Frost

iTrader: (45)

Ed, I'm on the same page concerning converter operation. The examples I am citing do not have cats. Kevin Adolph, the [Ford] tuner and shop manager of Performance Auto Sport can (to his surprise) validate that he's seen repeatedly what I have said.

Without cal gases to check the equipment, there's no point in calling this scientific. I'm not talking about cats. The original poster asked if there was a typically a difference in AFR read from the tail pipe opposed to up front. This is the point sole point that I am relating. He didn't ask about taking the sensor from the tail pipe and putting it up front. I am not saying that everyone else will have the same results either. Out of the last dozen or so cars, the only one that broke the mold was a BS3 car, and it still read about .2 leaner measured at the tailpipe against it's own wideband.



Of course it won't be linear, and that's the one of the points of independent testing and calibration. Periodic testing with a range of cal gasses shows how irregular aging can be, which of course is environmentally dependent to a very large degree.

BLK02WS6

iTrader: (2)

I agree, at WOT, the sniffer is pretty close - but that is only good for those who throw it on the dyno for a couple WOT pulls and call it tuned...
Personally, I tune from idle all the way up with the wideband feedback going into my laptop for correction... don't see how you can possibly do that accurately with a tailpipe sniffer. And behind the cats will definitely be off at anything other than WOT, so if you are tuning the car properly, why not just put it in the collector for the entire tune and do it right...

Frost

iTrader: (45)

That's what I am talking about!

Black02SS

iTrader: (36)

Should be a sticky.