More Horsepower. More Torque!!

[Roger Heflin]

On Wed, 31 Mar 1999, Marc Randolph wrote:

> 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?
> 

It tends to run better, and is easier to tune than closed loop mode.
So if someone wants to get a car to run good (but bad gas mileage)
that is the quick and dirty way.

Mine went into permanent open-loop mode a couple of weeks ago, because
the knock sensor failed (I actually debugged it, and the knock sensor
in the block has infinite resistance, and it is supposed to have about
4k ohms).  After I replaced it with a resistor (3.9k) it went back
into normal operation.  Since I have not ever identified knock with my
engine I am not worrying about it until I redo the engine, with the
cam  I have and stock compression I have been told that real knock is
pretty unlikely, and I tested with 5 gallons of 104+about 5 gallons of
91 and the knock sensor went off in exactly the same manner, so I
wrote the knock off as being false).

> > 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). 

that would do it.   On the LT1 most of the cats are after the headers.
> 
> 
>    Marc
> 
> -- 
>   Marc Randolph     -    mrand at pobox.com    -     PGP keyID: 0x4C95994D
>    "During my service in the U.S. Congress, I took the initiative in
>     creating the Internet."   - US vice Pres. Al Gore in an Mar 9, 1999
>               interview on CNN somehow claiming he created the Internet
>       
>