Our performance suffers when the engine gets warm because of the location of
the IAT. The factory location wil read (in the summer) about 200 degrees. The
adjuster box doesn't fool the computer with the amount of air (we don't have
Mass Air Systems) but rather the temperature of the air. The temp is related
to volume, but not close to as accurate as Mass Air.
On the efficiency factor, they controllers are designed with a combination of
power and efficiency (leaning toward fuel economy). This isn't a bad thing,
but when trying to adjust for more power, the factory settings aren't quite
right.
On the Mopar PCM and Jet Chip, i'm not certain about Mopars compensations, but
the Jet does alter the IAT output slightly...for $250.
Why do we have an IAT sensor? Because the actual ir temp will be different
from cold start to normal operating temp. This means slightly different timing
and fuel enrichment for the cold to hot running conditions. (Just like the old
Chokes on Carburetors...only without the timing part involved.)
- Bernd
> I have more questions about this, please bear with me here... :-)
>
> OK, our performance suffers when the intake air gets too warm. As I
> understand it, the warmer the intake air temperature, the less oxygen
> actually gets into our engines (because air expands as it gets warmer).
>
> Evidently, now we can compensate somewhat with the IAT adjuster, setting the
> PCM input so it thinks it's cooler than it really is. But if the problem is
> that we're not getting enough air, how does fooling the PCM into thinking
> we're getting more air help? Does this mean that our computer isn't doing a
> good job setting the A/F ratio for maximum efficiency, or is it a question
> of optimum efficiency vs. maximum power? If it's the latter, wouldn't an
> aftermarket computer like the Mopar PCM or Jet chip address this?
>
> Or is it just that the IAT gives a "false high" reading because the engine
> compartment temps are higher than the actual air temp?
>
> One final question... if our engine has a temperature "setting" where it
> runs its best, why do we have an IAT at all?
>
> Sorry for all the questions -- I'm just trying to get a handle on the
> principles behind how this stuff works. :-)
>
> Thanks,
>
> - Alex
>
>
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:00:23 EDT