You don't and can't that exactly. Like I mentioned above, some fresh air/fuel goes right out into the exhaust.

The more boost and/or cam you use, the less exact it is.

Now, that said,once you get the motor to run exactly how you wan, everywhere, you not what those measurewd A/F's are and use that to see if anything changes later on.

It's a tool, pretty damn good tool, bu hardely anabsolute..

All my opinion with some fast thrown in.

Sorry guys...alot of my butons are sticking. I think some poppyseeds / sesameseeds from my bagels this week-end got jammed under a bunch of buttons...Especially my T buton and space bar.

LOL.

Come on tell the truth what's the real reason for the sticky...ing keys?

Would you believe I had 4 egg sandwiches and 7 bagels ?

I don't eat breakfast all week. I load up on the weekends. LOL.

You should see my keys roll than crack.

Definately seeds.

Oxygen sensor readings aren`t accurate. When you buy a new sports car none of the manufacturers depends on 02 reading to keep their motors safe or to run their fuel curves and maps, they send a Tech out every few months to read the plugs and make adjustments .
Got it!

Dan, I have yet to have a tech guy come. Its been over six months since I got my Vette. Should I call the dealer or does GM send the techs out? If its GM, do you have the number for them?

Bananarama, I`ve heard we could have a repeat of the Great Plug Readers Strike of 1908. Oh the HORROR and grid lock!! No piston was safe!

Ok so now we are comparing a motor that has had millions of dollars of engine analysis done at an OEM's level to a "custom" motor with $500 worth of dyno work.

Don't forget all the "desktop" dyno hours BB.
Makes all the difference man!

I do agree a plug reading can give a good indication of the heat range, timing, aluminum speckles, etc.

I just will not, in this day and age, tune a high performance marine engine, looking at plugs. A basic 400hp deal, maybe. But certainly not going to build a 700,800,900, 1000hp + pump gas marine engine, and go out "plug reading", trying to get the ideal timing and fuel mixture. I remember back in the days before guys would use widebands, whether on the water, or even the dyno, and many many times, engines were being pulled due to carnage. Thats why in this hobby, 15-20 years ago, very few running around with a pair of 1000HP pleasure use marine engines. Now, its the norm.