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VE Tuning

Practical Dyno Tuning

Discussion and questions related to the course Practical Dyno Tuning


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link to video: https://www.hpacademy.com/dashboard/courses/practical-dyno-tuning/step-7-steady-state-fuel-tuning-using-the-dyno-to-tune-steady-state-fuel

at 1:25 you mentioned that only the target lambda has to be changed. I thought the target lambda table is just used a reference for the tuner in the ecu when tuning the VE? How is simply adjusted the target lambda table sufficient to adjust the remaining tables when making AFR changes?

I am yet to use a dyno to tune a car but I cant understand how to increase the load on the engine by depressing the accelerator pedal and not have the RPM climb. Am I missing something? Is this why you need a load-bearing dyno to keep the revs constant?

the method andre uses at 7:15, if its simply a gradual increase of load and youre not making an calculations on the fly, how do you determine the factor by which you would increase the entire column of VE by since the measured AFR is fluctuating so much?

This is the operating principle of a VE based fuel model. We adjust the VE table until the AFR matches the values in the target table. Once we've done that, the VE table should be an accurate representation of the engine's VE. If the ECU knows this and the size of the injectors fitted, it can decide what pulse width to deliver to get a specific AFR and hence if we want to change the AFR the engine runs we only need to alter the AFR target table.

Thanks Andre. im still abit lost on the other 2 questions though.

1) I am yet to use a dyno to tune a car but I cant understand how to increase the load on the engine by depressing the accelerator pedal and not have the RPM climb. Am I missing something? Is this why you need a load-bearing dyno to keep the revs constant?

2) the method andre uses at 7:15, if its simply a gradual increase of load and youre not making an calculations on the fly, how do you determine the factor by which you would increase the entire column of VE by since the measured AFR is fluctuating so much?

Yes, you need a load-controlled dyno to do steady-state tuning. The dyno will have a method to set the desired RPM.

You can basically follow the trend. If it's been 10% lean, you can add 10% fuel to all cells from the current one to the maximum load for that RPM column. So that the mixture will be closer when you get there.

Hi David, any idea which load bearing dynos allow that? Andre mentioned in the video that one would have to control their foot to stay in the middle of the cell and that left foot braking would have to be incorporated when tuning low RPM and high load...

Load bearing dynos can be had from practically all manufacturers -- Dynapack, Mainline, Mustang, Dyno Dynamics, Land & Sea, Rototest, even Dynojet (but the majority of Dynojets are inertia dynos, and don't have the load bearing addition).