More Horsepower. More Torque!!

[Marc Randolph]

On Wed, Mar 31, 1999 at 09:27:31AM -0500, David A. Cooley wrote:
> >>From what I've seen, it depends.  Some custom chips are open-loop
> >(offroad) only, while others (especially Calloway and Lingenfelter)
> >actually attempt to make their calibrations 50 state legal (unless you
> >request an offroad chip).  Others just shoot for 49 state.
> >
> 
> Actually, the chips are still closed loop... (looks to the O2 sensor for
> feedback) until WOT, then it's still not open loop, it's in Power Enrichment
> mode... It ignores the O2 sensor and adds additional fuel.  The fuel may or
> may not be trimmed by the long term learning of the PCM depending on the
> cal...  The offroad only designator just means they didn't take the time and
> money to have their chip emission certified.

I've come across a chip or two that actually has closed loop mode 
disabled (via setting the coolant temp real high) so you are always
running in open loop.  Anyone have ideas on why a chip maker would do that?

> You cannot use a standard O2 sensor to judge your mixture...  800mv in one
> car may be 12.5:1 and it may be 13.9:1 in another...
> an EGT guage or a wideband (A/F meter) sensor is the real "safe" ways.

That was what I thought.  Thank you for confirming that.

> Why wouldn't you be street legal?
> If you still have the bungs for the O2 sensors and if their is AIR injection
> and the headers have the AIR injection ports, then they will still be street
> legal.  The exhaust manifolds aren't considered part of the emissions
> equipment unless the O2 sensor mounts in them or they have the AIR fittings.

Sorry, I should have stated more properly that if you remove the cats,
you aren't street legal.  When I said that, I had in mind the ZR-1,
where the cats are attached to the exhaust manifolds, so going to headers
would mean no cats (unless you pay even more for headers with cats). 


   Marc

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  Marc Randolph     -    mrand at pobox.com    -     PGP keyID: 0x4C95994D
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