Typical valve noise? Lambda correct?

[dsmithwc04]

I was letting the car idle while measuring the idle lambda reading to confirm it was working and found my CDS copilot to report that the WBAF-2 was giving me a reading of .8 volts at idle. This equates to 11.8 lambda. The motor was warm and water temp at aprox 165F. I think that is slightly more rich than I would prefer but wanted to see what you guys were measuring.

Also, how loud are the valves on this motor while idling? With the motor idling and warm there is some valve tick about the same level as a midyear Miata with the "HLA" tick. Wanted to confirm this is normal as I can't remember hearing it the first time I idled the motor before taking half the car apart to go do a thorough check of the car since it is new to me.

[Jeff Read]

The valve tick is normal

[dsmithwc04]

Thanks Jeff. It sounds normal but I didn't remember hearing it the last/first time I started it.

[mikey]

tick is normal. don't worry about trying to convert lambda to a/f ratio. it is a highly complex conversion depending on a bunch of factors and not always straightforward math. bottom line, stoichiometric for any given fuel is not always the same ratio. but when reading lambda, 1.0 is always 1.0. target on PFM is 0.89 at WOT, imagine you'll want to be in that ballpark of 0.88-0.94 at WOT. Part throttle, idle, off throttle readings don't matter, just focus on the full load acceleration WOT number.

[dsmithwc04]

Thanks Mikey. I will shoot for .87-.89 at WOT since that is what SCCA Enterprises shoots for when running the motor on the dyno.

[Marshall Mauney]

Remember that it's WOT under full load in top gear, and it takes some time to stabilize.

The only data point that you should care about is the value under full throttle at the end of the longest straight. Everything else is noise. At Road America, it's right before braking going into Canada Corner (assuming you're flat from T8-T12). At Blackhawk it doesn't matter enough to care about, as there are no straights long enough to get good A/F data.

I strongly recommend being conservative for your first few events - a few points richer won't impact your lap times, and a few points leaner can damage the engine. It can be an expensive lesson to learn.