
> involved with it so i wont get into them...however, placing a resistor
inline
> with it and running a toggle switch might be cool....i mean, the ecm runs
the
> engine extremely rich at WOT as it is, but if youre gonna be racing you
might
> as well throw that in there anyway...i believe the timing gets bumped
> slightly too, and then you can run with it normally 99% of the time.




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