Hi what should the co level be set to on a stage two 2wd saff running greens t34, chip etc? is it better to set it slightly on the high side to keep things safe?

 

CO adjustment ONLY affects idle and light load mixture.
it does NOT affect on boost fuelling in any way.

Generally aim for 1% to 2.5% CO the lower the better but idle quality may suffer at lower figures
especially when running small plug gaps and/or cold running plugs.

 

ok thanks......

 

i thought the co adjuster was a global multiplyer

 

GARETH T, It is generally but only upto a pre defined boost limit.

Just image if it truly was, make a 5% span adjust at idle and the same amount would be HUGE at the top end - not good !

 

depends on how you adjust the co, if you do it with the FPR then its global

 

Interesting subject this one - Like Gareth, I was of the impression that CO adjust had more effect in the loaded region than we would like..
A description of what the CO adjust really does and exactly what it affects would be really good Simon!! pleeese...

 

Rich,

here is a basic fuel calculation algorithm..... (sorry for those who dont understand)

OFFSET=MINIMUM_INJECTOR_PULSE_WIDTH
(this sets the basic minimum injector pulse width)

if LOAD < LIMIT then OFFSET=OFFSET+CO_ADJUSTMENT
(LIMIT is the pressure point at which CO adjusment is disabled)

BASIC_PULSE=OFFSET + MAP_VALUE[LOAD][RPM]
(This adds the offset to the map value taken from the 3D fuel map based on load and rpm.)

CORRECTIONS=START+COOLANT+CHARGE_AIR
(this creates a percentage value from coolant temperature and charge temperature)

FINAL_PULSE=(BASIC_PULSE/100) * CORRECTIONS)
(this multiplys the basic fuel pulse width with a percentage of corrections.)
(E.G fuel is enriched when the car is cold or charge air temp gets too high)


I have not included things like ACCELERATION,DEACCELERATION and STARTING fuelling
but it gives a pretty good desription of how nearly all ECU's calculate fuel.
There is much more going on in the background but it would take me all day to write out exactly everthing.

Looking at this, the mapper is able to set the point at which the CO adjustment is effective
so in theory the CO could be made to be global but I have NEVER seen
a chip that allows this to be the case above about 5 psi of boost !

 

well i didnt know there was a point at which its disabled

 

Thanks v. much Si!!
I've printed that off, will take all that in later!!