We've talked about the necessity of EGT/Boost gauges, beyond protecting the engine from excessive exhaust temperatures, but also as a way to help manage the powertrain more effectively. I've thought for some time about how to illustrate that fact, especially when it comes to fuel economy. During a drive this weekend, I carefully watched the EGT's and its relationship to vehicle speeds, and am offering a rough estimate for a way to use the EGT gauge as a tool to manage the powertrain for better fuel economy....

While the numbers may be massaged over time, a best guess would put 600 degrees EGT at an optimum (while driving not too fast or too slow) exhaust temperature for fuel economy, and which should produce very close to 20 mpg (or more) if that 600 figure is maintained. In my truck, that means about 60 mph. 65 mph pushes EGT to 650-700 degrees. Running 75 or a touch more pushes EGT above those numbers.

We need your help..... We need more data. If you can log a tank of fuel at a constant EGT at a particular speed, let us know your MPG results. More data means we can plot the EGT and MPG, and arrive at a statistical value that could very well become a "rule" - than the current best guess we have now.

Thanks!

Jim