Correct AFR

[Laaf]

Right on startup, when the engine is cold, should it still be 14.7?

As the ECU is running cold start enrichment then, no.

[EspenW]

Right on startup, when the engine is cold, should it still be 14.7?

14.7 when the sensor has warmed up and the ECU reads its signal. This takes a little while.

[ineora]

Right on startup, when the engine is cold, should it still be 14.7?

[prj]

Depends on the software it's running.

Stock runs mid 12's on WOT, but there's hardly any boost.
Most power on these engines is at about lambda 0.8, which is 11.8 in AFR terms.
Of course on the top of the rev range, it makes sense to go richer for EGT control.

After about lambda 0.78 or 11.4 AFR you start massively losing power.

Idle should always be lambda 1, 14.7 for gasoline.

[ineora]

Idle

Is that a correct value on idle too? On a stock non modified Engine?

[Rusty]

High 11s low 12s

[twoqu]

http://www.s2forum.com/forum/showthread.php?t=68814&highlight=afr

[HMS-S6]

Yeh, mines dipping to 10.8 or so on WOT so obviously not a fuel trim issue it would seem. Still edging for a hiding boost leak maybe!?

[UrS4boy]

Hi all, I've finally dug my S6 out and fitted the wideband I bought for it over two years ago! What figure would you typically expect on wot from 3,000 to 5,000 rpm?

Hey there!! Long time no post? Hope things are good.

As for your question, my off the top answer was going to be an AFR of around 11. Here are some UrS AAN dyno results that back that up:

[Jaswan]

out of curiosity what brand have you/did you go for?

thanks

[HMS-S6]

Hi all,

I've finally dug my S6 out and fitted the wideband I bought for it over two years ago!
What figure would you typically expect on wot from 3,000 to 5,000 rpm?