Discussion and questions related to the course Road Tuning
Going to be doing some road tuning soon. Will be left foot braking to reach the whole fuel map.
I had the idea to temporarily retard the timing a few degrees to reduce power. That way we might be able to left food brake longer without overheating the brakes. Because the brakes would be absorbing less energy. But I'd still be able to accurately tune the fuel map.
Would this make enough of a difference to be worth trying? And how much retard is reasonable at various rpm?
I guess it would work for just the lambda, but not sure why you'd want to do it.
You will put less energy into the brakes, but you'll be putting more into the exhaust valves, manifolds, turbine and housing, etc. Of those, the turbine fins may be the most significant as they have a maximum operating temperature.
All in all, I'd suggest warming up the brakes first, keeping the loading down below the point where you feel fade starting, and allowing a good cool-down period between trials.
Best thing would be to check if there's a decent dyno' operator in your area - maybe get a rough 'tune' first then finalise it on the dyno', if possible? It costs a few $$$s, but that could be less than a traffic ticket or brake rebuild.
High temp pads and a good long hill. Don't get greedy on load time, if it isn't brakes it may be something in the engine bay or under the car that cooks it if keep laying into it at low speed. You may find you can get most of the data you want with datalogs and a good interpretation package.
I saw this done this on a twin-turbo charged land-speed record streamliner. They dialed the ignition back to reduce the rate of acceleration, limited the boost, and made "full pulls" in the garage to verify the fuel map was in the ballpark.