TPI Questions

[Tom Cloud]

James Boughton wrote:

>EGR is used to decrease NOx emissions, as well as to dilute the
>incoming mixture to improve fuel economy.  Because EGR causes
>the burn rate of the mixture to decrease the spark advance must be
>increased.  So for an engine calibrated with EGR there is a spark
>advance increase any time the engine controller thinks the engine
>is breathing in EGR.  The problem with removing the EGR valve
>is that some people don't let the engine controller know that EGR is
>not functional (to keep the check engine light from coming on).  This
>means that the engine controller thinks you have EGR when you really
>don't and therefore the spark advance is far more than what it should
>be.  This can cause very high peak pressures and possibly knock.
>I know when I did this I holed a piston:-P  I wish somebody had told me
>what I am telling you.

so, James, on a non-ecu engine (distributor with
centrifugal & vac advance controlling timing) how would
you recommend compensating for the "loss" of the EGR
function ?    I had my distributor "re-curved" (actually
think he just set the vac advance spring a little stiffer
 -- talking Ford vac advance canister)

Tom Cloud