AFR numbers

[T2Andy]

What and how is lambda calibration ,is it important

[A80Avant]

only needed on wideband lamdas. It has to do with what the probe can measure as 14.7 mixture so that it can then show all the rest of the values properly. All standalone systems have a routine to make the lamda calibrated. VEMS has its own.

[Rocco]

it is dangerous for our engines under full acceleration and foot down the lambda numbers like 0.90/0.95 , that´s the same as 13´2/14.0 ..... ????????????

[Rocco]

it is dangerous for our engines under full acceleration and foot down the lambda numbers like 0.90/0.95 , that´s the same as 13´2/14.0 ..... ????????????

one up for this thread

i would love to know the question as i´ve marked

someone with engine tune knowledge can help??

[GazzaG60]

its dangerous for all normal gas FI engines that. its on the lean side. more NA numbers id have said.

over 12.5 and its getting lean.

a general rule of thumb is 14-15:1 on cruise and 11-12.5 for boost. i tend to aim for 11.8 or so.

its worth noting the accuracy of wideband sensors is not so good at the cruise levels as a narrow band. wideband is better at the extremities of the ranges more so the lean and the rich.

[AUDIS2avant]

I´m running 12,2 on WOT and 98ron in my cossie, with app 650bhp and it´s just fine, egt in collector is arr 950-970` and 21deg advance.
Would say no higher then 12,2-12,4 on WOT for drag, and 11,5 for topspeed.
As espen says, with the right fuel, you can go higher afr cause of the better coling features in the fuel but not on normal gasoline

[EspenW]

On gasoline, aim for around 11.5 at mid to high rpms (where the exhaust gas temp starts to skyrocket).
On E85, we often go leaner (0.85-0.88) as stoich is 9.6 (in petrol terms) and the cooling properties of ethanol are much better.

On my K-Jet Lambda Golf (USA spec), there was no full throttle switch (unlike the GTI model), so the car was running at stoich (14.7 / lambda 1) even at full throttle.

[EspenW]

Good point about top speed runs and drag/normal driving as well. Huge difference between pushing a car for minutes at WOT on the autobahn and occasional 2.7 second bursts of WOT from 60 to 90mph.

[Rocco]

BIG many thanks for all these coments


it´s very nice to learn day a day few to few with all of you

-Tomas-

[Simons]

[QUOTE=Rocco;460615]it´s very nice to learn day a day few to few with all of you
QUOTE]

I think the same as you

[Faheemo]

Hey guys i'm rather new to tuning, but my figures are close to what been mentioned above - i'm Running my car on 102 Octane with 2 bars of boost, 22deg of timing and AFR @ 11.8 - 12.0.
The car runs very well once she is in boost but i would like to know what would be optimal timing to run before the boost comes on , to reduce lag ?

[GazzaG60]

no hard and fast rule. lot depends on compression ratio etc.

best way is a set of det cans to listen for knock. one way is to advance slightly. you will feel or should feel the changes as it gets too much. power increase stops as does the cooling effect of the advance.

[Faheemo]

I've got a logging device with a knock sensor that makes it easier , so I was looking for a quick
Rule of thumb that says you can run xx amount of timing b4 boost kicks in and then take it from there.