You’ve got questions. We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we offer up tips for routing your fuel lines.
J.H. Boston, MA
Q: I am getting ready to plumb my fuel system and can use some advice on routing the fuel lines. What’s the best way to route the lines and what type of fuel line should I use? Finally, what type of fuel fittings should I use?
A: Fuel lines should be routed to avoid hot spots and promote maximum fuel flow. Avoid sharp turns or bends in the fuel line routing as they can cause undue restrictions to the flow of fuel. Most factory fuel systems utilize 5/16-inch fuel line, which works well on street applications with stock engines. A -6 AN (3/8″) line size is sufficient for all street performance applications and some racing applications. -8 AN (1/2″) fuel lines are used on everything else, including alcohol applications.
As far as fuel line material, you should avoid using rubber fuel lines (or use them sparingly) for two reasons. First, rubber is more resistant to the flow of fuel than hard line and a pressure loss will result. Second, hard line is safer, especially when using a high pressure performance fuel pump.
Like fuel lines, fittings are also very important in the total fuel line system. They should be the same size as the fuel line, and you’ll want to minimize the use of 90-degree fittings as much as possible. Again, sharp turns and bends within the fuel lines can cause restriction.