[kevinca]

Here is a tech question for the gurus.

When dynoing a car assuming the car HAS a cat, does placing an 02 sensor at the tailpipe show different O2 levels than bolting in a straight pipe for the dynoing process?

A guy I spoke with said the amplitude is the same so it shouldn't make any difference, but he wasn't 100%.

Any takers?

 

[Gvtec]

I was always under the impression that the O2 measures the ratio according to the exhaust gas temps. If this is correct, one needs to place the probe in front of the cat, as the gas is superheated after that point.

 

[MichaelDelaney]

we place the Horriba wideband at the exhaust tip when we dyno tune. The assumption is the change in the reading before the cat is removed proportionately by the cat, before and after a tuning adjustment.