The V8 Owners Forum -

Hi everyone,

I'm running a Range Rover 3.9 with an aftermarket EFI on it. I won't mention the brand as it is not relevant and not here to promote or bash. I am trying to improve mileage and that is also why I installed it in the first place. But instead it is worse than original. I am now experimenting with running it lean but I know you can't run it too lean as you will start burning your engine. What is the leanest safe AFR setting. Either as a target AFR or actual AFR when running? I'm also dying to know what the settings would look like in the original ECU. I'm running a slightly faster camshaft than original due to an engine rebuild.

Many thanks.

Wam

Leanest may not be the most efficient.

Lean at low load/part throttle, you are unlikely to harm anything.

Lean at full load, is idiotic.

In many respects, you want to achieve the best torque, for any given load, as then you can use less fuel/air to make progress. And leanest is not going to achieve that

And unless you are monitoring all 8 cylinders individually, You're only guessing what each are doing if you're trying to push limits. Not a good idea.


The best control over fuel economy, is your right foot on an otherwise well tuned engine