Be it air, water, fuel, or oil, they all generally flow the quickest and most efficiently in a straight line. For that reason, racers that demand every last ounce of performance out of their machines have long avoided 90-degree elbows in their fuels systems, to eliminate any possibility of fuel flow disruption or degradement between the pump and the fuel rails or the carburetor. This, of course, can have even more disastrous consequences in a nitrous or boosted application, as a lower-than-intended fuel pressure at the entry point to the engine can result in burned pistons and others broken parts, never mind inconsistencies in the tune-up.
But if push comes to shove and you’ve got to replace a fitting at the track, can fuel really flow just as well through a 90-degree fitting as a 45-degree junction?
Steve Johnson of Induction Solutions has as much experience with nitrous oxide and fuel as anyone in drag racing, and he believes it can — given the fuel system is properly sized and set up right. As he says, “a 90-degree fitting would not be the end of the world.”
To illustrate and quantify this, Johnson cut a hole in a plug and put the fittings to the test. Up first, the 45-degree, as expected, delivered the roughly 500 lb-hr of fuel that he was aiming for. He then strung together not one, not two, but three 90-degree Fragola fittings in an obstacle course of tight radiuses, flipped on the pump, and registered the very same 500 lb-hr as with the lone 45.
Certainly everyone has their own opinion on fittings, but as far as Johnson is concerned, this myth is debunked.