MORE ON BRACKET RACING TUNE-UP FOR FUEL INJECTION

Question: How did you dial in your mechanical fuel injection setup for bracket racing?
Answer: Our tune-up is set up to be in a linear range. That is when we increase the shift point, our ET is proportionately lower. When we lower our shift point, our ET is proportionately higher.? That is a result of many characteristics from our combination, some intentional and some accidental.

I recall a setup many years ago that was not linear. If you raised the shift point beyond a certain point, you slowed down. The cylinder heads were small and acted as the limiting factor in the combination.

The subject of linear is an extensive one. Keeping everything moderate is a good step in that direction: moderate timing, launch point, shift point, and fuel enrichment. In our case, we know what our air to fuel ratio is from jet area and air calculations from Fuel Injection Racing Secrets. We know our rich air to fuel ratio limit and our lean air to fuel ratio limit and we keep in the middle. It is difficult to get there without record keeping and some calculations or data measurements. And we found that method to be very repeatable year after year after year. And once we found it, we race in that range and never had to recalculate or find it again.