Safe Air/Fuel Ratio?

[Element]

What is considered to be a 'safe' air/fuel ratio?

 

[NCZ13]

stoich (14.7)

its also a bit safer to run a little rich, than lean as well

 

[Element]

stoich (14.7)

its also a bit safer to run a little rich, than lean as well

Really? For some reason I thought you wanted to be below 12. I just was looking at my AFRs at WOT and I'm anywhere between 10-11.

 

[shane02pro5]

Under boost you want 12.2 and under. Stock tune has you running very rich.

 

[Element]

Under boost you want 12.2 and under. Stock tune has you running very rich.

Alright so I'm still safe. Thanks!

 

[NCZ13]

Really? For some reason I thought you wanted to be below 12. I just was looking at my AFRs at WOT and I'm anywhere between 10-11.

he didnt say if it was under load, or just idling.

So i just gave a generic answer.

 

[Element]

he didnt say if it was under load, or just idling.

So i just gave a generic answer.

Yeah my bad. Sorry about that. I meant at WOT.

 

[Bravnik]

The jury is still out on what is safe on our cars due to DI. BMW runs their DI engines at 13 WOT. I have ran mine at 12.5 without issue. However, the rule of thumb is 12 under WOT as the number to shoot for.

 

[becks]

Is it around 14.7 stock (without a tune)?

 

[Bravnik]

Is it around 14.7 stock (without a tune)?

At Idle even with a tune it will be 14.7. At WOT I have seen stock cars in the 8's and 9's and never in the 10's. Fully bolted cars without a tune are typically in the low 10's dropping to 9's.

Tuned you should look at 12's when WOT.

 

[H3br3w_Ham3r]

I'm running 9.5 at WOT on the dyno which is insanely rich. I'm hopping the intake will help that number.

 

[bykeryder4life]

idle should be 14.7 and at wot you should shoot for 11.7-12.0. This motor has the potential to run leaner actually because it is DI, the bmw's run in the 13's at wot and full boost. On this car though, I would not want to see any leaner than 12.0 and no richer then 10.8 at worst

 

[becks]

Sorry I've got a stupid question, what is WOT?

 

[Cue]

Pedal to the metal = WOT - Wide Open Throttle..... Something our cars CAN'T DO ..lol

 

[becks]

^lol....thanks

 

[Larimer]

As lean as you can get without it knocking. 12 seems high but I've never messed with DI cars before.

 

[shane02pro5]

I am not DI running 22psi at 12-12.2 with 0 knock but at 8.5:1 according to my J&S.

 

[Cue]

As lean as you can get without it knocking. 12 seems high but I've never messed with DI cars before.

Agreed... With my CX7, 11.6-12.2 (4400rpm to 5500rpm WOT) is the highest I can get it on a knockless tune... that and 94 octane....

 

[PCspeed3]

wierd, I searched for this safe AFR today and looked at this post earlier haha. Mine reads around 14.4 at idle, havent looked at WOT yet...

 

[shane02pro5]

CX7 has a smaller turbo that may be working a little harder causing higher intake temps...