7.3 idi fuel supply/return issues

[The_Josh_Bear]

It does affect it, I have found that when setting up the governor for idle fuel rate on the flow bench (with the top cover off) that it flows about 5-10cc less with the cover back on. I knocked out the ball in fitting of the return port and gained some flow. By bumping up my inlet fuel pressure my fuel temperature also went down which increased flow as well. I’m working on a write up for just stock fuel mods to get as much as you can out of a stock pump.

That's sweet, cant wait to read it!
Why would colder fuel flow better? Just due to poor pump tolerances internally?

 

[Thewespaul]

The viscosity change helps fuel flow, but the tolerances will be slightly tighter with a cooler pump. This is why I’m working on a fuel cooler as well