cat...

[xxalexx at ix.netcom.com]

Cat is too hot, too control emissions use air only when engine 
warming up.  If car has a O2 system turn air off when O2 is cycling   
Look at your vacuum diagram under hood or other schematic 
for a diverter valve and/or airpump, or aspirator.
Check ignition timing it might me too retarted to prevent detonation.
Might look into reprogramming curve for retard only at high boost.
Leaning mixture will make engine hot, untill you reach about 20:1
then if still running has a cooling effect. 
 alex 
 
> While we are on the subject of cat's, I have a sort of EFI related question
> about cat's more especially on that rotten egg smell.
> 
> First thing's first a description of what we are all up against.
> 
> 1984 RX-7 13B with a Vortech supercharger, SDS EFI 2 primary and 2
> secondary injectors of 50lb/h ea.
> 
> Exhaust temp at idle is 750Deg. F WOT is 1475Deg. F the thermocouple is
> about 2.5" from the exhaust ports; the exhaust is a custom-made 2.5' pipe
> with a hi-flow 3 way cat and a Borla muffler.
> 
> I am bypassing a small quantity of compressed air from my Vortech to the
> air tube in the cat, but I am getting a very bade rotten egg small from my
> exhaust I am leaning out my AF mixture but now I am at a point where I am
> afraid to lean out more and kill my engine and also I get a bit of stumble
> if I do lean it out more, the AFR monitor that I use is one of those cheap
> ones, It reads a bit riche.
> 
> What is a guy supposed to do run a car that smell's like rotten egg's or
> pull the cat off, or get a reel air pump and loose a few HP?
> 
> Alain Marchildon 
> 
> 
> 
> 
> 
>