Re: please explain


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Posted by Ben (76.14.17.32) on 17:19:32 01/03/08

In Reply to: please explain posted by Peter

Cheyenne, always thought you were a pilot ?!? Now find that you are a 'real' techie! Cool!!!!

Here is my view of it and agree with Blaine. I'm still using a modified 180*F stat (3/32" dia hole)

Closed loop is when the computer system can sense the mixture/exhaust and then meter it according to
the algorithms (look up charts) the software has.

Open loop is when it is blind because no feedback (the various sensors & systems are not up to temp,
or spec), so it meters fuel at 14.7 (air to fuel), or at the stoichiometric (STOICH) ratio.

When in closed loop, it can meter accordingly and gets the cleanest smog numbers. In open loop, that
might not be the best ratio and would then be 'dirtier' for smog.

For most GM vehicles, that temperature where the sensors and systems are to spec is at 170*F.

Now to the generalities of things. All OEMs design and product vehicles (except for specialty) for
the 'general' public. Meaning the middle of the bell curve. "JUST GOOD ENOUGH" kind of
stuff....but....for smog, they go towards the extreme end of that bell curve. Mainly to squeeze
out as much performance to get the numbers.

Also understand that a vehicles thermal management system is a huge *SYSTEM* and dynamic. Very
dynamic with many, many variables.

Pushing the cooling system towards the max temp gets the best SMOG numbers, but leave little head
room for high ambient and/or severe duty (towing, etc).

By spec'ing a 195*F thermostat, they pushed the thermal envelope close to the upper limit to get
the best SMOG numbers, consistently/reliably/etc.

By putting in a 180*F thermostat, it provides more head room for performance and reliability, but
still meets SMOG, as the computer system is above 170*F.

I like to increase the stat hole (there is one already....a teeny weenie 1/64 dia hole) and by
going to a larger hole, reduces the hysteresis of the system.

As for any mechanic getting excited about a non spec SMOG component (the stat is part of the
listed SMOG component/systems). They are licensed by the state and that is also governed by EPA
(government). Which means they can lose their license, shop business license, certification,
fines and even jail time.

So that is a "don't ask, don't tell" situation with any licensed mechanic. It's against the law
to put in a non-OEM SMOG component/system.

Cheyenne, what do you know about solid state compressors? I bought some IP for Sun Micrsystems
preparing for hotter chips. Refrigeration and wanted something with no moving parts, scaled from
postage stamp to tonnage. My physicists didn't believe it, but after the demo, jumped all over
it, so I convinced the President & CTO to authorize. I purchased it out from under Intel,
who were also bidding on it.






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