wisner955

When on a dyno using an up the tailpipe wideband O2 sniffer what is typical effect on A/F ratio of a catalytic converter?

Is there a rule of thumb for this?

Paul

wisner955

Well, I guess it's either;

1) Dumb question, everyone should know this.
2) Forum has a rule, "Don't talk to the new guy".
3) Tuners/dyno owners don't know.

wisner955

P Mack

iTrader: (6)

Not a dumb question. Next time I dyno I will compare my wideband to the dyno wideband to see what the difference is. Either that or i'll try the wideband in the precat and post cat o2 bungs on the same tune. Might not be for a while though.

dynocar

In the mediam to high RPM at WOT, we have never noticed a measureable difference. This potentially occurs for these reasons, the CATs are designed to operate at a 14.7:1 A/F ratio for proper catylitic action and we should be more rich and the exhaust gas volume/velocity is too much for the CATS to do anything measureable. As far as using two different wide bands for a before/after CAT test, I think the two widebands could each read slightly differently skewing your results. EJ