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Choosing the correct A.F.R

EFI Tuning Fundamentals

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Discussion and questions related to the course EFI Tuning Fundamentals

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Hi, I heard something about when the car is almost close to redline, the A.F.R must be richer or leaner, I don´t remember? Does someone know something about this? And at idle cars with aggressive cams and e-85 must be at 0.95 lambda because if it could be at 1 lambda it could end with unburned fuel in the exhaust making inaccurate reading?

I may be mistaken, but my thoughts...

I haven't heard of this, there 'may' be an arguement for running a little richer to keep EGT lower around peak power/torque, but approaching the 'red line' is a new one on me.

0.95 vs 1.0 lambda is actually richer - there may be some confusion with unused fuel passing into the exhaust on overlap and/or the poor combustion that can occur from exhaust dilution?

Hi Gord, Yes I think I´m a little bit confused with the last thing, about richer lambda causes too much fuel unburned and if it is too lean there won´t be enough fuel because of the more aggressive cam profile? And I think u are correct about richer a.f.r for the peak torque/power, maybe someone else can confirm? Thank u for the answer Gord

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