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Target lambda from dyno to road differences

Practical Dyno Tuning

Discussion and questions related to the course Practical Dyno Tuning


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Hello,

I have run into an issue where I tune the car on the dyno using steady state methods with the same air temps and coolant temps +/- 10 degrees Fahrenheit difference in air temps and then when I drive the car on the road air temps are still +/- 10 degrees Fahrenheit and the fuel mixtures are excessively rich all across the map. And by excessive I mean a target of lambda 1.00 and actual is lambda 0.82 also transitioning from 100kpa to 150kpa I am 10%rich. I have all the injector data entered from injector dynamics.

I tuned the car while the car had transient enrichment enabled. Could this have effected the fuel this much? What can cause this situation?

I did not have any fuel trims active.

Should I turn transient throttle enrichment off during the tuning process ?

I apologize in advance for lack of information.

Thank you.

Regards,

Luke

Without a little more info it's hard to be specific unfortunately. Really we would need to have some logs of exactly what was influencing the final fuel delivery while you were on the dyno - Basically any trims that could be influencing the results. I'm a little suspicious of the transient enrichment however that normally ends up with an excessively rich mixture when it is active if it's set up wrong which is the opposite of what you're seeing. this occurs when the transient is too sensitive or you've got noised on the TPS that is bringing in unnecessary enrichment.

I have the transient enrichment active when tuning on the dyno but it's a good idea to watch your various fuel trims to see if any are doing something they shouldn't.