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Old 05-01-2008, 02:30 PM   #14 (permalink)
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Originally Posted by tasdrouille View Post
AFAIK IAT is not a primary determinant of timing.
I never said IAT is "the primary determinant of timing". Please don't try to misinterpret what I said. The ECU sets spark timing based on your RPM, then in addition to that it looks at load and intake air temperature. As the intake air heats up, the ECU retards timing and vice versa.
From my bmw repair manual.

From autospeed.
The resistor trick is based on this idea: you add the resistor to the engine coolant temperature sensor circuit, or the intake air temperature circuit. This tells the ECU that the temperature is different to its actual value, and as a result, the ECU adds more fuel (or less fuel, depending on the direction of the modification), or more ignition timing or less ignition timing (again, depending on which way the mod takes the perceived temperature).
Originally Posted by tasdrouille View Post
That is hardly dangerous unless you floor it, and is a non issue with knock sensor equipped cars.
At low RPM rpm, you don't need to "floor it" in order to reach maximum load and zero vacuum. The throttle body is sized for max load at max RPM. At low rpm you can reach max load at as little as 1/4 throttle. Hook up a vac gauge to your intake manifold and you'll see what I mean.

At this point we have no evident to suggest that a warm air intake will improve fuel economy by reducing the density of the intake air.

Last edited by tjts1; 05-01-2008 at 02:46 PM..
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