flyinsquirel

I'm setting up my fuel system and I notice that everyone seems to be running a 3/8" feed line from the corvette regulator/filter to the fuel rails. But in looking at the in tank set up I got from Tanks Inc. the line coming off the intank walbro is 5/16". Maybe I'm missing something but it doesn't seem to make any sense to run a 3/8" feed when upstream the pump is hooked to a 5/16". I'm no expert on fluid dynamics and flow rates so clue me in. Can someone fill me in on why I should run a bigger line than what hooks to the pump? Does the higher pressure behind the regulator allow the smaller line to make full use of the bigger line on the other sides increased volume capacity?

Reason I ask is my car already has a 5/16" hard line to the front of the car that I would like to use if it's not going to cause me problems. I'm running a stock 2000 LS1 out of a WS6, and I have no plans for any power upgrades at this time.

Thanks

Lonnies Performance

iTrader: (16)

The smallest diameter of a given fuel system is not the limiting factor. Every section of line, each fitting etc., represents a restriction, which creates a certian pressure drop relative to the total capacity. If you look in more detail you will see the pump outlet is approx 1/4" with a schrader valve in the opening.

This is simple terms means a smaller line has more pressure drop per foot than a larger one. As long as the pressure drop does not exceed the required pressure at max flow, you are good. I typically use only -8 if I am replacing lines as costs are barely more than smaller sized & always allow for future power increases.

Personally I would run a minimum of 3/8" line & be safe.

If you are converting a carb application, I always suggest new line anyway... any contamination will clog your injectors unless the filter is located in the extreme front of the car.

jeepnut24

Bump because Im facing the same situation and would like some input. My Jeep has a 5/16" for the old FI. Isn't this going to be a problem when I replace from the pump forward with 3/8" ??

jimmyblue

iTrader: (11)

You're not pushing marbles, it's a fluid. Flow is like the
sum of all the segments' (area/length), rolled up. The long
runs matter most and you'd want to "fix" them with area.