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Fuel table tuning

Webinar Questions

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I think it was this video that you said that your normally only accelerate WOT for short periods of time so you don't need to add fuel for cooling. In the case of a track day/ weekend car. How would you go about selecting an target AFR or work out how much extra fuel you would need to add for cooling?

Tracks also normally really hot well where I am located, would you tune IAT to pull ignition or add fuel or both?

The AFR you choose to run will depend on a number of factors - Specific power level of the engine, engine aspiration, fuel, boost level (if applicable) and usage of the engine. It's likely that for a dedicated track car you would want to use a richer WOT AFR than a street car. If you want a more thorough explanation of this as well as how to decide on an AFR for your application I'd recommend checking out our Understanding AFR course.

The fuel delivery vs IAT should be dealt with adequately in the IAT fuel correction or the actual ideal gas law equation. Unless you decide that you want to target a richer AFR at higher IAT.

The ignition can be trimmed relative to IAT to avoid knock and normally I'll check this on the dyno. Regardless of the ambient temp on the dyno, it should be relatively easy to check the ignition requirements at higher IAT and see if you need to retard the timing to avoid knock.

I'm sorry to take this old thread back, but I've just joined the HPAcademy, and after the EFI tuning foundamental course I'm trying to view the past webinars that are very intresting. I'll take the road tuning course for sure, but I have a quick question on AFR:

you said in the webinar that AFR can be tuned manually or with the help of the ecu with the closed loop function if I understood well. Since I'll approach road tuning, supposing that I will be alone with no passenger help, will a recorded log session in closed loop help me once I stopped to optimize the fuel map?

Sorry for any language errors! cheers

Welcome on board cabletie!

Yes you can allow the ECU to run in closed loop and then use the resulting data log to help you fine tune the fuel table. in particular you would be wanting to pay attention to the closed loop fuel trim being applied to get the AFR on target. If for example your AFR is on your current target but the closed loop trim is -8% then removing 8% fuel from the zone that the ECU was accessing at the time should correct this error.